Abstract
Frontiers in Life Science, 2015 Vol. 8, No. 3, 256–263, http://dx.doi.org/10.1080/21553769.2015.1063549 In vitro characteristics of an insulin suppository developed using palm oil base (HAMIN )and its hypoglycaemic effect on rabbits a∗ a b Sritharan Nair ,ZamriChik and Mohamed Ibrahim Noordin Department of Pharmacology, Faculty of Medicine, University of Malaya Bioequivalence and Testing Centre (UBAT), University of Malaya, 50603 Kuala Lumpur, Malaysia; Department of Pharmacy, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia (Received 15 October 2014; accepted 14 June 2015 ) The long-term administration of insulin requires the development of new delivery routes. Using a base developed in-house, called HAMIN , an insulin suppository containing 100 units (U) of insulin was formulated. The suppository was subjected to stability testing at various temperatures and the assay value was monitored. Other physical factors such as hardness, disintegration time, thermal analysis and dissolution were also tested. The suppository released more than 80% of its drug content in 30 min, and was stable for up to 11 months at − 20°C. The suppository effect was studied on 11 New Zealand white rabbits, with body weight ranging from 1.6 to 2.1 kg. The results show that there was a marked reduction in glucose content when the suppository was inserted. The average drop in glucose content was 2.7 mmol/L in 15 min from the time of insertion. The maximum drop in glucose content reached 3.9 mmol/L in 2 h. Plasma insulin level, quantified using an enzyme-linked immunosorbent assay, showed a value of more than 100 μIU insulin/ml blood after 30 min. Although the insulin bioavailability was expectedly low, the rate at which the hypoglycaemic effect took place and the percentage of glucose reduction were comparable to results after subcutaneous injection. Keywords: insulin suppositories; HPLC; animal study; ELISA 1. Introduction terms of hypoglycaemic effect but were unable to match Insulin resistance is a condition where the insulin produced the consistency and effectiveness of subcutaneous or intra- cannot exert the expected biological effect to attain suffi- venous injections. The closest alternative route, which led cient glycaemic control (Reavem 1995). The large increase to successful registration with the US Food and Drug in diabetic cases has led to a rise in studies on vari- Administration (FDA) but was followed by withdrawal by ous control measures. Different classes of drugs, such as the company, was Exubera, insulin delivered through an biguanides, sulfonylureas, alpha-glucoside inhibitors and inhaler into the lungs (Patel et al. 2005). Various other delivery modes of insulin using liposo- thiazolidinediones, each designed to treat diabetes from a mal formulations, iontophoresis and phonophoresis have different perspective, have been identified to control the been studied (Jani et al. 2012). These new technologies severity of the condition (Mohammed Salman & Naseerud- have been reported as being effective but too expensive din Inamdar 2012; Bhandari et al. 2013). However, no to be commercially viable. Acid degradation, pH sensitiv- treatments have been found that could replace insulin to ity, high variation in bioavailability and low bioavailability regulate the uptake of blood glucose into cells and muscle are some of the challenges posed by alternative delivery tissues. routes (Shivanand 2010). While acknowledging the need to Reduced endogenous insulin is commonly supple- present insulin medication in a more painless way, almost mented with isolated or recombinant insulin sources via all modes of delivery have so far fallen short of providing subcutaneous or intravenous injections (Al-Tabakha & an equivalent therapeutic dose. Arida 2008). Although these delivery routes provide the Studies on insulin delivered via the rectal route in best bioavailability, the need for continuous administra- humans found its bioavailability to be low (4–10%) com- tion of the hormone is a problem because of the pain and pared to subcutaneous injection (Owens 2002). Being a anxiety that attend the use of hypodermic needles. Vari- large molecule, the absorption of insulin through intracel- ous other delivery routes have been explored to replace or lular and cellular pathways is restricted. Various types of supplement subcutaneous insulin injection over the past 30 bases and additives such as phenols, sodium chloride and years (Wilson 2011). Many have shown positive results in *Corresponding author. Email: sritharannair@hotmail.com © 2015 Taylor & Francis Frontiers in Life Science 257 zinc ions have been studied with the objective of increasing lower strength suppository was prepared for the animal the bioavailability of insulin from suppositories (Brange & studies (12 U/suppository). Langkjaer 1992). The use of such chemicals increases the bioavailability, while causing a higher degradation rate of 2.2. High-performance liquid chromatography method insulin and some inconvenience to the users. However, any for insulin analysis active absorption from the rectal passage provides direct A high-performance liquid chromatography (HPLC) access into the systemic circulation, bypassing the hepatic method was developed for the detection and quantitation of circulation where the insulin will be extracted (Schade & insulin. A Waters Alliance 2695 Separation Module HPLC Valentine 2002). system equipped with a 2996 Photo Diode Array Detector Malaysian palm oil accounts for more than 24% of (owned by Pharmaniaga Research Centre, Malaysia) was the global trade in oil and fat. The thermostability and used. The column used was a Waters Insulin-HMWP, with lack of polymorphism shown by palm oil give it advan- dimensions of 7.8 × 300 mm, a pore size 125 Å and a 2 tages over the traditionally used theobroma oil in the μm ethylene bridged hybrid silica stationary phase (Koza production of suppository bases. The authors have engaged et al. 2012). The mