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Compatibility Study between Fenbendazole and Polymeric Excipients Used in Pharmaceutical Dosage Forms Using Thermal and Non-Thermal Analytical Techniques

Compatibility Study between Fenbendazole and Polymeric Excipients Used in Pharmaceutical Dosage... Article Compatibility Study between Fenbendazole and Polymeric Excipients Used in Pharmaceutical Dosage Forms Using Thermal and Non-Thermal Analytical Techniques Gilberto S. N. Bezerra *, Vicente F. Moritz, Tielidy A. de M. de Lima, Declan M. Colbert, Joseph Geever and Luke Geever * PRISM Research Institute, Technological University of the Shannon: Midlands Midwest, University Road, N37HD68 Athlone, Ireland * Correspondence: a00278630@student.ait.ie (G.S.N.B.); lgeever@ait.ie (L.G) Abstract: The body of work described in this research paper evaluates the compatibility between Fenbendazole (Fen), which is a broad-spectrum anthelmintic with promising antitumor activity, and three polymeric excipients commonly applied in pharmaceutical dosage forms. The assessment of binary mixtures was performed by differential scanning calorimetry and thermogravimetric analysis/derivative thermogravimetry to predict physical and/or chemical interactions, followed by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), and high- performance liquid chromatography (HPLC) to confirm or exclude any interactions. Thermal studies suggested the presence of interactions between Fen and P 407, PCL, and PLA. To validate these data, XRD showed that Fen is compatible with PCL and PLA, suggesting some interaction with P 407. FTIR demonstrated that PCL and PLA can establish physical interactions with Fen; moreover, it suggested Citation: Bezerra, G.S.N.; Moritz, that P 407 interacts not only physically but also chemically, which was later proved by HPLC to be V.F.; de Lima, T.A.d.M.; Colbert, D.M.; only new intermolecular interactions. This work supports the further application of P 407, PCL, and Geever, J.; Geever, L. Compatibility PLA for the development of new medicinal and veterinary formulations containing Fen, since they Study between Fenbendazole and do not affect the physical and chemical characteristics of the active ingredient and consequently its Polymeric Excipients Used in Pharmaceutical Dosage Forms Using bioavailability and therapeutic efficacy. Thermal and Non-Thermal Analytical Techniques. Analytica 2022, 3, 448–461. Keywords: compatibility study; fenbendazole; polymeric excipients https://doi.org/10.3390/ analytica3040031 Academic Editors: Marcello Locatelli 1. Introduction and Victoria Samanidou Methyl N-(6-phenylsulfanyl-1H-benzimidazol-2-yl)carbamate or Fenbendazole (Fen) Received: 25 October 2022 is a member of the benzimidazole family [1]. Fen has a broad spectrum of activities includ- Accepted: 7 December 2022 ing antiparasitic [2], fungicidal [3], antiviral [4], and, particularly, antitumor [5], demon- Published: 12 December 2022 strating a promising effect against different types of cancer, such as skin [6], prostate [7], Publisher’s Note: MDPI stays neutral and kidney [8], with potential application in medicinal and veterinary formulations. with regard to jurisdictional claims in Pharmaceutical dosage forms consist of APIs (active pharmaceutical ingredients) and published maps and institutional affil- suitable excipients, which must be pharmacologically inert, physically and chemically iations. compatible, non-toxic, and not affect the drug’s bioavailability [9]. Hence, the first step for the development of a pharmaceutical formulation should be a preformulation study, which predicts possible incompatibilities between the API and excipients, investigating potential physical and chemical interactions that can compromise the stability, safety, and efficacy of Copyright: © 2022 by the authors. the final product [10]. Furthermore, the U.S. Food and Drug Administration has launched Licensee MDPI, Basel, Switzerland. new regulations establishing drug-excipient compatibility studies as vital for the approval This article is an open access article of new formulations [11]. distributed under the terms and Based on the variety of polymers available and under development, the screening and conditions of the Creative Commons selection of polymers compatible with the API can be challenging. Therefore, new, fast Attribution (CC BY) license (https:// and reliable analytical techniques are required to identify suitable polymeric excipients creativecommons.org/licenses/by/ 4.0/). Analytica 2022, 3, 448–461. https://doi.org/10.3390/analytica3040031 https://www.mdpi.com/journal/analytica Analytica 2022, 3 449 for a new formulation as they play roles such as binders, lubricants, suspending, fillers, solubility enhancers, and stabilizing agents, among other functions [12]. The assessment of binary mixtures using thermoanalytical techniques to predict phys- ical and/or chemical interactions between the API and excipients has been extensively reported [10,13–15]. Differential scanning calorimetry (DSC) and thermogravimetric anal- ysis (TGA) have been the most applied techniques for this purpose. Even though the association of data collected from two thermal techniques such as DSC and TGA enables better characterisation of the events related to a sample, this interpretation must be sup- ported by other analytical techniques, such as X-ray diffraction spectroscopy (XRD), Fourier transformed infrared spectroscopy (FTIR), and high-performance liquid chromatography (HPLC). These techniques have been widely applied to confirm or exclude the events suggested by thermal studies [10,13–19]. Moreover, the application of analytical techniques to quickly and efficiently predict incompatibilities between the API and excipients have a direct impact on the pharmaceuti- cal research and development sectors, avoiding trial and error, preventing raw material wastage, reducing the time required for the development of new formulations, and, conse- quently, decreasing costs [20]. Shakar et al. [19] during the development of a solid dosage form found a low dissolution profile to bisoprolol fumarate and suspected there was some chemical interaction between the API and the disintegrating agents. After HPLC and DSC analysis, they identified that bisoprolol is incompatible with sodium starch glycolate and croscarmellose sodium, which could have been predicted if a prior compatibility study was performed. To the best of our knowledge, there are very few studies predicting physical and/or chemical interactions between Fen and polymeric excipients commonly applied in phar- maceutical dosage forms [17,21]. Therefore, this work aims to study the compatibility between Fen and three polymeric excipients widely applied in drug delivery, namely P 407, PCL, and PLA, using thermal (DSC and TGA/DTG), spectroscopic (XRD and FTIR), and chromatographic (HPLC) techniques. This work is expected to guide the development of new medicinal and veterinary formulations, mainly generic ones, for those in which a careful selection of excipients is required. 2. Materials and Methods 2.1. Materials Fen was purchased from Molekula (Darlington, UK), Tri-block copolymer of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (Kolliphor P 407 Geismar—P 407, Mw 12,000 g mol ) was obtained from BASF (Burgbernheim, Germany), Polycaprolactone ® 1 (CAPA 6506—PCL, Mw 50,000 g mol ) was supplied by Perstorp (Warrington, UK), ® 1 and Poly(lactic acid) (Ingeo 2003D—PLA, Mw 180,477 g mol ) was purchased from NatureWorks (Minnetonka, MN, USA). All other chemicals and reagents were of analytical reagent grade. The chemical structures of Fen and the polymeric excipients used in this study are shown in Figure 1. 2.2. Binary Mixtures Binary mixtures between Fen and each polymeric excipient were prepared in a 1:1 (w/w) ratio with the components mixed using a pestle and mortar. This ratio was chosen to maximize the probability of observing potential interactions [22]. Analytica 2022, 3, FOR PEER REVIEW 3 Analytica 2022, 3 450 Figure 1. Chemical structures of (a) Fen, (b) P 407, (c) PCL, and (d) PLA designed using MarvinSketch 15. 4.6. Figure 1. Chemical structures of (a) Fen, (b) P 407, (c) PCL, and (d) PLA designed using 2.3. Thermal Analyses—DSC and TGA/DTG MarvinSketch 15.4.6. DSC curves were obtained using a Pyris 6 DSC (PerkinElmer, Waltham, MA, USA). Fen thermal characterisation was performed in triplicate using between 6 and 8 mg of the 2.2. Binary Mixtures sample in lid-sealed aluminium pans, under a nitrogen atmosphere with a flow of 30 mL Binary mixtures between Fen and each polymeric excipient were prepared in a 1:1 1  1 min and a heating rate of 10 C min from 40 to 300 C. Calorimetric curves of neat (w/w) ratio with the components mixed using a pestle and mortar. This ratio was chosen polymers and binary mixtures were performed using between 6 and 8 mg of the sample in to maximize the probability of observing potential interactions [22]. lid-sealed aluminium pans, under a nitrogen atmosphere with a flow of 30 mL min and a heating rate of 10 C min from 30 to 300 C. 2.3. Thermal Analyses—DSC and TGA/DTG TGA curves were obtained using a Pyris 1 TGA (PerkinElmer, Waltham, MA, USA). DSC curves were obtained using a Pyris 6 DSC (PerkinElmer, Waltham, MA, USA). Fen was analysed in triplicate using 10 mg of the sample in aluminium pans, under a Fen thermal characterisation was performed in 1triplicate using between  6 and 8 mg 1 of the nitrogen atmosphere with a flow of 20 mL min and a heating rate of 10 C min from 40 sample in lid-sealed aluminium pans, under a nitrogen atmosphere with a flow of 30 mL to 700 C. Thermogravimetric curves of neat polymers and binary mixtures were performed −1 −1 min and a heating rate of 10 °C min from 40 to 300 °C. Calorimetric curves of neat using 10 mg of the sample in aluminium pans, under a nitrogen atmosphere with a flow of 1  1 polymers and binary mixtures were performed using between 6 and 8 mg of the sample 20 mL min and a heating rate of 10 C min from 40 to 700 C. −1 in lid-sealed aluminium pans, under a nitrogen atmosphere with a flow of 30 mL min DSC and TGA/DTG measurements were performed using Pyris—Instrument Manag- −1 and a heating rate of 10 °C min from 30 to 300 °C. ing Software (PerkinElmer, Waltham, MA, USA). TGA curves were obtained using a Pyris 1 TGA (PerkinElmer, Waltham, MA, USA). 2.4. X-ray Diffraction Spectroscopy Fen was analysed in triplicate using 10 mg of the sample in aluminium pans, under a −1 −1 nitrogen atmosphere with a flow of 20 mL min and a heating rate of 10 °C min from 40 Diffractograms were obtained using a Siemens D500 X-ray powder diffractometer to 700 °C. Thermogravimetric curves of neat polymers and binary mixtures were per- (Karlsruhe, Germany) with Cu Ka radiation (l = 0.15418 nm). The 2 (theta) range applied formed using 10 mg of the sample in aluminium pans, under a nitrogen atmosphere with for the test was 10 to 80 . −1 −1 a flow of 20 mL min and a heating rate of 10 °C min from 40 to 700 °C. 2.5. Fourier Transform Infrared Spectroscopy DSC and TGA/DTG measurements were performed using Pyris - Instrument Man- aging Attenuated Software (Perk total inElm reflectance er, Wal Fourier tham, M transform A, USA). infrared spectroscopy (ATR-FTIR) of the samples was carried out on a Perkin Elmer Spectrum (Waltham, MA, USA), with 4 scans 2.4. per X sample, -ray Dif in fra the ction spectral Spectro range scopy from 650 to 4000 cm , and a fixed universal compression force of 85 N. Diffractograms were obtained using a Siemens D500 X-ray powder diffractometer (Karlsruhe, Germany) with Cu Kα radiation (λ = 0.15418 nm). The 2θ (theta) range applied 2.6. High-Performance Liquid Chromatography for the test was 10° to 80°. HPLC analysis was carried out using a system consisting of a Waters Alliance e2695 separations module combined with a Waters 2487 dual  absorbance detector (Waters 2.5. Fourier Transform Infrared Spectroscopy Chromatography Ireland Ltd., Dublin, Ireland). The chromatographic analyses of neat Fen Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) of and binary mixtures were performed using the protocol published by Ali et al. [23] with the samples was carried out on a Perkin Elmer Spectrum (Waltham, MA, USA), with 4 minor modifications. A Thermo Scientific BDS Hypersil C8 column (250 mm  4.60 mm, −1 scans per sample, in the spectral range from 650 to 4000 cm , and a fixed universal com- 5 m) (Fisher Scientific Ireland Ltd., Dublin, Ireland) maintained at ambient temperature pression force of 85 N. was used as the stationary phase. The mobile phase consisted of methanol and 0.025 M monopotassium phosphate (70:30 v/v) adjusted to pH 3.20 using ortho-phosphoric acid, Analytica 2022, 3, FOR PEER REVIEW 4 2.6. High-Performance Liquid Chromatography HPLC analysis was carried out using a system consisting of a Waters Alliance e2695 separations module combined with a Waters 2487 dual λ absorbance detector (Waters Chromatography Ireland Ltd, Dublin, Ireland). The chromatographic analyses of neat Fen and binary mixtures were performed using the protocol published by Ali et al. [23] with minor modifications. A Thermo Scientific BDS Hypersil C8 column (250 mm × 4.60 mm, 5 µ m) (Fisher Scientific Ireland Ltd, Dublin, Ireland) maintained at ambient temperature Analytica 2022, 3 451 was used as the stationary phase. The mobile phase consisted of methanol and 0.025 M monopotassium phosphate (70:30 v/v) adjusted to pH 3.20 using ortho-phosphoric acid, −1 filtered, and degassed. A flow rate of 1 mL min was maintained during the procedure, filtered, and degassed. A flow rate of 1 mL min was maintained during the procedure, the detector was set at 288 nm, and the sample injection volume was 10 µ L. Further anal- the detector was set at 288 nm, and the sample injection volume was 10 L. Further analyses yses were performed using Empower software. were performed using Empower software. 3. Results 3. Results 3.1. Thermal Characterisation of Fenbendazole 3.1. Thermal Characterisation of Fenbendazole Figure 2 shows the DSC curves of Fen characterised by a sharp endothermic peak at Figure 2 shows the DSC curves of Fen characterised by a sharp endothermic peak at −1 244 °C  (ΔH = 252 J g ) 1corresponding to the melting point, followed by decomposition at 244 C (DH = 252 J g ) corresponding to the melting point, followed by decomposition −1 271 °C (ΔH = 27 J g ). Though the literature reports the same calorimetric pattern of melt- at 271 C (DH = 27 J g ). Though the literature reports the same calorimetric pattern of ing followed by decomposition [24], there is a lack of consensus about the Fen melting melting followed by decomposition [24], there is a lack of consensus about the Fen melting temperature (Tm) because it relies on the heating rate applied, nitrogen flow rate, and other temperature (T ) because it relies on the heating rate applied, nitrogen flow rate, and other parameters. For instance, Attia et al. [25] identified the melting peak of Fen at 230 °C, parameters. For instance, Attia et al. [25] identified the melting peak of Fen at 230 C, Rodrigues et al. [26] at 214 °C, and Melian et al. [21] at 210 °C. Rodrigues et al. [26] at 214 C, and Melian et al. [21] at 210 C. −1 Figure 2. DSC curve of Fen at a heating rate of 10 °C min .1 Figure 2. DSC curve of Fen at a heating rate of 10 C min . In Figure 3, the TGA/DTG curves demonstrate that Fen is stable below 164 °C fol- In Figure 3, the TGA/DTG curves demonstrate that Fen is stable below 164 C followed lowed by four main stages of degradation. The first stage of mass loss is from 164 to 269 by four main stages of degradation. The first stage of mass loss is from 164 to 269 C °C (∆m = 13%) with Tpeak DTG = 241 °C, the second is from 270 to 357 °C (∆m = 8%) with (Dm = 13%) with T DTG = 241 C, the second is from 270 to 357 C (Dm = 8%) with peak Tpeak DTG = 334 °C, the third is from 358 to 506 °C (∆m = 34%) with Tpeak DTG = 428 °C, and T DTG = 334 C, the third is from 358 to 506 C (Dm = 34%) with T DTG = 428 C, peak peak th and e las the t is last frois m fr 507 omto 507 700 to °C 700 (∆m C= (34% Dm ) =w 34%) ith Twith peak DTG T = 67 DTG 2 °C = . Th 672 e di C. ffe The rencdif e in fer ma ence ss peak loss in mass (∆m loss = 11%) (Dm corre = 11%) spon corr ds to esponds the carbon to the aceou carbonaceous s residue. Si rm esidue. ilar resu Similar lts were results described were in described the literain ture the by literatur Attia et eal. by [25] Attia . Thet ey al. describe [25]. d They that described Fen is stable that up Fen to 179 is stable °C followed up to by 179fou Cr followed stages of by mass four loss stages . The fi of rst mass stage loss. is bet The ween first 179 stage and is 24 between 5 °C (∆m 179 = 10% and ) char 245 ac- C (Dm = 10%) characterised by the loss of the sulphur atom, the second is between 245 and terised by the loss of the sulphur atom, the second is between 245 and 345 °C (∆m = 10%) 345 C (Dm = 10%) represented by the loss of CH O, the third is between 345 and 461 C represented by the loss of CH3O, the third is between 345 and 461 °C (∆m = 35%) associated (Dm = 35%) associated with the loss of C H and CO molecules, and the last one is between with the loss of C6H5 and CO molecule6 s, and 5 the last one is between 461 and 746 (∆m = 461 and 746 (Dm = 43%) represented by the loss of the C H N molecule. 43%) represented by the loss of the C7H5N3 molecule. 7 5 3 After the API thermal characterisation, it is reasonable to evaluate its physical and chemical interactions with the polymeric excipients since the incompatibility between them can affect the pharmaceutical dosage form properties, and, consequently, the therapeutic efficacy [14]. Therefore, it is required to analyse the DSC and TGA/DTG curves of each neat ingredient followed by their comparison with the curves of the binary mixtures to identify possible alterations of the API thermal behaviour. Analytica 2022, 3 452 Analytica 2022, 3, FOR PEER REVIEW 5 −1 Figure 3. TGA/DTG curves of Fen at a heating rate of 10 °C min . Figure 3. TGA/DTG curves of Fen at a heating rate of 10 C min . 3.2. Thermal After thAnalysis e API thof ermal the Physical characteri Mixtur sation es by , it DSC is reason and TGA/DTG able to evaluate its physical and chemical interactions with the polymeric excipients since the incompatibility between Figures 4–6 show the calorimetric and thermogravimetric curves of neat Fen, neat poly- them can affect the pharmaceutical dosage form properties, and, consequently, the thera- meric excipients, and physical mixtures with all the thermal events numerically described peutic efficacy [14]. Therefore, it is required to analyse the DSC and TGA/DTG curves of in Table 1. each neat ingredient followed by their comparison with the curves of the binary mixtures Table 1. Thermoanalytical data of neat excipients and physical mixtures between Fen + polymeric to identify possible alterations of the API thermal behaviour. excipients 1:1 (w/w) at a heating rate of 10 C min . 3.2. Thermal Analysis of the Physical Mixtures by DSC and TGA/DTG DSC TGA DTG Figures 4–6 show the calorimetric and thermogravimetric curves of neat Fen, neat Excipients Transition T [ C] T [ C] DT [ C] Dm [%] T [ C] DH [J g ] onset m peak polymeric excipients, and physical mixtures with all the thermal events numerically de- 1st Endo 51 57 185 scribed in Table 1. P 407 146–398 96 288 1st Endo 55 63 112 233–470 92 409 PCL Table 1. Thermoanalytical data of neat excipients and physical mixtures between Fen + polymeric 471–547 6 514 −1 excipients 1:1 (w/w) at a heating rate of 10 °C min . 1st Endo 145 152 48 PLA 286–411 98 378 DSC TGA DTG −1 a Excipients Transition Tonset [° C] Tm [° C] ΔH [J g ] ∆T [° C] ∆m [%] Tpeak [° C] Physical 1  a Transition T [ C] T [ C] DT [ C] Dm [%] T [ C] onset m DH [J g ] peak 1st Endo 51 57 185 mixtures P 407 146–398 96 288 1st Endo 52 58 88 1st Endo 55 63 112 2nd Endo 219 236 46 142–301 11 233 PCL 233–470 92 409 Fen + P 407 3rd Endo 268 283 17 302–339 5 319 471–547 6 514 340–480 52 378 1st Endo 145 152 48 PLA 481–700 28 615 286–411 98 378 1st Endo 56 62 54 −1 a Physical mixtures Transition Tonset [° C] Tm [° C] ΔH [J g ] ∆T [° C] ∆m [%] Tpeak [° C] 2nd Endo 217 235 71 140–274 6 230 1st Endo 52 58 88 Fen + PCL 3rd Endo 268 283 12 275–433 63 398 2nd Endo 219 236 46 142–301 11 233 434–497 6 462 Fen + P 407 3rd Endo 268 283 17 302–339 5 319 498–700 22 591 340–480 52 378 1st Endo 143 148 3 2nd Endo 225 232 100 173–234 481–700 2 28 216 615 1st Endo246 56 250 62 2 54 235–259 2 239 Fen + PLA 3rd Endo 2nd Endo 217 235 71 140–274 6 230 260–449 78 320 3rd Endo 268 283 12 450–700 275–433 15 63 604 398 Fen + PCL 434–497 6 462 DT ranges between T and T onset endset. 498–700 22 591 1st Endo 143 148 3 2nd Endo 225 232 100 173–234 2 216 Fen + PLA 3rd Endo 246 250 2 235–259 2 239 260–449 78 320 450–700 15 604 ∆T ranges between Tonset and Tendset. Analytica 2022, 3, FOR PEER REVIEW 6 Analytica 2022, 3 453 Figure 4. Thermal behaviour of P 407—DSC (a), TGA (b), and DTG (c) at a heating rate of Figure 4. Thermal behaviour of P 407—DSC (a), TGA (b), and DTG (c) at a heating rate of 10 °C 1 −1 10 C min . Fen min (red), . Fen neat (redpolymer ), neat polym (black), er (blac and k), physical and physic mixtur al mixtur e (blue). e (blue). In general, the calorimetric curve of Fen displays a well-defined endothermic peak characteristic of fusion at 244 C (DH = 252 J g ). Hence, any displacement or disap- pearance of this peak and/or a degree of variation in enthalpy values can indicate either physical or chemical interactions [13,17]. P 407 (Figure 4a) shows a single endothermic peak characteristic of the polymer melt- ing at 57 C (DH = 185 J g ), which matches with another study [27]. The calorimetric curve of the physical mixture shows three endothermic peaks at 58 C (DH = 88 J g ), 1  1 236 C (DH = 46 J g ), and 283 C (DH = 17 J g ), with an expressive reduction of Fen melting peak anticipated by 8 C. The TGA curve (Figure 4b) demonstrates a decrease of Fen thermal stability from 164 to 142 C, representing 22 C. Kolašinac et al. [27] studied physical mixtures between poloxamer 407 and desloratadine; they reported that the poly- mer melting point remained unchanged but the desloratadine melting peak shifted to a lower temperature, suggesting an interaction between them. Analytica 2022, 3 Analytica 2022, 3, FOR PEER REVIEW 454 7 Figure 5. Thermal behaviour of PCL—DSC (a), TGA (b), and DTG (c) at a heating rate of 10 C min . −1 Figure 5. Thermal behaviour of PCL—DSC (a), TGA (b), and DTG (c) at a heating rate of 10 °C min . Fen (red), neat polymer (black), and physical mixture (blue). Fen (red), neat polymer (black), and physical mixture (blue). PCL (Figure 5a) displays a single endothermic peak characteristic of the polymer melting at 63 C (DH = 112 J g ), which agrees with the literature [28]. The DSC curve of the binary mixture displays three endothermic peaks at 62 C (DH = 54 J g ), 235 C 1  1 (DH = 71 J g ), and 283 C (DH = 12 J g ), with reduction of Fen melting peak and anticipation of 9 C. The thermogravimetric curve (Figure 5b) shows a decrease in Fen thermal stability of 24 C from 164 to 140 C. In another study conducted by Yoganathan and Mammucar [29], they also reported a shift of the ibuprofen melting point when loaded in PCL, but their TGA analysis showed no alteration of the drug thermal degradation. Analytica 2022, 3, FOR PEER REVIEW 8 Analytica 2022, 3 455 Figure 6. Thermal behaviour of PLA—DSC (a), TGA (b), and DTG (c) at a heating rate of −1 Figure 6. Thermal behaviour of PLA—DSC (a), TGA (b), and DTG (c) at a heating rate of 10 °C min . 10 C min . Fen Fen (red), (red), neat neat polymer polymer ( (black), black), and and ph physical ysical mmixtur ixture (blue). e (blue). PLA (Figure 6a) In demonstrates general, the calo arimetric glass transition curve of Fen (T dis ) at pl63 ays C a w followed ell-defined byendot a melting hermic peak 1 −1 characteristic of fusion at 244 °C (ΔH = 252 J g ). Hence, any displacement or disappear- peak at 152 C (DH = 48 J g ) as described in other studies [30–32]. The calorimetric ance of this peak and/or a degree of variation in enthalpy values can indicate either phys- curve of the physical mixture presents three endothermic peaks at 148 C (DH = 3 J g ), ical or chem 1 ical interactions [13,17]. 1 232 C (DH = 100 J g ), and 250 C (DH = 2 J g ) followed by not only a reduction of Fen P 407 (Figure 4a) shows a single endothermic peak characteristic of the polymer melt- melting peak but also an anticipation of 12 C. The thermogravimetric curve (Figure 6b) −1 ing at 57 °C (ΔH = 185 J g ), which matches with another study [27]. The calorimetric curve displays an increase in Fen thermal stability of 9 C from 164 to 173 C. Li et al. [31], who −1 of the physical mixture shows three endothermic peaks at 58 °C (ΔH = 88 J g ), 236 °C (ΔH studied PLA and dexamethasone, also reported a decrease in the API melting point, but it −1 −1 = 46 J g ), and 283 °C (ΔH = 17 J g ), with an expressive reduction of Fen melting peak did not affect the drug properties. anticipated by 8 °C. The TGA curve (Figure 4b) demonstrates a decrease of Fen thermal After analysing the calorimetric curves, we can see that all physical mixtures display stability from 164 to 142 °C, representing 22 °C. Kolašinac et al. [27] studied physical three endothermic peaks; the first one is attributed to the respective polymer melting transition, the second to Fen melting point, and the third is characteristic of decomposition. All polymeric excipients under study had some impact on Fen thermal behaviour, which can be mainly described as follows: (i) shifting the melting point, (ii) decreasing the melting peak area and height becoming broadened and lowered, and (iii) reducing the enthalpy of Analytica 2022, 3 456 fusion. This is an indication of interaction between Fen and each polymeric excipient, but it must be studied by other analytical techniques, such as XRD, FTIR, and HPLC, to confirm or exclude it. 3.3. Physical and Chemical Analysis of the Mixtures by XRD, FTIR, and HPLC To further investigate any possible interactions between Fen and each polymeric excipient, XRD, FTIR and HPLC were employed in this study through qualitative analyses to obtain more information to support the DSC and TGA/DTG results. The results obtained from Fen diffractogram (Figure 7) reveal its crystalline character- istics with seven well-evidenced peaks appearing at 2 = 10.40, 12.59, 17.57, 25.31, 25.81, 26.50, and 30.98 with similar results found in the literature [21,33]. After analysing each neat polymeric excipient, their diffractograms revealed the following: P 407 displayed two main signals at 2 = 18.73 and 23.81 (Figure 7a) [21]; PCL exhibited two peaks at 2 = 20.70 and 23.19 (Figure 7b) [34]; and PLA showed a broad diffraction peak associated with its Analytica 2022, 3, FOR PEER REVIEW 10 amorphous regions at 2 = 10–25 , which likely covered up the crystalline domains’ peaks (Figure 7c), as the DSC analysis proved the existence of crystallinity due to the appearance of the polymer melting peak at 152 C [35]. Figure 7. XRD shows the main diffraction peaks characteristic of neat Fen followed by physical Figure 7. XRD shows the main diffraction peaks characteristic of neat Fen followed by physical mix- mixtures between Fen and (a) P 407, (b) PCL, and (c) PLA. FTIR shows the main signals characteristic tures between Fen and (a) P 407, (b) PCL, and (c) PLA. FTIR shows the main signals characteristic of neat Fen followed by physical mixtures between fen and (d) P 407, (e) PCL, and (f) PLA. Fen (red), of neat Fen followed by physical mixtures between fen and (d) P 407, (e) PCL, and (f) PLA. Fen neat polymers (black), and physical mixtures (blue). (red), neat polymers (black), and physical mixtures (blue). X-ray diffraction patterns obtained from the physical mixtures are virtually the simple X-ray diffraction patterns obtained from the physical mixtures are virtually the sim- superposition of the patterns corresponding to the crystalline phase of each component of ple superposition of the patterns corresponding to the crystalline phase of each compo- the mixture. Despite not seeing any additional crystalline peak, P 407 led to a reduction of nent of the mixture. Despite not seeing any additional crystalline peak, P 407 led to a re- some of the main diffraction peaks of the API, such as 2 = 17.57, 25.31, 25.81 and 26.50 , duction of some of the main diffraction peaks of the API, such as 2θ = 17.57, 25.31, 25.81 which indicates some type of interaction between them. Therefore, further investigation and 26.50°, which indicates some type of interaction between them. Therefore, further in- with FTIR is required to exclude any incompatibility since there is the possibility of a vestigation with FTIR is required to exclude any incompatibility since there is the possi- chemical interaction happening between the amorphous regions of the components, which bility of a chemical interaction happening between the amorphous regions of the compo- would not be noticeable by XRD. nents, which would not be noticeable by XRD. The FTIR spectrum of Fen was confirmed by comparison with SpectraBase—Wiley The FTIR spectrum of Fen was confirmed by comparison with SpectraBase—Wiley (43210-67-9), which allowed the identification of its absorption bands. Figure 7 shows the (43210-67-9), which allowed the identification of its absorption bands. Figure 7 shows the main infrared signals characteristic of Fen at 3336 cm assigned to the (N-H) stretching −1 main infrared signals characteristic of Fen at 3336 cm assigned to the (N-H) stretching mode from the carbamate group, 1630 cm attributed to the (N-H) bending and the −1 mode from the carbamate group, 1630 cm attributed to the (N-H) bending and the (C-N) 1 1 (C-N) stretching modes, 742 cm assigned to the (phenyl), and 685 cm attributed −1 −1 stretching modes, 742 cm assigned to the (phenyl), and 685 cm attributed to the (ben- zenethiol) [21,36–38]. Other less relevant infrared signals are described in the literature −1 −1 such as 3050–2954 cm attributed to the (C-H) tension mode, 2650 cm assigned to the (N- −1 H) stretching mode of the benzimidazole ring, 1708 cm attributed to the (C=O) stretching −1 −1 vibrations of the carbamate carbonyl, 1442 cm assigned to the (C-N), 1222 cm attributed −1 to the (C-O), and 1099 cm attributed to the phenyl-(o) [36,37]. After analysing the infrared profile of Fen, we studied the spectrum of each poly- meric excipient to compare them to the spectra of their physical mixtures. The P 407 spec- trum (Figure 7d) demonstrates three main infrared signals identified by (C-H) stretching −1 −1 aliphatic at 2882 cm , (in-plane O-H) bending at 1343 cm , and (C-O) stretching at 1100 −1 cm [39]. The PCL spectrum (Figure 7e) can be characterised by (CH2) vibrations at 2946, −1 −1 2870, and 2821 cm , (C=O) vibrations with a sharp intense peak at 1728 cm , (CH2) bend- −1 −1 ing vibrations at 1465, 1407, and 1362 cm , (COO) vibrations at 1238 and 1181 cm , as well −1 as (C-O) vibrations at 1099 and 1047 cm [40]. The PLA spectrum (Figure 7f) can be iden- −1 −1 tified by stretching frequencies of (C=O) at 1746 cm , (CH3) asymmetric at 2995 cm , (CH3) −1 −1 symmetric at 2946 cm , (C-O) at 1080 cm , and bending frequencies for (CH3) asymmetric −1 −1 at 1452 cm and (CH3) symmetric at 1361 cm [41]. Analytica 2022, 3 457 to the (benzenethiol) [21,36–38]. Other less relevant infrared signals are described in 1 1 the literature such as 3050–2954 cm attributed to the (C-H) tension mode, 2650 cm assigned to the (N-H) stretching mode of the benzimidazole ring, 1708 cm attributed to the (C=O) stretching vibrations of the carbamate carbonyl, 1442 cm assigned to the (C-N), 1 1 1222 cm attributed to the (C-O), and 1099 cm attributed to the phenyl-(o) [36,37]. After analysing the infrared profile of Fen, we studied the spectrum of each polymeric excipient to compare them to the spectra of their physical mixtures. The P 407 spectrum (Figure 7d) demonstrates three main infrared signals identified by (C-H) stretching aliphatic 1 1 1 at 2882 cm , (in-plane O-H) bending at 1343 cm , and (C-O) stretching at 1100 cm [39]. The PCL spectrum (Figure 7e) can be characterised by (CH ) vibrations at 2946, 2870, 1 1 and 2821 cm , (C=O) vibrations with a sharp intense peak at 1728 cm , (CH ) bending Analytica 2022, 3, FOR PEER REVIEW 211 1 1 vibrations at 1465, 1407, and 1362 cm , (COO) vibrations at 1238 and 1181 cm , as well as (C-O) vibrations at 1099 and 1047 cm [40]. The PLA spectrum (Figure 7f) can be 1 1 identified by stretching frequencies of (C=O) at 1746 cm , (CH ) asymmetric at 2995 cm , All the exclusive signals responsible for characterising the API were present without 1 1 (CH ) symmetric at 2946 cm , (C-O) at 1080 cm , and bending frequencies for (CH ) 3 3 the appearance of new ones for the binary mixtures of Fen with PCL and PLA. In general, 1 1 asymmetric at 1452 cm and (CH ) symmetric at 1361 cm [41] any decrease of the components’ main peaks can be a consequence of dilution, mainly All the exclusive signals responsible for characterising the API were present without when working with a drug and polymer ratio of 1:1; furthermore, subtle differences be- the appearance of new ones for the binary mixtures of Fen with PCL and PLA. In general, tween spectra can indicate the presence of intermolecular interactions between Fen and any decrease of the components’ main peaks can be a consequence of dilution, mainly when each polymeric excipient, which is a characteristic of physical interactions [27]. working with a drug and polymer ratio of 1:1; furthermore, subtle differences between By evaluating the whole spectrum of the physical mixture between Fen and P 407 spectra can indicate the presence of intermolecular interactions between Fen and each −1 (Figure 8), we identified the disappearance of a signal at 1125 cm , the appearance of a polymeric excipient, which is a characteristic of physical interactions [27]. −1 −1 new one at 996 cm , followed by two small “shoulders” at 730 and 703 cm . These two By evaluating the whole spectrum of the physical mixture between Fen and P 407 small “shoulders” were present in the spectra of all physical mixtures, but th 1 e literature (Figure 8), we identified the disappearance of a signal at 1125 cm , the appearance of −1 −1 1 1 describes these signals at 730 cm as the in-plane bending mode (C=O) [42] and 703 cm a new one at 996 cm , followed by two small “shoulders” at 730 and 703 cm . These as the carbon out-of-plane bending vibration mode of benzene [43], which clearly are two small “shoulders” were present in the spectra of all physical mixtures, but the liter- physical interactions. Nevertheless, P 407 was the only polymer missing a signal, more ature describes these signals at 730 cm as the in-plane bending mode (C=O) [42] and −1 specifically the one at 1125 cm , which the literature suggests to be interpreted as asym- 703 cm as the carbon out-of-plane bending vibration mode of benzene [43], which clearly metric (C-O-C) stretching vibrations or (C-N) stretching mode representing a physical in- are physical interactions. Nevertheless, P 407 was the only polymer missing a signal, 1 −1 teraction, followed by the presence of a new signal at 996 cm , which is suggestive of a more specifically the one at 1125 cm , which the literature suggests to be interpreted as chemical interaction [42]. asymmetric (C-O-C) stretching vibrations or (C-N) stretching mode representing a physical interaction, followed by the presence of a new signal at 996 cm , which is suggestive of a chemical interaction [42]. Figure 8. Spectral comparison among Fen (red), neat P 407 (black), and physical mixture be- Figure 8. Spectral comparison among Fen (red), neat P 407 (black), and physical mixture between tween Fen and P 407 (blue) to pinpoint the disappearance and appearance of new peaks in the Fen and P 407 (blue) to pinpoint the disappearance and appearance of new peaks in the mixture mixture spectrum. spectrum. Melian et al. [21] evaluated the mixture between Fen and P 407, analysing their most relevant signals and reporting no visible alteration suggestive of a chemical interaction. Contrastingly, Kolašinac et al. [27] described that the spectra of the physical mixture be- tween desloratadine and P 407 are largely similar to the spectra of each component with subtle differences, indicating the existence of intermolecular interactions between them probably due to the formation of hydrogen bonds characterising a physical interaction. In another study, Pezzoli el at. [44] attributed the appearance of a new band in the spectra of their formulations to the occurrence of new intermolecular interactions. Thus, this new band in the spectra of our physical mixture between Fen and P 407 can very likely be justified by the establishment of new intermolecular interactions between drug–polymer. In a preformulation study conducted by Siahi et al. [45], HPLC proved to be an effi- cient qualitative method to confirm the incompatibility between Methyldopa and some pharmaceutical excipients through the presence of a new peak in the chromatograms of Analytica 2022, 3 458 Melian et al. [21] evaluated the mixture between Fen and P 407, analysing their most relevant signals and reporting no visible alteration suggestive of a chemical interaction. Contrastingly, Kolašinac et al. [27] described that the spectra of the physical mixture between desloratadine and P 407 are largely similar to the spectra of each component with subtle differences, indicating the existence of intermolecular interactions between them probably due to the formation of hydrogen bonds characterising a physical interaction. In another study, Pezzoli el at. [44] attributed the appearance of a new band in the spectra of their formulations to the occurrence of new intermolecular interactions. Thus, this new band in the spectra of our physical mixture between Fen and P 407 can very likely be Analytica 2022, 3, FOR PEER REVIEW justified by the establishment of new intermolecular interactions between drug–polymer 12. In a preformulation study conducted by Siahi et al. [45], HPLC proved to be an efficient qualitative method to confirm the incompatibility between Methyldopa and some pharmaceutical excipients through the presence of a new peak in the chromatograms of the binary mixtures. Figure 9 shows the HPLC chromatogram of neat Fen (a) followed by the binary mixtures. Figure 9 shows the HPLC chromatogram of neat Fen (a) followed binary mixtures of Fen and P 407 (b), PCL (c), and PLA (d). HPLC endorses the thermal by binary mixtures of Fen and P 407 (b), PCL (c), and PLA (d). HPLC endorses the and spectroscopic assays indicating the compatibility of the API with PCL, PLA, as well thermal and spectroscopic assays indicating the compatibility of the API with PCL, PLA, as as P 407 without the appearance of new peaks that could support the possibility of chem- well as P 407 without the appearance of new peaks that could support the possibility of ical interactions. chemical interactions. Figure 9. HPLC chromatogram of (a) neat Fen—retention time: 6.81, followed by physical mixtures Figure 9. HPLC chromatogram of (a) neat Fen—retention time: 6.81, followed by physical mixtures between Fen and (b) P 407—6.84 min, (c) PCL—6.84 min, and (d) PLA—6.80 min. between Fen and (b) P 407—6.84 min, (c) PCL—6.84 min, and (d) PLA—6.80 min. Therefore, it can be concluded that the thermal, spectroscopic, and chromatographic Therefore, it can be concluded that the thermal, spectroscopic, and chromatographic assays reported here attest to the physical and chemical compatibility of Fen with P 407, assays reported here attest to the physical and chemical compatibility of Fen with P 407, PCL, and PLA. PCL, and PLA. 4. 4. Co Conclusions nclusions Thermoanalytical techniques such as DSC and TGA/DTG with the support of XRD, Thermoanalytical techniques such as DSC and TGA/DTG with the support of XRD, FTIR, and HPLC have proved herein to be fast and efficient methods for predicting physical FTIR, and HPLC have proved herein to be fast and efficient methods for predicting phys- and/or chemical interactions between Fen and polymeric excipients. ical and/or chemical interactions between Fen and polymeric excipients. Thermal studies suggested the possibility of interactions between Fen and the poly- Thermal studies suggested the possibility of interactions between Fen and the poly- meric excipients due to their capacity of shifting the Fen melting point, decreasing the meric excipients due to their capacity of shifting the Fen melting point, decreasing the melting peak area and height, and reducing the enthalpy of fusion, which can be attributed melting peak area and height, and reducing the enthalpy of fusion, which can be at- to the capacity of the polymers to dissolve part of the Fen crystalline structure during tributed to the capacity of the polymers to dissolve part of the Fen crystalline structure DSC measurements or even due to the heterogeneity in the small samples [13]. To validate during DSC measurements or even due to the heterogeneity in the small samples [13]. To these data, XRD analysis showed that Fen is compatible with PCL and PLA since its main validate these data, XRD analysis showed that Fen is compatible with PCL and PLA since diffraction peaks remained unchanged in the physical mixture, but it suggested some inter- its main diffraction peaks remained unchanged in the physical mixture, but it suggested action with P 407. FTIR proved that PCL and PLA do not have any incompatibility that can some interaction with P 407. FTIR proved that PCL and PLA do not have any incompati- compromise Fen properties. On the other hand, P 407 demonstrated a physical interaction bility that can compromise Fen properties. On the other hand, P 407 demonstrated a phys- ical interaction with Fen possibly by hydrogen bonds and/or hydrophobic interactions; furthermore, we suspected a chemical interaction between them due to the appearance of a new signal, which was later proved by HPLC to be only new intermolecular interactions. In general, a physical interaction can result in polymorphism formation, change the polymorphic form, and lead to the API solubilization with the excipient creating intermo- lecular interactions between their functional groups; nevertheless, it is not considered an incompatibility if the excipient does not change the physical-chemical properties of the API [10]. Thus, these results support the further application of P 407, PCL, and PLA in the development of medicinal and veterinary formulations containing Fen since they do not affect the physical and chemical characteristics of the active ingredient, and consequently its bioavailability and therapeutic efficacy. Moreover, this preformulation study using Analytica 2022, 3 459 with Fen possibly by hydrogen bonds and/or hydrophobic interactions; furthermore, we suspected a chemical interaction between them due to the appearance of a new signal, which was later proved by HPLC to be only new intermolecular interactions. In general, a physical interaction can result in polymorphism formation, change the polymorphic form, and lead to the API solubilization with the excipient creating inter- molecular interactions between their functional groups; nevertheless, it is not considered an incompatibility if the excipient does not change the physical-chemical properties of the API [10]. Thus, these results support the further application of P 407, PCL, and PLA in the development of medicinal and veterinary formulations containing Fen since they do not affect the physical and chemical characteristics of the active ingredient, and consequently its bioavailability and therapeutic efficacy. Moreover, this preformulation study using thermal and non-thermal analytical techniques can be a starting tool for the screening of other suitable polymeric excipients for the development of new pharmaceutical formulations to carry Fen, particularly generic ones, for those in which a careful selection of excipients is required. Author Contributions: Conceptualization, G.S.N.B.; methodology, G.S.N.B.; formal analysis, G.S.N.B. and V.F.M.; investigation, G.S.N.B.; resources, J.G. and L.G.; data curation, G.S.N.B. and V.F.M.; writing—original draft preparation, G.S.N.B.; writing—review and editing, G.S.N.B., V.F.M. and T.A.d.M.d.L.; visualization, G.S.N.B., V.F.M. and T.A.d.M.d.L.; supervision, D.M.C., J.G. and L.G.; project administration, G.S.N.B., D.M.C., J.G. and L.G.; funding acquisition, G.S.N.B., D.M.C., J.G. and L.G. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by the Irish Research Council (IRC), grant number GOIPG/2022/ 1734 and the President Seed Fund from TUS: Midlands and Midwest, grant number PA01007. Acknowledgments: The authors would like to express their gratitude to Daniel Pádraig Fitzpatrick for his support with the FTIR, Lynn Louis for her assistance with the HPLC as well as the technical support of the staff from the Centre for Industrial Services Design (CISD) and Applied Polymer Technologies (APT). Conflicts of Interest: The authors declare no conflict of interest. References 1. National Center for Biotechnology Information. PubChem Compound Summary for CID 3334, Fenbendazole. 2021. Available online: https://pubchem.ncbi.nlm.nih.gov/compound/Fenbendazole (accessed on 1 August 2022). 2. Goossens, E.; Dorny, P.; Vercammen, F.; Vercruysse, J. Field evaluation of the efficacy of fenbendazole in captive wild ruminants. Vet. Record 2005, 157, 582–586. [CrossRef] [PubMed] 3. de Oliveira, H.C.; Joffe, L.S.; Simon, K.S.; Castelli, R.F.; Reis, F.C.G.; Bryan, A.M.; Borges, B.S.; Medeiros, L.C.S.; Bocca, A.L.; Del Poeta, M.; et al. Fenbendazole controls in vitro growth, virulence potential, and animal infection in the Cryptococcus model. Antimicrob. Agents Chemother. 2020, 64, 1–14. [CrossRef] [PubMed] 4. Chang, L.; Zhu, L. Dewormer drug fenbendazole has antiviral effects on BoHV-1 productive infection in cell cultures. J. Vet. Sci. 2020, 21, 1–10. [CrossRef] [PubMed] 5. Duan, Q.; Liu, Y.; Rockwell, S. Fenbendazole as a potential anticancer drug. Anticancer Res. 2013, 33, 355–362. 6. Movahedi, F.; Gu, W.; Soares, C.P.; Xu, Z.P. Encapsulating Anti-Parasite Benzimidazole Drugs into Lipid-Coated Calcium Phosphate Nanoparticles to Efficiently Induce Skin Cancer Cell Apoptosis. Front. Nanotechnol. 2021, 3, 1–13. [CrossRef] 7. Aycock-Williams, A.; Pham, L.; Liang, M.; Adisetiyo, H.A.; Geary, L.A.; Cohen, M.B.; Casebolt, D.B.; Roy-Burman, P. Effects of fenbendazole and vitamin E succinate on the growth and survival of prostate cancer cells. J. Cancer Res. Exp. Oncol. 2011, 3, 115–121. 8. Chiang, R.S.; Syed, A.B.; Wright, J.L. Fenbendazole Enhancing Anti-Tumor Effect: A Case Series. Clin. Oncol. Case Rep. 2021, 4, 2–5. 9. Shaikh, R.; O’Brien, D.P.; Croker, D.M.; Walker, G.M. The development of a pharmaceutical oral solid dosage forms. Comput. Aided Chem. Eng. 2018, 41, 27–65. 10. Bezerra, G.S.N.; Pereira, M.A.V.; Ostrosky, E.A.; Barbosa, E.G.; de Moura, F.V.; Ferrari, M.; Aragão, C.F.S.; Gomes, A.P.B. Compatibility study between ferulic acid and excipients used in cosmetic formulations by TG/DTG, DSC and FTIR. J. Therm. Anal. Calorim. 2017, 127, 1683–1691. [CrossRef] 11. U.S. Department of Health and Human Services Food and Drug Administration. ICH Q8(R2) Pharmaceutical Development. Workshop Qual. By Des. Pharm. 2009, 8, 28. Analytica 2022, 3 460 12. Thakkar, R.; Thakkar, R.; Pillai, A.; Ashour, E.A.; Repka, M.A. Systematic screening of pharmaceutical polymers for hot melt extrusion processing: A comprehensive review. Int. J. Pharm. 2020, 576, 118989. [CrossRef] [PubMed] 13. Ti¸ ta, B.; Fulias, ¸ A.; Bandur, G.; Marian, E.; Ti¸ ta, D. Compatibility study between ketoprofen and pharmaceutical excipients used in solid dosage forms. J. Pharm. Biomed. Anal. 2011, 56, 221–227. [CrossRef] [PubMed] 14. Pereira, M.A.V.; Fonseca, G.D.; Silva-Júnior, A.A.; Fernandes-Pedrosa, M.F.; De, M.; Barbosa, E.G.; Gomes, A.P.B.; dos Santos, K.S.C.R. Compatibility study between chitosan and pharmaceutical excipients used in solid dosage forms. J. Therm. Anal. Calorim. 2014, 116, 1091–1100. [CrossRef] 15. De Barros Lima, Í.P.; Lima, N.G.P.B.; Barros, D.M.C.; Oliveira, T.S.; Mendonҫa, C.M.S.; Barbosa, E.G.; Raffin, F.N.; de Lima e Moura, T.F.A.; Gomes, A.P.B.; Ferrari, M.; et al. Compatibility study between hydroquinone and the excipi- ents used in semi-solid pharmaceutical forms by thermal and non-thermal techniques. J. Therm. Anal. Calorim. 2015, 120, 719–732. [CrossRef] 16. Matos, A.P.S.; Costa, J.S.; Boniatti, J.; Seiceira, R.C.; Pitaluga, A.; Oliveira, D.L.; Viçosa, A.L.; Holandino, C. Compatibility study between diazepam and tablet excipients: Infrared spectroscopy and thermal analysis in accelerated stability conditions. J. Therm. Anal. Calorim. 2017, 127, 1675–1682. [CrossRef] 17. Bezerra, G.S.N.; Colbert, D.M.; O’Donnell, C.; Cao, Z.; Geever, J.; Geever, L. Compatibility Study Between Fenbendazole and Poly(Ethylene Oxide) with Application in Solid Dispersion Formulations Using Hot-Melt Extrusion. J. Pharm. Innov. 2022, 1–13. [CrossRef] 18. Tita, I.C.; Lupa, L.; Tita, B.; Stan, R.L.; Vicas, L. Compatibility Studies of Valsartan with Different Pharmaceutical Excipients. Rev. Chim 2019, 70, 2590–2600. Available online: https://revistadechimie.ro/Articles.asp?ID=7386 (accessed on 1 September 2022). 19. Shakar AA, M.; Hossain, M.J.; Kayesh, R.; Rahman, A.; Sultan, M.Z. Incompatibility of Bisoprolol Fumarate with Some Super- disintegrating Agents. Br. J. Pharm. Res. 2015, 5, 137–145. [CrossRef] 20. Patel, P. Preformulation Studies: An Integral Part of Formulation Design. In Pharmaceutical Formulation Design—Recent Practices; IntechOpen: London, UK, 2020; pp. 1–19. 21. Melian, M.E.; Munguía, A.B.; Faccio, R.; Palma, S.; Domínguez, L. The Impact of Solid Dispersion on Formulation, Using Confocal Micro Raman Spectroscopy as Tool to Probe Distribution of Components. J. Pharm. Innov. 2018, 13, 58–68. [CrossRef] 22. Chadha, R.; Bhandari, S. Drug-excipient compatibility screening-Role of thermoanalytical and spectroscopic techniques. J. Pharm. Biomed. Anal. 2014, 87, 82–97. [CrossRef] 23. Ali, O.T.; Hassan, W.S.; Khayyat, A.N.; Almalki, A.J.; Sebaiy, M.M. HPLC Determination of Imidazoles with Variant Anti-Infective Activity in Their Dosage Forms and Human Plasma. Molecules 2020, 26, 129. [CrossRef] 24. Food and Agriculture Organization of the United Nations. Residues of Some Veterinary Drugs in Foods and Animals 1998. Avail- able online: http://www.fao.org/food/food-safety-quality/scientific-advice/jecfa/jecfa-vetdrugs/details/en/c/26/ (accessed on 1 August 2022). 25. Attia, A.K.; Saad, A.S.; Alaraki, M.S.; Elzanfaly, E.S. Study of thermal analysis behavior of fenbendazole and rafoxanide. Adv. Pharm. Bull. 2017, 7, 329–334. [CrossRef] [PubMed] 26. Rodrigues, L.N.C.; Tavares, A.C.M.; Ferreira, B.T.; Reis, A.K.C.A.; Katiki, L.M. Inclusion complexes and self-assembled cyclodex- trin aggregates for increasing the solubility of benzimidazoles. Braz. J. Pharm. Sci. 2019, 55. [CrossRef] 27. Kolašinac, N.; Kachrimanis, K.; Homšek, I.; Grujic, ´ B.; Uric, ´ Z.; Ibric, ´ S. Solubility enhancement of desloratadine by solid dispersion in poloxamers. Int. J. Pharm. 2012, 436, 161–170. [CrossRef] 28. Woodruff, M.A.; Hutmacher, D.W. The return of a forgotten polymer—Polycaprolactone in the 21st century. Prog. Polym. Sci. 2010, 35, 1217–1256. [CrossRef] 29. Yoganathan, R.; Mammucari, R.; Foster, N.R. Impregnation of Ibuprofen into Polycaprolactone using supercritical carbon dioxide. J. Phys. Conf. Ser. 2010, 2015, 1–5. [CrossRef] 30. Cipriano, T.F.; Da Silva, A.L.N.; Da Fonseca Thomé Da Silva, A.H.M.; De Sousa, A.M.F.; Da Silva, G.M.; Rocha, M.G. Thermal, rheological and morphological properties of poly(Lactic Acid) (PLA) and talc composites. Polimeros 2014, 24, 276–282. 31. Li, D.; Guo, G.; Fan, R.; Liang, J.; Deng, X.; Luo, F.; Qian, Z. PLA/F68/Dexamethasone implants prepared by hot-melt extrusion for controlled release of anti-inflammatory drug to implantable medical devices: I. Preparation, characterization and hydrolytic degradation study. Int. J. Pharm. 2013, 441, 365–372. [CrossRef] 32. Backes, E.H.; de Pires, L.N.; Costa, L.C.; Passador, F.R.; Pessan, L.A. Analysis of the degradation during melt processing of pla/biosilicate®composites. J. Compos. Sci. 2019, 3, 52. [CrossRef] 33. Bezerra, G.S.N.; de Lima, T.A.M.; Colbert, D.M.; Geever, J.; Geever, L. Formulation and Evaluation of Fenbendazole Extended- Release Extrudes Processed by Hot-Melt Extrusion. Polymers 2022, 14, 4188. [CrossRef] 34. Balu, R.; Sampath Kumar, T.S.; Ramalingam, M.; Ramakrishna, S. Electrospun polycaprolactone/Poly(1,4-butylene adipate-co- polycaprolactam) blends: Potential biodegradable scaffold for bone tissue regeneration. J. Biomater. Tissue Eng. 2011, 1, 30–39. [CrossRef] 35. Tanase-Opedal, M.; Espinosa, E.; Rodríguez, A.; Chinga-Carrasco, G. Lignin: A biopolymer from forestry biomass for biocompos- ites and 3D printing. Materials 2019, 12, 3006. [CrossRef] 36. Soto, C.; Otipka, R.; Contreras, D.; Yáñez, J.; Toral, M.I. Co-determination of two antiparasitics drugs by derivative spectropho- tometry and its photodegradation studies. J. Chil. Chem. Soc. 2013, 58, 1824–1829. [CrossRef] Analytica 2022, 3 461 37. Surov, A.O.; Vasilev, N.A.; Vener, M.V.; Parashchuk, O.D.; Churakov, A.V.; Magdysyuk, O.V.; Perlovich, G.L. Pharmaceutical Salts of Fenbendazole with Organic Counterions: Structural Analysis and Solubility Performance. Cryst. Growth Des. 2021, 21, 4516–4530. [CrossRef] 38. Esfahani, M.K.M.; Alavi, S.E.; Cabot, P.J.; Islam, N.; Izake, E.L. Pegylated mesoporous silica nanoparticles (Mcm-41): A promising carrier for the targeted delivery of fenbendazole into prostrate cancer cells. Pharmaceutics 2021, 13, 1605. [CrossRef] [PubMed] 39. Garala, K.; Joshi, P.; Patel, J.; Ramkishan, A.; Shah, M. Formulation and evaluation of periodontal in situ gel. Int. J. Pharm. Investig. 2013, 3, 29. [CrossRef] [PubMed] 40. Chakrapani, V.Y.; Gnanamani, A.; Giridev, V.R.; Madhusoothanan, M.; Sekaran, G. Electrospinning of Type I Collagen and PCL Nanofibers Using Acetic Acid. J. Appl. Polym. Sci. 2012, 125, 3221–3227. [CrossRef] 41. Chieng, B.W.; Ibrahim, N.A.; Yunus, W.M.Z.W.; Hussein, M.Z. Poly(lactic acid)/poly(ethylene glycol) polymer nanocomposites: Effects of graphene nanoplatelets. Polymers 2014, 6, 93–104. [CrossRef] 42. Panicker, C.Y.; Varghese, H.T.; Narayana, B.; Divya, K.; Sarojini, B.K.; War, J.A.; Alsenoy, C.V.; Fun, H.K. FT-IR, NBO, HOMO-LUMO, MEP analysis and molecular docking study of Methyl N-({[2-(2-methoxyacetamido)-4-(phenylsulfanyl)phenyl]amino}[(methoxycarbonyl) imino]methyl)carbamate. Spectrochim. Acta Part A Mol. Biomol. Spectrosc. 2015, 148, 29–42. [CrossRef] 43. Mohan, S.; Sundaraganesan, N.; Mink, J. FTIR and Raman studies on benzimidazole. Spectrochim. Acta Part A Mol. Spectrosc. 1991, 47, 1111–1115. [CrossRef] 44. Pezzoli, R.; Hopkins, M.; Direur, G.; Gately, N.; Lyons, J.G.; Higginbotham, C.L. Micro-injection moulding of poly(Vinylpyrrolidone- vinyl acetate) binary and ternary amorphous solid dispersions. Pharmaceutics 2019, 11, 240. [CrossRef] 45. Siahi, M.R.; Rahimi, S.; Monajjemzadeh, F. Analytical investigation of the possible chemical interaction of methyldopa with some reducing carbohydrates used as pharmaceutical excipients. Adv. Pharm. Bull. 2018, 8, 657–666. [CrossRef] http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Analytica Multidisciplinary Digital Publishing Institute

Compatibility Study between Fenbendazole and Polymeric Excipients Used in Pharmaceutical Dosage Forms Using Thermal and Non-Thermal Analytical Techniques

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Abstract

Article Compatibility Study between Fenbendazole and Polymeric Excipients Used in Pharmaceutical Dosage Forms Using Thermal and Non-Thermal Analytical Techniques Gilberto S. N. Bezerra *, Vicente F. Moritz, Tielidy A. de M. de Lima, Declan M. Colbert, Joseph Geever and Luke Geever * PRISM Research Institute, Technological University of the Shannon: Midlands Midwest, University Road, N37HD68 Athlone, Ireland * Correspondence: a00278630@student.ait.ie (G.S.N.B.); lgeever@ait.ie (L.G) Abstract: The body of work described in this research paper evaluates the compatibility between Fenbendazole (Fen), which is a broad-spectrum anthelmintic with promising antitumor activity, and three polymeric excipients commonly applied in pharmaceutical dosage forms. The assessment of binary mixtures was performed by differential scanning calorimetry and thermogravimetric analysis/derivative thermogravimetry to predict physical and/or chemical interactions, followed by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), and high- performance liquid chromatography (HPLC) to confirm or exclude any interactions. Thermal studies suggested the presence of interactions between Fen and P 407, PCL, and PLA. To validate these data, XRD showed that Fen is compatible with PCL and PLA, suggesting some interaction with P 407. FTIR demonstrated that PCL and PLA can establish physical interactions with Fen; moreover, it suggested Citation: Bezerra, G.S.N.; Moritz, that P 407 interacts not only physically but also chemically, which was later proved by HPLC to be V.F.; de Lima, T.A.d.M.; Colbert, D.M.; only new intermolecular interactions. This work supports the further application of P 407, PCL, and Geever, J.; Geever, L. Compatibility PLA for the development of new medicinal and veterinary formulations containing Fen, since they Study between Fenbendazole and do not affect the physical and chemical characteristics of the active ingredient and consequently its Polymeric Excipients Used in Pharmaceutical Dosage Forms Using bioavailability and therapeutic efficacy. Thermal and Non-Thermal Analytical Techniques. Analytica 2022, 3, 448–461. Keywords: compatibility study; fenbendazole; polymeric excipients https://doi.org/10.3390/ analytica3040031 Academic Editors: Marcello Locatelli 1. Introduction and Victoria Samanidou Methyl N-(6-phenylsulfanyl-1H-benzimidazol-2-yl)carbamate or Fenbendazole (Fen) Received: 25 October 2022 is a member of the benzimidazole family [1]. Fen has a broad spectrum of activities includ- Accepted: 7 December 2022 ing antiparasitic [2], fungicidal [3], antiviral [4], and, particularly, antitumor [5], demon- Published: 12 December 2022 strating a promising effect against different types of cancer, such as skin [6], prostate [7], Publisher’s Note: MDPI stays neutral and kidney [8], with potential application in medicinal and veterinary formulations. with regard to jurisdictional claims in Pharmaceutical dosage forms consist of APIs (active pharmaceutical ingredients) and published maps and institutional affil- suitable excipients, which must be pharmacologically inert, physically and chemically iations. compatible, non-toxic, and not affect the drug’s bioavailability [9]. Hence, the first step for the development of a pharmaceutical formulation should be a preformulation study, which predicts possible incompatibilities between the API and excipients, investigating potential physical and chemical interactions that can compromise the stability, safety, and efficacy of Copyright: © 2022 by the authors. the final product [10]. Furthermore, the U.S. Food and Drug Administration has launched Licensee MDPI, Basel, Switzerland. new regulations establishing drug-excipient compatibility studies as vital for the approval This article is an open access article of new formulations [11]. distributed under the terms and Based on the variety of polymers available and under development, the screening and conditions of the Creative Commons selection of polymers compatible with the API can be challenging. Therefore, new, fast Attribution (CC BY) license (https:// and reliable analytical techniques are required to identify suitable polymeric excipients creativecommons.org/licenses/by/ 4.0/). Analytica 2022, 3, 448–461. https://doi.org/10.3390/analytica3040031 https://www.mdpi.com/journal/analytica Analytica 2022, 3 449 for a new formulation as they play roles such as binders, lubricants, suspending, fillers, solubility enhancers, and stabilizing agents, among other functions [12]. The assessment of binary mixtures using thermoanalytical techniques to predict phys- ical and/or chemical interactions between the API and excipients has been extensively reported [10,13–15]. Differential scanning calorimetry (DSC) and thermogravimetric anal- ysis (TGA) have been the most applied techniques for this purpose. Even though the association of data collected from two thermal techniques such as DSC and TGA enables better characterisation of the events related to a sample, this interpretation must be sup- ported by other analytical techniques, such as X-ray diffraction spectroscopy (XRD), Fourier transformed infrared spectroscopy (FTIR), and high-performance liquid chromatography (HPLC). These techniques have been widely applied to confirm or exclude the events suggested by thermal studies [10,13–19]. Moreover, the application of analytical techniques to quickly and efficiently predict incompatibilities between the API and excipients have a direct impact on the pharmaceuti- cal research and development sectors, avoiding trial and error, preventing raw material wastage, reducing the time required for the development of new formulations, and, conse- quently, decreasing costs [20]. Shakar et al. [19] during the development of a solid dosage form found a low dissolution profile to bisoprolol fumarate and suspected there was some chemical interaction between the API and the disintegrating agents. After HPLC and DSC analysis, they identified that bisoprolol is incompatible with sodium starch glycolate and croscarmellose sodium, which could have been predicted if a prior compatibility study was performed. To the best of our knowledge, there are very few studies predicting physical and/or chemical interactions between Fen and polymeric excipients commonly applied in phar- maceutical dosage forms [17,21]. Therefore, this work aims to study the compatibility between Fen and three polymeric excipients widely applied in drug delivery, namely P 407, PCL, and PLA, using thermal (DSC and TGA/DTG), spectroscopic (XRD and FTIR), and chromatographic (HPLC) techniques. This work is expected to guide the development of new medicinal and veterinary formulations, mainly generic ones, for those in which a careful selection of excipients is required. 2. Materials and Methods 2.1. Materials Fen was purchased from Molekula (Darlington, UK), Tri-block copolymer of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (Kolliphor P 407 Geismar—P 407, Mw 12,000 g mol ) was obtained from BASF (Burgbernheim, Germany), Polycaprolactone ® 1 (CAPA 6506—PCL, Mw 50,000 g mol ) was supplied by Perstorp (Warrington, UK), ® 1 and Poly(lactic acid) (Ingeo 2003D—PLA, Mw 180,477 g mol ) was purchased from NatureWorks (Minnetonka, MN, USA). All other chemicals and reagents were of analytical reagent grade. The chemical structures of Fen and the polymeric excipients used in this study are shown in Figure 1. 2.2. Binary Mixtures Binary mixtures between Fen and each polymeric excipient were prepared in a 1:1 (w/w) ratio with the components mixed using a pestle and mortar. This ratio was chosen to maximize the probability of observing potential interactions [22]. Analytica 2022, 3, FOR PEER REVIEW 3 Analytica 2022, 3 450 Figure 1. Chemical structures of (a) Fen, (b) P 407, (c) PCL, and (d) PLA designed using MarvinSketch 15. 4.6. Figure 1. Chemical structures of (a) Fen, (b) P 407, (c) PCL, and (d) PLA designed using 2.3. Thermal Analyses—DSC and TGA/DTG MarvinSketch 15.4.6. DSC curves were obtained using a Pyris 6 DSC (PerkinElmer, Waltham, MA, USA). Fen thermal characterisation was performed in triplicate using between 6 and 8 mg of the 2.2. Binary Mixtures sample in lid-sealed aluminium pans, under a nitrogen atmosphere with a flow of 30 mL Binary mixtures between Fen and each polymeric excipient were prepared in a 1:1 1  1 min and a heating rate of 10 C min from 40 to 300 C. Calorimetric curves of neat (w/w) ratio with the components mixed using a pestle and mortar. This ratio was chosen polymers and binary mixtures were performed using between 6 and 8 mg of the sample in to maximize the probability of observing potential interactions [22]. lid-sealed aluminium pans, under a nitrogen atmosphere with a flow of 30 mL min and a heating rate of 10 C min from 30 to 300 C. 2.3. Thermal Analyses—DSC and TGA/DTG TGA curves were obtained using a Pyris 1 TGA (PerkinElmer, Waltham, MA, USA). DSC curves were obtained using a Pyris 6 DSC (PerkinElmer, Waltham, MA, USA). Fen was analysed in triplicate using 10 mg of the sample in aluminium pans, under a Fen thermal characterisation was performed in 1triplicate using between  6 and 8 mg 1 of the nitrogen atmosphere with a flow of 20 mL min and a heating rate of 10 C min from 40 sample in lid-sealed aluminium pans, under a nitrogen atmosphere with a flow of 30 mL to 700 C. Thermogravimetric curves of neat polymers and binary mixtures were performed −1 −1 min and a heating rate of 10 °C min from 40 to 300 °C. Calorimetric curves of neat using 10 mg of the sample in aluminium pans, under a nitrogen atmosphere with a flow of 1  1 polymers and binary mixtures were performed using between 6 and 8 mg of the sample 20 mL min and a heating rate of 10 C min from 40 to 700 C. −1 in lid-sealed aluminium pans, under a nitrogen atmosphere with a flow of 30 mL min DSC and TGA/DTG measurements were performed using Pyris—Instrument Manag- −1 and a heating rate of 10 °C min from 30 to 300 °C. ing Software (PerkinElmer, Waltham, MA, USA). TGA curves were obtained using a Pyris 1 TGA (PerkinElmer, Waltham, MA, USA). 2.4. X-ray Diffraction Spectroscopy Fen was analysed in triplicate using 10 mg of the sample in aluminium pans, under a −1 −1 nitrogen atmosphere with a flow of 20 mL min and a heating rate of 10 °C min from 40 Diffractograms were obtained using a Siemens D500 X-ray powder diffractometer to 700 °C. Thermogravimetric curves of neat polymers and binary mixtures were per- (Karlsruhe, Germany) with Cu Ka radiation (l = 0.15418 nm). The 2 (theta) range applied formed using 10 mg of the sample in aluminium pans, under a nitrogen atmosphere with for the test was 10 to 80 . −1 −1 a flow of 20 mL min and a heating rate of 10 °C min from 40 to 700 °C. 2.5. Fourier Transform Infrared Spectroscopy DSC and TGA/DTG measurements were performed using Pyris - Instrument Man- aging Attenuated Software (Perk total inElm reflectance er, Wal Fourier tham, M transform A, USA). infrared spectroscopy (ATR-FTIR) of the samples was carried out on a Perkin Elmer Spectrum (Waltham, MA, USA), with 4 scans 2.4. per X sample, -ray Dif in fra the ction spectral Spectro range scopy from 650 to 4000 cm , and a fixed universal compression force of 85 N. Diffractograms were obtained using a Siemens D500 X-ray powder diffractometer (Karlsruhe, Germany) with Cu Kα radiation (λ = 0.15418 nm). The 2θ (theta) range applied 2.6. High-Performance Liquid Chromatography for the test was 10° to 80°. HPLC analysis was carried out using a system consisting of a Waters Alliance e2695 separations module combined with a Waters 2487 dual  absorbance detector (Waters 2.5. Fourier Transform Infrared Spectroscopy Chromatography Ireland Ltd., Dublin, Ireland). The chromatographic analyses of neat Fen Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) of and binary mixtures were performed using the protocol published by Ali et al. [23] with the samples was carried out on a Perkin Elmer Spectrum (Waltham, MA, USA), with 4 minor modifications. A Thermo Scientific BDS Hypersil C8 column (250 mm  4.60 mm, −1 scans per sample, in the spectral range from 650 to 4000 cm , and a fixed universal com- 5 m) (Fisher Scientific Ireland Ltd., Dublin, Ireland) maintained at ambient temperature pression force of 85 N. was used as the stationary phase. The mobile phase consisted of methanol and 0.025 M monopotassium phosphate (70:30 v/v) adjusted to pH 3.20 using ortho-phosphoric acid, Analytica 2022, 3, FOR PEER REVIEW 4 2.6. High-Performance Liquid Chromatography HPLC analysis was carried out using a system consisting of a Waters Alliance e2695 separations module combined with a Waters 2487 dual λ absorbance detector (Waters Chromatography Ireland Ltd, Dublin, Ireland). The chromatographic analyses of neat Fen and binary mixtures were performed using the protocol published by Ali et al. [23] with minor modifications. A Thermo Scientific BDS Hypersil C8 column (250 mm × 4.60 mm, 5 µ m) (Fisher Scientific Ireland Ltd, Dublin, Ireland) maintained at ambient temperature Analytica 2022, 3 451 was used as the stationary phase. The mobile phase consisted of methanol and 0.025 M monopotassium phosphate (70:30 v/v) adjusted to pH 3.20 using ortho-phosphoric acid, −1 filtered, and degassed. A flow rate of 1 mL min was maintained during the procedure, filtered, and degassed. A flow rate of 1 mL min was maintained during the procedure, the detector was set at 288 nm, and the sample injection volume was 10 µ L. Further anal- the detector was set at 288 nm, and the sample injection volume was 10 L. Further analyses yses were performed using Empower software. were performed using Empower software. 3. Results 3. Results 3.1. Thermal Characterisation of Fenbendazole 3.1. Thermal Characterisation of Fenbendazole Figure 2 shows the DSC curves of Fen characterised by a sharp endothermic peak at Figure 2 shows the DSC curves of Fen characterised by a sharp endothermic peak at −1 244 °C  (ΔH = 252 J g ) 1corresponding to the melting point, followed by decomposition at 244 C (DH = 252 J g ) corresponding to the melting point, followed by decomposition −1 271 °C (ΔH = 27 J g ). Though the literature reports the same calorimetric pattern of melt- at 271 C (DH = 27 J g ). Though the literature reports the same calorimetric pattern of ing followed by decomposition [24], there is a lack of consensus about the Fen melting melting followed by decomposition [24], there is a lack of consensus about the Fen melting temperature (Tm) because it relies on the heating rate applied, nitrogen flow rate, and other temperature (T ) because it relies on the heating rate applied, nitrogen flow rate, and other parameters. For instance, Attia et al. [25] identified the melting peak of Fen at 230 °C, parameters. For instance, Attia et al. [25] identified the melting peak of Fen at 230 C, Rodrigues et al. [26] at 214 °C, and Melian et al. [21] at 210 °C. Rodrigues et al. [26] at 214 C, and Melian et al. [21] at 210 C. −1 Figure 2. DSC curve of Fen at a heating rate of 10 °C min .1 Figure 2. DSC curve of Fen at a heating rate of 10 C min . In Figure 3, the TGA/DTG curves demonstrate that Fen is stable below 164 °C fol- In Figure 3, the TGA/DTG curves demonstrate that Fen is stable below 164 C followed lowed by four main stages of degradation. The first stage of mass loss is from 164 to 269 by four main stages of degradation. The first stage of mass loss is from 164 to 269 C °C (∆m = 13%) with Tpeak DTG = 241 °C, the second is from 270 to 357 °C (∆m = 8%) with (Dm = 13%) with T DTG = 241 C, the second is from 270 to 357 C (Dm = 8%) with peak Tpeak DTG = 334 °C, the third is from 358 to 506 °C (∆m = 34%) with Tpeak DTG = 428 °C, and T DTG = 334 C, the third is from 358 to 506 C (Dm = 34%) with T DTG = 428 C, peak peak th and e las the t is last frois m fr 507 omto 507 700 to °C 700 (∆m C= (34% Dm ) =w 34%) ith Twith peak DTG T = 67 DTG 2 °C = . Th 672 e di C. ffe The rencdif e in fer ma ence ss peak loss in mass (∆m loss = 11%) (Dm corre = 11%) spon corr ds to esponds the carbon to the aceou carbonaceous s residue. Si rm esidue. ilar resu Similar lts were results described were in described the literain ture the by literatur Attia et eal. by [25] Attia . Thet ey al. describe [25]. d They that described Fen is stable that up Fen to 179 is stable °C followed up to by 179fou Cr followed stages of by mass four loss stages . The fi of rst mass stage loss. is bet The ween first 179 stage and is 24 between 5 °C (∆m 179 = 10% and ) char 245 ac- C (Dm = 10%) characterised by the loss of the sulphur atom, the second is between 245 and terised by the loss of the sulphur atom, the second is between 245 and 345 °C (∆m = 10%) 345 C (Dm = 10%) represented by the loss of CH O, the third is between 345 and 461 C represented by the loss of CH3O, the third is between 345 and 461 °C (∆m = 35%) associated (Dm = 35%) associated with the loss of C H and CO molecules, and the last one is between with the loss of C6H5 and CO molecule6 s, and 5 the last one is between 461 and 746 (∆m = 461 and 746 (Dm = 43%) represented by the loss of the C H N molecule. 43%) represented by the loss of the C7H5N3 molecule. 7 5 3 After the API thermal characterisation, it is reasonable to evaluate its physical and chemical interactions with the polymeric excipients since the incompatibility between them can affect the pharmaceutical dosage form properties, and, consequently, the therapeutic efficacy [14]. Therefore, it is required to analyse the DSC and TGA/DTG curves of each neat ingredient followed by their comparison with the curves of the binary mixtures to identify possible alterations of the API thermal behaviour. Analytica 2022, 3 452 Analytica 2022, 3, FOR PEER REVIEW 5 −1 Figure 3. TGA/DTG curves of Fen at a heating rate of 10 °C min . Figure 3. TGA/DTG curves of Fen at a heating rate of 10 C min . 3.2. Thermal After thAnalysis e API thof ermal the Physical characteri Mixtur sation es by , it DSC is reason and TGA/DTG able to evaluate its physical and chemical interactions with the polymeric excipients since the incompatibility between Figures 4–6 show the calorimetric and thermogravimetric curves of neat Fen, neat poly- them can affect the pharmaceutical dosage form properties, and, consequently, the thera- meric excipients, and physical mixtures with all the thermal events numerically described peutic efficacy [14]. Therefore, it is required to analyse the DSC and TGA/DTG curves of in Table 1. each neat ingredient followed by their comparison with the curves of the binary mixtures Table 1. Thermoanalytical data of neat excipients and physical mixtures between Fen + polymeric to identify possible alterations of the API thermal behaviour. excipients 1:1 (w/w) at a heating rate of 10 C min . 3.2. Thermal Analysis of the Physical Mixtures by DSC and TGA/DTG DSC TGA DTG Figures 4–6 show the calorimetric and thermogravimetric curves of neat Fen, neat Excipients Transition T [ C] T [ C] DT [ C] Dm [%] T [ C] DH [J g ] onset m peak polymeric excipients, and physical mixtures with all the thermal events numerically de- 1st Endo 51 57 185 scribed in Table 1. P 407 146–398 96 288 1st Endo 55 63 112 233–470 92 409 PCL Table 1. Thermoanalytical data of neat excipients and physical mixtures between Fen + polymeric 471–547 6 514 −1 excipients 1:1 (w/w) at a heating rate of 10 °C min . 1st Endo 145 152 48 PLA 286–411 98 378 DSC TGA DTG −1 a Excipients Transition Tonset [° C] Tm [° C] ΔH [J g ] ∆T [° C] ∆m [%] Tpeak [° C] Physical 1  a Transition T [ C] T [ C] DT [ C] Dm [%] T [ C] onset m DH [J g ] peak 1st Endo 51 57 185 mixtures P 407 146–398 96 288 1st Endo 52 58 88 1st Endo 55 63 112 2nd Endo 219 236 46 142–301 11 233 PCL 233–470 92 409 Fen + P 407 3rd Endo 268 283 17 302–339 5 319 471–547 6 514 340–480 52 378 1st Endo 145 152 48 PLA 481–700 28 615 286–411 98 378 1st Endo 56 62 54 −1 a Physical mixtures Transition Tonset [° C] Tm [° C] ΔH [J g ] ∆T [° C] ∆m [%] Tpeak [° C] 2nd Endo 217 235 71 140–274 6 230 1st Endo 52 58 88 Fen + PCL 3rd Endo 268 283 12 275–433 63 398 2nd Endo 219 236 46 142–301 11 233 434–497 6 462 Fen + P 407 3rd Endo 268 283 17 302–339 5 319 498–700 22 591 340–480 52 378 1st Endo 143 148 3 2nd Endo 225 232 100 173–234 481–700 2 28 216 615 1st Endo246 56 250 62 2 54 235–259 2 239 Fen + PLA 3rd Endo 2nd Endo 217 235 71 140–274 6 230 260–449 78 320 3rd Endo 268 283 12 450–700 275–433 15 63 604 398 Fen + PCL 434–497 6 462 DT ranges between T and T onset endset. 498–700 22 591 1st Endo 143 148 3 2nd Endo 225 232 100 173–234 2 216 Fen + PLA 3rd Endo 246 250 2 235–259 2 239 260–449 78 320 450–700 15 604 ∆T ranges between Tonset and Tendset. Analytica 2022, 3, FOR PEER REVIEW 6 Analytica 2022, 3 453 Figure 4. Thermal behaviour of P 407—DSC (a), TGA (b), and DTG (c) at a heating rate of Figure 4. Thermal behaviour of P 407—DSC (a), TGA (b), and DTG (c) at a heating rate of 10 °C 1 −1 10 C min . Fen min (red), . Fen neat (redpolymer ), neat polym (black), er (blac and k), physical and physic mixtur al mixtur e (blue). e (blue). In general, the calorimetric curve of Fen displays a well-defined endothermic peak characteristic of fusion at 244 C (DH = 252 J g ). Hence, any displacement or disap- pearance of this peak and/or a degree of variation in enthalpy values can indicate either physical or chemical interactions [13,17]. P 407 (Figure 4a) shows a single endothermic peak characteristic of the polymer melt- ing at 57 C (DH = 185 J g ), which matches with another study [27]. The calorimetric curve of the physical mixture shows three endothermic peaks at 58 C (DH = 88 J g ), 1  1 236 C (DH = 46 J g ), and 283 C (DH = 17 J g ), with an expressive reduction of Fen melting peak anticipated by 8 C. The TGA curve (Figure 4b) demonstrates a decrease of Fen thermal stability from 164 to 142 C, representing 22 C. Kolašinac et al. [27] studied physical mixtures between poloxamer 407 and desloratadine; they reported that the poly- mer melting point remained unchanged but the desloratadine melting peak shifted to a lower temperature, suggesting an interaction between them. Analytica 2022, 3 Analytica 2022, 3, FOR PEER REVIEW 454 7 Figure 5. Thermal behaviour of PCL—DSC (a), TGA (b), and DTG (c) at a heating rate of 10 C min . −1 Figure 5. Thermal behaviour of PCL—DSC (a), TGA (b), and DTG (c) at a heating rate of 10 °C min . Fen (red), neat polymer (black), and physical mixture (blue). Fen (red), neat polymer (black), and physical mixture (blue). PCL (Figure 5a) displays a single endothermic peak characteristic of the polymer melting at 63 C (DH = 112 J g ), which agrees with the literature [28]. The DSC curve of the binary mixture displays three endothermic peaks at 62 C (DH = 54 J g ), 235 C 1  1 (DH = 71 J g ), and 283 C (DH = 12 J g ), with reduction of Fen melting peak and anticipation of 9 C. The thermogravimetric curve (Figure 5b) shows a decrease in Fen thermal stability of 24 C from 164 to 140 C. In another study conducted by Yoganathan and Mammucar [29], they also reported a shift of the ibuprofen melting point when loaded in PCL, but their TGA analysis showed no alteration of the drug thermal degradation. Analytica 2022, 3, FOR PEER REVIEW 8 Analytica 2022, 3 455 Figure 6. Thermal behaviour of PLA—DSC (a), TGA (b), and DTG (c) at a heating rate of −1 Figure 6. Thermal behaviour of PLA—DSC (a), TGA (b), and DTG (c) at a heating rate of 10 °C min . 10 C min . Fen Fen (red), (red), neat neat polymer polymer ( (black), black), and and ph physical ysical mmixtur ixture (blue). e (blue). PLA (Figure 6a) In demonstrates general, the calo arimetric glass transition curve of Fen (T dis ) at pl63 ays C a w followed ell-defined byendot a melting hermic peak 1 −1 characteristic of fusion at 244 °C (ΔH = 252 J g ). Hence, any displacement or disappear- peak at 152 C (DH = 48 J g ) as described in other studies [30–32]. The calorimetric ance of this peak and/or a degree of variation in enthalpy values can indicate either phys- curve of the physical mixture presents three endothermic peaks at 148 C (DH = 3 J g ), ical or chem 1 ical interactions [13,17]. 1 232 C (DH = 100 J g ), and 250 C (DH = 2 J g ) followed by not only a reduction of Fen P 407 (Figure 4a) shows a single endothermic peak characteristic of the polymer melt- melting peak but also an anticipation of 12 C. The thermogravimetric curve (Figure 6b) −1 ing at 57 °C (ΔH = 185 J g ), which matches with another study [27]. The calorimetric curve displays an increase in Fen thermal stability of 9 C from 164 to 173 C. Li et al. [31], who −1 of the physical mixture shows three endothermic peaks at 58 °C (ΔH = 88 J g ), 236 °C (ΔH studied PLA and dexamethasone, also reported a decrease in the API melting point, but it −1 −1 = 46 J g ), and 283 °C (ΔH = 17 J g ), with an expressive reduction of Fen melting peak did not affect the drug properties. anticipated by 8 °C. The TGA curve (Figure 4b) demonstrates a decrease of Fen thermal After analysing the calorimetric curves, we can see that all physical mixtures display stability from 164 to 142 °C, representing 22 °C. Kolašinac et al. [27] studied physical three endothermic peaks; the first one is attributed to the respective polymer melting transition, the second to Fen melting point, and the third is characteristic of decomposition. All polymeric excipients under study had some impact on Fen thermal behaviour, which can be mainly described as follows: (i) shifting the melting point, (ii) decreasing the melting peak area and height becoming broadened and lowered, and (iii) reducing the enthalpy of Analytica 2022, 3 456 fusion. This is an indication of interaction between Fen and each polymeric excipient, but it must be studied by other analytical techniques, such as XRD, FTIR, and HPLC, to confirm or exclude it. 3.3. Physical and Chemical Analysis of the Mixtures by XRD, FTIR, and HPLC To further investigate any possible interactions between Fen and each polymeric excipient, XRD, FTIR and HPLC were employed in this study through qualitative analyses to obtain more information to support the DSC and TGA/DTG results. The results obtained from Fen diffractogram (Figure 7) reveal its crystalline character- istics with seven well-evidenced peaks appearing at 2 = 10.40, 12.59, 17.57, 25.31, 25.81, 26.50, and 30.98 with similar results found in the literature [21,33]. After analysing each neat polymeric excipient, their diffractograms revealed the following: P 407 displayed two main signals at 2 = 18.73 and 23.81 (Figure 7a) [21]; PCL exhibited two peaks at 2 = 20.70 and 23.19 (Figure 7b) [34]; and PLA showed a broad diffraction peak associated with its Analytica 2022, 3, FOR PEER REVIEW 10 amorphous regions at 2 = 10–25 , which likely covered up the crystalline domains’ peaks (Figure 7c), as the DSC analysis proved the existence of crystallinity due to the appearance of the polymer melting peak at 152 C [35]. Figure 7. XRD shows the main diffraction peaks characteristic of neat Fen followed by physical Figure 7. XRD shows the main diffraction peaks characteristic of neat Fen followed by physical mix- mixtures between Fen and (a) P 407, (b) PCL, and (c) PLA. FTIR shows the main signals characteristic tures between Fen and (a) P 407, (b) PCL, and (c) PLA. FTIR shows the main signals characteristic of neat Fen followed by physical mixtures between fen and (d) P 407, (e) PCL, and (f) PLA. Fen (red), of neat Fen followed by physical mixtures between fen and (d) P 407, (e) PCL, and (f) PLA. Fen neat polymers (black), and physical mixtures (blue). (red), neat polymers (black), and physical mixtures (blue). X-ray diffraction patterns obtained from the physical mixtures are virtually the simple X-ray diffraction patterns obtained from the physical mixtures are virtually the sim- superposition of the patterns corresponding to the crystalline phase of each component of ple superposition of the patterns corresponding to the crystalline phase of each compo- the mixture. Despite not seeing any additional crystalline peak, P 407 led to a reduction of nent of the mixture. Despite not seeing any additional crystalline peak, P 407 led to a re- some of the main diffraction peaks of the API, such as 2 = 17.57, 25.31, 25.81 and 26.50 , duction of some of the main diffraction peaks of the API, such as 2θ = 17.57, 25.31, 25.81 which indicates some type of interaction between them. Therefore, further investigation and 26.50°, which indicates some type of interaction between them. Therefore, further in- with FTIR is required to exclude any incompatibility since there is the possibility of a vestigation with FTIR is required to exclude any incompatibility since there is the possi- chemical interaction happening between the amorphous regions of the components, which bility of a chemical interaction happening between the amorphous regions of the compo- would not be noticeable by XRD. nents, which would not be noticeable by XRD. The FTIR spectrum of Fen was confirmed by comparison with SpectraBase—Wiley The FTIR spectrum of Fen was confirmed by comparison with SpectraBase—Wiley (43210-67-9), which allowed the identification of its absorption bands. Figure 7 shows the (43210-67-9), which allowed the identification of its absorption bands. Figure 7 shows the main infrared signals characteristic of Fen at 3336 cm assigned to the (N-H) stretching −1 main infrared signals characteristic of Fen at 3336 cm assigned to the (N-H) stretching mode from the carbamate group, 1630 cm attributed to the (N-H) bending and the −1 mode from the carbamate group, 1630 cm attributed to the (N-H) bending and the (C-N) 1 1 (C-N) stretching modes, 742 cm assigned to the (phenyl), and 685 cm attributed −1 −1 stretching modes, 742 cm assigned to the (phenyl), and 685 cm attributed to the (ben- zenethiol) [21,36–38]. Other less relevant infrared signals are described in the literature −1 −1 such as 3050–2954 cm attributed to the (C-H) tension mode, 2650 cm assigned to the (N- −1 H) stretching mode of the benzimidazole ring, 1708 cm attributed to the (C=O) stretching −1 −1 vibrations of the carbamate carbonyl, 1442 cm assigned to the (C-N), 1222 cm attributed −1 to the (C-O), and 1099 cm attributed to the phenyl-(o) [36,37]. After analysing the infrared profile of Fen, we studied the spectrum of each poly- meric excipient to compare them to the spectra of their physical mixtures. The P 407 spec- trum (Figure 7d) demonstrates three main infrared signals identified by (C-H) stretching −1 −1 aliphatic at 2882 cm , (in-plane O-H) bending at 1343 cm , and (C-O) stretching at 1100 −1 cm [39]. The PCL spectrum (Figure 7e) can be characterised by (CH2) vibrations at 2946, −1 −1 2870, and 2821 cm , (C=O) vibrations with a sharp intense peak at 1728 cm , (CH2) bend- −1 −1 ing vibrations at 1465, 1407, and 1362 cm , (COO) vibrations at 1238 and 1181 cm , as well −1 as (C-O) vibrations at 1099 and 1047 cm [40]. The PLA spectrum (Figure 7f) can be iden- −1 −1 tified by stretching frequencies of (C=O) at 1746 cm , (CH3) asymmetric at 2995 cm , (CH3) −1 −1 symmetric at 2946 cm , (C-O) at 1080 cm , and bending frequencies for (CH3) asymmetric −1 −1 at 1452 cm and (CH3) symmetric at 1361 cm [41]. Analytica 2022, 3 457 to the (benzenethiol) [21,36–38]. Other less relevant infrared signals are described in 1 1 the literature such as 3050–2954 cm attributed to the (C-H) tension mode, 2650 cm assigned to the (N-H) stretching mode of the benzimidazole ring, 1708 cm attributed to the (C=O) stretching vibrations of the carbamate carbonyl, 1442 cm assigned to the (C-N), 1 1 1222 cm attributed to the (C-O), and 1099 cm attributed to the phenyl-(o) [36,37]. After analysing the infrared profile of Fen, we studied the spectrum of each polymeric excipient to compare them to the spectra of their physical mixtures. The P 407 spectrum (Figure 7d) demonstrates three main infrared signals identified by (C-H) stretching aliphatic 1 1 1 at 2882 cm , (in-plane O-H) bending at 1343 cm , and (C-O) stretching at 1100 cm [39]. The PCL spectrum (Figure 7e) can be characterised by (CH ) vibrations at 2946, 2870, 1 1 and 2821 cm , (C=O) vibrations with a sharp intense peak at 1728 cm , (CH ) bending Analytica 2022, 3, FOR PEER REVIEW 211 1 1 vibrations at 1465, 1407, and 1362 cm , (COO) vibrations at 1238 and 1181 cm , as well as (C-O) vibrations at 1099 and 1047 cm [40]. The PLA spectrum (Figure 7f) can be 1 1 identified by stretching frequencies of (C=O) at 1746 cm , (CH ) asymmetric at 2995 cm , All the exclusive signals responsible for characterising the API were present without 1 1 (CH ) symmetric at 2946 cm , (C-O) at 1080 cm , and bending frequencies for (CH ) 3 3 the appearance of new ones for the binary mixtures of Fen with PCL and PLA. In general, 1 1 asymmetric at 1452 cm and (CH ) symmetric at 1361 cm [41] any decrease of the components’ main peaks can be a consequence of dilution, mainly All the exclusive signals responsible for characterising the API were present without when working with a drug and polymer ratio of 1:1; furthermore, subtle differences be- the appearance of new ones for the binary mixtures of Fen with PCL and PLA. In general, tween spectra can indicate the presence of intermolecular interactions between Fen and any decrease of the components’ main peaks can be a consequence of dilution, mainly when each polymeric excipient, which is a characteristic of physical interactions [27]. working with a drug and polymer ratio of 1:1; furthermore, subtle differences between By evaluating the whole spectrum of the physical mixture between Fen and P 407 spectra can indicate the presence of intermolecular interactions between Fen and each −1 (Figure 8), we identified the disappearance of a signal at 1125 cm , the appearance of a polymeric excipient, which is a characteristic of physical interactions [27]. −1 −1 new one at 996 cm , followed by two small “shoulders” at 730 and 703 cm . These two By evaluating the whole spectrum of the physical mixture between Fen and P 407 small “shoulders” were present in the spectra of all physical mixtures, but th 1 e literature (Figure 8), we identified the disappearance of a signal at 1125 cm , the appearance of −1 −1 1 1 describes these signals at 730 cm as the in-plane bending mode (C=O) [42] and 703 cm a new one at 996 cm , followed by two small “shoulders” at 730 and 703 cm . These as the carbon out-of-plane bending vibration mode of benzene [43], which clearly are two small “shoulders” were present in the spectra of all physical mixtures, but the liter- physical interactions. Nevertheless, P 407 was the only polymer missing a signal, more ature describes these signals at 730 cm as the in-plane bending mode (C=O) [42] and −1 specifically the one at 1125 cm , which the literature suggests to be interpreted as asym- 703 cm as the carbon out-of-plane bending vibration mode of benzene [43], which clearly metric (C-O-C) stretching vibrations or (C-N) stretching mode representing a physical in- are physical interactions. Nevertheless, P 407 was the only polymer missing a signal, 1 −1 teraction, followed by the presence of a new signal at 996 cm , which is suggestive of a more specifically the one at 1125 cm , which the literature suggests to be interpreted as chemical interaction [42]. asymmetric (C-O-C) stretching vibrations or (C-N) stretching mode representing a physical interaction, followed by the presence of a new signal at 996 cm , which is suggestive of a chemical interaction [42]. Figure 8. Spectral comparison among Fen (red), neat P 407 (black), and physical mixture be- Figure 8. Spectral comparison among Fen (red), neat P 407 (black), and physical mixture between tween Fen and P 407 (blue) to pinpoint the disappearance and appearance of new peaks in the Fen and P 407 (blue) to pinpoint the disappearance and appearance of new peaks in the mixture mixture spectrum. spectrum. Melian et al. [21] evaluated the mixture between Fen and P 407, analysing their most relevant signals and reporting no visible alteration suggestive of a chemical interaction. Contrastingly, Kolašinac et al. [27] described that the spectra of the physical mixture be- tween desloratadine and P 407 are largely similar to the spectra of each component with subtle differences, indicating the existence of intermolecular interactions between them probably due to the formation of hydrogen bonds characterising a physical interaction. In another study, Pezzoli el at. [44] attributed the appearance of a new band in the spectra of their formulations to the occurrence of new intermolecular interactions. Thus, this new band in the spectra of our physical mixture between Fen and P 407 can very likely be justified by the establishment of new intermolecular interactions between drug–polymer. In a preformulation study conducted by Siahi et al. [45], HPLC proved to be an effi- cient qualitative method to confirm the incompatibility between Methyldopa and some pharmaceutical excipients through the presence of a new peak in the chromatograms of Analytica 2022, 3 458 Melian et al. [21] evaluated the mixture between Fen and P 407, analysing their most relevant signals and reporting no visible alteration suggestive of a chemical interaction. Contrastingly, Kolašinac et al. [27] described that the spectra of the physical mixture between desloratadine and P 407 are largely similar to the spectra of each component with subtle differences, indicating the existence of intermolecular interactions between them probably due to the formation of hydrogen bonds characterising a physical interaction. In another study, Pezzoli el at. [44] attributed the appearance of a new band in the spectra of their formulations to the occurrence of new intermolecular interactions. Thus, this new band in the spectra of our physical mixture between Fen and P 407 can very likely be Analytica 2022, 3, FOR PEER REVIEW justified by the establishment of new intermolecular interactions between drug–polymer 12. In a preformulation study conducted by Siahi et al. [45], HPLC proved to be an efficient qualitative method to confirm the incompatibility between Methyldopa and some pharmaceutical excipients through the presence of a new peak in the chromatograms of the binary mixtures. Figure 9 shows the HPLC chromatogram of neat Fen (a) followed by the binary mixtures. Figure 9 shows the HPLC chromatogram of neat Fen (a) followed binary mixtures of Fen and P 407 (b), PCL (c), and PLA (d). HPLC endorses the thermal by binary mixtures of Fen and P 407 (b), PCL (c), and PLA (d). HPLC endorses the and spectroscopic assays indicating the compatibility of the API with PCL, PLA, as well thermal and spectroscopic assays indicating the compatibility of the API with PCL, PLA, as as P 407 without the appearance of new peaks that could support the possibility of chem- well as P 407 without the appearance of new peaks that could support the possibility of ical interactions. chemical interactions. Figure 9. HPLC chromatogram of (a) neat Fen—retention time: 6.81, followed by physical mixtures Figure 9. HPLC chromatogram of (a) neat Fen—retention time: 6.81, followed by physical mixtures between Fen and (b) P 407—6.84 min, (c) PCL—6.84 min, and (d) PLA—6.80 min. between Fen and (b) P 407—6.84 min, (c) PCL—6.84 min, and (d) PLA—6.80 min. Therefore, it can be concluded that the thermal, spectroscopic, and chromatographic Therefore, it can be concluded that the thermal, spectroscopic, and chromatographic assays reported here attest to the physical and chemical compatibility of Fen with P 407, assays reported here attest to the physical and chemical compatibility of Fen with P 407, PCL, and PLA. PCL, and PLA. 4. 4. Co Conclusions nclusions Thermoanalytical techniques such as DSC and TGA/DTG with the support of XRD, Thermoanalytical techniques such as DSC and TGA/DTG with the support of XRD, FTIR, and HPLC have proved herein to be fast and efficient methods for predicting physical FTIR, and HPLC have proved herein to be fast and efficient methods for predicting phys- and/or chemical interactions between Fen and polymeric excipients. ical and/or chemical interactions between Fen and polymeric excipients. Thermal studies suggested the possibility of interactions between Fen and the poly- Thermal studies suggested the possibility of interactions between Fen and the poly- meric excipients due to their capacity of shifting the Fen melting point, decreasing the meric excipients due to their capacity of shifting the Fen melting point, decreasing the melting peak area and height, and reducing the enthalpy of fusion, which can be attributed melting peak area and height, and reducing the enthalpy of fusion, which can be at- to the capacity of the polymers to dissolve part of the Fen crystalline structure during tributed to the capacity of the polymers to dissolve part of the Fen crystalline structure DSC measurements or even due to the heterogeneity in the small samples [13]. To validate during DSC measurements or even due to the heterogeneity in the small samples [13]. To these data, XRD analysis showed that Fen is compatible with PCL and PLA since its main validate these data, XRD analysis showed that Fen is compatible with PCL and PLA since diffraction peaks remained unchanged in the physical mixture, but it suggested some inter- its main diffraction peaks remained unchanged in the physical mixture, but it suggested action with P 407. FTIR proved that PCL and PLA do not have any incompatibility that can some interaction with P 407. FTIR proved that PCL and PLA do not have any incompati- compromise Fen properties. On the other hand, P 407 demonstrated a physical interaction bility that can compromise Fen properties. On the other hand, P 407 demonstrated a phys- ical interaction with Fen possibly by hydrogen bonds and/or hydrophobic interactions; furthermore, we suspected a chemical interaction between them due to the appearance of a new signal, which was later proved by HPLC to be only new intermolecular interactions. In general, a physical interaction can result in polymorphism formation, change the polymorphic form, and lead to the API solubilization with the excipient creating intermo- lecular interactions between their functional groups; nevertheless, it is not considered an incompatibility if the excipient does not change the physical-chemical properties of the API [10]. Thus, these results support the further application of P 407, PCL, and PLA in the development of medicinal and veterinary formulations containing Fen since they do not affect the physical and chemical characteristics of the active ingredient, and consequently its bioavailability and therapeutic efficacy. Moreover, this preformulation study using Analytica 2022, 3 459 with Fen possibly by hydrogen bonds and/or hydrophobic interactions; furthermore, we suspected a chemical interaction between them due to the appearance of a new signal, which was later proved by HPLC to be only new intermolecular interactions. In general, a physical interaction can result in polymorphism formation, change the polymorphic form, and lead to the API solubilization with the excipient creating inter- molecular interactions between their functional groups; nevertheless, it is not considered an incompatibility if the excipient does not change the physical-chemical properties of the API [10]. Thus, these results support the further application of P 407, PCL, and PLA in the development of medicinal and veterinary formulations containing Fen since they do not affect the physical and chemical characteristics of the active ingredient, and consequently its bioavailability and therapeutic efficacy. Moreover, this preformulation study using thermal and non-thermal analytical techniques can be a starting tool for the screening of other suitable polymeric excipients for the development of new pharmaceutical formulations to carry Fen, particularly generic ones, for those in which a careful selection of excipients is required. Author Contributions: Conceptualization, G.S.N.B.; methodology, G.S.N.B.; formal analysis, G.S.N.B. and V.F.M.; investigation, G.S.N.B.; resources, J.G. and L.G.; data curation, G.S.N.B. and V.F.M.; writing—original draft preparation, G.S.N.B.; writing—review and editing, G.S.N.B., V.F.M. and T.A.d.M.d.L.; visualization, G.S.N.B., V.F.M. and T.A.d.M.d.L.; supervision, D.M.C., J.G. and L.G.; project administration, G.S.N.B., D.M.C., J.G. and L.G.; funding acquisition, G.S.N.B., D.M.C., J.G. and L.G. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by the Irish Research Council (IRC), grant number GOIPG/2022/ 1734 and the President Seed Fund from TUS: Midlands and Midwest, grant number PA01007. Acknowledgments: The authors would like to express their gratitude to Daniel Pádraig Fitzpatrick for his support with the FTIR, Lynn Louis for her assistance with the HPLC as well as the technical support of the staff from the Centre for Industrial Services Design (CISD) and Applied Polymer Technologies (APT). Conflicts of Interest: The authors declare no conflict of interest. References 1. National Center for Biotechnology Information. PubChem Compound Summary for CID 3334, Fenbendazole. 2021. Available online: https://pubchem.ncbi.nlm.nih.gov/compound/Fenbendazole (accessed on 1 August 2022). 2. Goossens, E.; Dorny, P.; Vercammen, F.; Vercruysse, J. Field evaluation of the efficacy of fenbendazole in captive wild ruminants. Vet. Record 2005, 157, 582–586. [CrossRef] [PubMed] 3. de Oliveira, H.C.; Joffe, L.S.; Simon, K.S.; Castelli, R.F.; Reis, F.C.G.; Bryan, A.M.; Borges, B.S.; Medeiros, L.C.S.; Bocca, A.L.; Del Poeta, M.; et al. Fenbendazole controls in vitro growth, virulence potential, and animal infection in the Cryptococcus model. Antimicrob. Agents Chemother. 2020, 64, 1–14. [CrossRef] [PubMed] 4. Chang, L.; Zhu, L. Dewormer drug fenbendazole has antiviral effects on BoHV-1 productive infection in cell cultures. J. Vet. Sci. 2020, 21, 1–10. [CrossRef] [PubMed] 5. Duan, Q.; Liu, Y.; Rockwell, S. Fenbendazole as a potential anticancer drug. Anticancer Res. 2013, 33, 355–362. 6. Movahedi, F.; Gu, W.; Soares, C.P.; Xu, Z.P. Encapsulating Anti-Parasite Benzimidazole Drugs into Lipid-Coated Calcium Phosphate Nanoparticles to Efficiently Induce Skin Cancer Cell Apoptosis. Front. Nanotechnol. 2021, 3, 1–13. [CrossRef] 7. Aycock-Williams, A.; Pham, L.; Liang, M.; Adisetiyo, H.A.; Geary, L.A.; Cohen, M.B.; Casebolt, D.B.; Roy-Burman, P. Effects of fenbendazole and vitamin E succinate on the growth and survival of prostate cancer cells. J. Cancer Res. Exp. Oncol. 2011, 3, 115–121. 8. Chiang, R.S.; Syed, A.B.; Wright, J.L. Fenbendazole Enhancing Anti-Tumor Effect: A Case Series. Clin. Oncol. Case Rep. 2021, 4, 2–5. 9. Shaikh, R.; O’Brien, D.P.; Croker, D.M.; Walker, G.M. The development of a pharmaceutical oral solid dosage forms. Comput. Aided Chem. Eng. 2018, 41, 27–65. 10. Bezerra, G.S.N.; Pereira, M.A.V.; Ostrosky, E.A.; Barbosa, E.G.; de Moura, F.V.; Ferrari, M.; Aragão, C.F.S.; Gomes, A.P.B. Compatibility study between ferulic acid and excipients used in cosmetic formulations by TG/DTG, DSC and FTIR. J. Therm. Anal. Calorim. 2017, 127, 1683–1691. [CrossRef] 11. U.S. Department of Health and Human Services Food and Drug Administration. ICH Q8(R2) Pharmaceutical Development. Workshop Qual. By Des. Pharm. 2009, 8, 28. Analytica 2022, 3 460 12. Thakkar, R.; Thakkar, R.; Pillai, A.; Ashour, E.A.; Repka, M.A. Systematic screening of pharmaceutical polymers for hot melt extrusion processing: A comprehensive review. Int. J. Pharm. 2020, 576, 118989. [CrossRef] [PubMed] 13. Ti¸ ta, B.; Fulias, ¸ A.; Bandur, G.; Marian, E.; Ti¸ ta, D. Compatibility study between ketoprofen and pharmaceutical excipients used in solid dosage forms. J. Pharm. Biomed. Anal. 2011, 56, 221–227. [CrossRef] [PubMed] 14. Pereira, M.A.V.; Fonseca, G.D.; Silva-Júnior, A.A.; Fernandes-Pedrosa, M.F.; De, M.; Barbosa, E.G.; Gomes, A.P.B.; dos Santos, K.S.C.R. Compatibility study between chitosan and pharmaceutical excipients used in solid dosage forms. J. Therm. Anal. Calorim. 2014, 116, 1091–1100. [CrossRef] 15. De Barros Lima, Í.P.; Lima, N.G.P.B.; Barros, D.M.C.; Oliveira, T.S.; Mendonҫa, C.M.S.; Barbosa, E.G.; Raffin, F.N.; de Lima e Moura, T.F.A.; Gomes, A.P.B.; Ferrari, M.; et al. Compatibility study between hydroquinone and the excipi- ents used in semi-solid pharmaceutical forms by thermal and non-thermal techniques. J. Therm. Anal. Calorim. 2015, 120, 719–732. [CrossRef] 16. Matos, A.P.S.; Costa, J.S.; Boniatti, J.; Seiceira, R.C.; Pitaluga, A.; Oliveira, D.L.; Viçosa, A.L.; Holandino, C. Compatibility study between diazepam and tablet excipients: Infrared spectroscopy and thermal analysis in accelerated stability conditions. J. Therm. Anal. Calorim. 2017, 127, 1675–1682. [CrossRef] 17. Bezerra, G.S.N.; Colbert, D.M.; O’Donnell, C.; Cao, Z.; Geever, J.; Geever, L. Compatibility Study Between Fenbendazole and Poly(Ethylene Oxide) with Application in Solid Dispersion Formulations Using Hot-Melt Extrusion. J. Pharm. Innov. 2022, 1–13. [CrossRef] 18. Tita, I.C.; Lupa, L.; Tita, B.; Stan, R.L.; Vicas, L. Compatibility Studies of Valsartan with Different Pharmaceutical Excipients. Rev. Chim 2019, 70, 2590–2600. Available online: https://revistadechimie.ro/Articles.asp?ID=7386 (accessed on 1 September 2022). 19. Shakar AA, M.; Hossain, M.J.; Kayesh, R.; Rahman, A.; Sultan, M.Z. Incompatibility of Bisoprolol Fumarate with Some Super- disintegrating Agents. Br. J. Pharm. Res. 2015, 5, 137–145. [CrossRef] 20. Patel, P. Preformulation Studies: An Integral Part of Formulation Design. In Pharmaceutical Formulation Design—Recent Practices; IntechOpen: London, UK, 2020; pp. 1–19. 21. Melian, M.E.; Munguía, A.B.; Faccio, R.; Palma, S.; Domínguez, L. The Impact of Solid Dispersion on Formulation, Using Confocal Micro Raman Spectroscopy as Tool to Probe Distribution of Components. J. Pharm. Innov. 2018, 13, 58–68. [CrossRef] 22. Chadha, R.; Bhandari, S. Drug-excipient compatibility screening-Role of thermoanalytical and spectroscopic techniques. J. Pharm. Biomed. Anal. 2014, 87, 82–97. [CrossRef] 23. Ali, O.T.; Hassan, W.S.; Khayyat, A.N.; Almalki, A.J.; Sebaiy, M.M. HPLC Determination of Imidazoles with Variant Anti-Infective Activity in Their Dosage Forms and Human Plasma. Molecules 2020, 26, 129. [CrossRef] 24. Food and Agriculture Organization of the United Nations. Residues of Some Veterinary Drugs in Foods and Animals 1998. Avail- able online: http://www.fao.org/food/food-safety-quality/scientific-advice/jecfa/jecfa-vetdrugs/details/en/c/26/ (accessed on 1 August 2022). 25. Attia, A.K.; Saad, A.S.; Alaraki, M.S.; Elzanfaly, E.S. Study of thermal analysis behavior of fenbendazole and rafoxanide. Adv. Pharm. Bull. 2017, 7, 329–334. [CrossRef] [PubMed] 26. Rodrigues, L.N.C.; Tavares, A.C.M.; Ferreira, B.T.; Reis, A.K.C.A.; Katiki, L.M. Inclusion complexes and self-assembled cyclodex- trin aggregates for increasing the solubility of benzimidazoles. Braz. J. Pharm. Sci. 2019, 55. [CrossRef] 27. Kolašinac, N.; Kachrimanis, K.; Homšek, I.; Grujic, ´ B.; Uric, ´ Z.; Ibric, ´ S. Solubility enhancement of desloratadine by solid dispersion in poloxamers. Int. J. Pharm. 2012, 436, 161–170. [CrossRef] 28. Woodruff, M.A.; Hutmacher, D.W. The return of a forgotten polymer—Polycaprolactone in the 21st century. Prog. Polym. Sci. 2010, 35, 1217–1256. [CrossRef] 29. Yoganathan, R.; Mammucari, R.; Foster, N.R. Impregnation of Ibuprofen into Polycaprolactone using supercritical carbon dioxide. J. Phys. Conf. Ser. 2010, 2015, 1–5. [CrossRef] 30. Cipriano, T.F.; Da Silva, A.L.N.; Da Fonseca Thomé Da Silva, A.H.M.; De Sousa, A.M.F.; Da Silva, G.M.; Rocha, M.G. Thermal, rheological and morphological properties of poly(Lactic Acid) (PLA) and talc composites. Polimeros 2014, 24, 276–282. 31. Li, D.; Guo, G.; Fan, R.; Liang, J.; Deng, X.; Luo, F.; Qian, Z. PLA/F68/Dexamethasone implants prepared by hot-melt extrusion for controlled release of anti-inflammatory drug to implantable medical devices: I. Preparation, characterization and hydrolytic degradation study. Int. J. Pharm. 2013, 441, 365–372. [CrossRef] 32. Backes, E.H.; de Pires, L.N.; Costa, L.C.; Passador, F.R.; Pessan, L.A. Analysis of the degradation during melt processing of pla/biosilicate®composites. J. Compos. Sci. 2019, 3, 52. [CrossRef] 33. Bezerra, G.S.N.; de Lima, T.A.M.; Colbert, D.M.; Geever, J.; Geever, L. Formulation and Evaluation of Fenbendazole Extended- Release Extrudes Processed by Hot-Melt Extrusion. Polymers 2022, 14, 4188. [CrossRef] 34. Balu, R.; Sampath Kumar, T.S.; Ramalingam, M.; Ramakrishna, S. Electrospun polycaprolactone/Poly(1,4-butylene adipate-co- polycaprolactam) blends: Potential biodegradable scaffold for bone tissue regeneration. J. Biomater. Tissue Eng. 2011, 1, 30–39. [CrossRef] 35. Tanase-Opedal, M.; Espinosa, E.; Rodríguez, A.; Chinga-Carrasco, G. Lignin: A biopolymer from forestry biomass for biocompos- ites and 3D printing. Materials 2019, 12, 3006. [CrossRef] 36. Soto, C.; Otipka, R.; Contreras, D.; Yáñez, J.; Toral, M.I. Co-determination of two antiparasitics drugs by derivative spectropho- tometry and its photodegradation studies. J. Chil. Chem. Soc. 2013, 58, 1824–1829. [CrossRef] Analytica 2022, 3 461 37. Surov, A.O.; Vasilev, N.A.; Vener, M.V.; Parashchuk, O.D.; Churakov, A.V.; Magdysyuk, O.V.; Perlovich, G.L. Pharmaceutical Salts of Fenbendazole with Organic Counterions: Structural Analysis and Solubility Performance. Cryst. Growth Des. 2021, 21, 4516–4530. [CrossRef] 38. Esfahani, M.K.M.; Alavi, S.E.; Cabot, P.J.; Islam, N.; Izake, E.L. Pegylated mesoporous silica nanoparticles (Mcm-41): A promising carrier for the targeted delivery of fenbendazole into prostrate cancer cells. Pharmaceutics 2021, 13, 1605. [CrossRef] [PubMed] 39. Garala, K.; Joshi, P.; Patel, J.; Ramkishan, A.; Shah, M. Formulation and evaluation of periodontal in situ gel. Int. J. Pharm. Investig. 2013, 3, 29. [CrossRef] [PubMed] 40. Chakrapani, V.Y.; Gnanamani, A.; Giridev, V.R.; Madhusoothanan, M.; Sekaran, G. Electrospinning of Type I Collagen and PCL Nanofibers Using Acetic Acid. J. Appl. Polym. Sci. 2012, 125, 3221–3227. [CrossRef] 41. Chieng, B.W.; Ibrahim, N.A.; Yunus, W.M.Z.W.; Hussein, M.Z. Poly(lactic acid)/poly(ethylene glycol) polymer nanocomposites: Effects of graphene nanoplatelets. Polymers 2014, 6, 93–104. [CrossRef] 42. Panicker, C.Y.; Varghese, H.T.; Narayana, B.; Divya, K.; Sarojini, B.K.; War, J.A.; Alsenoy, C.V.; Fun, H.K. FT-IR, NBO, HOMO-LUMO, MEP analysis and molecular docking study of Methyl N-({[2-(2-methoxyacetamido)-4-(phenylsulfanyl)phenyl]amino}[(methoxycarbonyl) imino]methyl)carbamate. Spectrochim. Acta Part A Mol. Biomol. Spectrosc. 2015, 148, 29–42. [CrossRef] 43. Mohan, S.; Sundaraganesan, N.; Mink, J. FTIR and Raman studies on benzimidazole. Spectrochim. Acta Part A Mol. Spectrosc. 1991, 47, 1111–1115. [CrossRef] 44. Pezzoli, R.; Hopkins, M.; Direur, G.; Gately, N.; Lyons, J.G.; Higginbotham, C.L. Micro-injection moulding of poly(Vinylpyrrolidone- vinyl acetate) binary and ternary amorphous solid dispersions. Pharmaceutics 2019, 11, 240. [CrossRef] 45. Siahi, M.R.; Rahimi, S.; Monajjemzadeh, F. Analytical investigation of the possible chemical interaction of methyldopa with some reducing carbohydrates used as pharmaceutical excipients. Adv. Pharm. Bull. 2018, 8, 657–666. [CrossRef]

Journal

Analytica – Multidisciplinary Digital Publishing Institute

Published: Dec 12, 2022

Keywords: compatibility study; fenbendazole; polymeric excipients

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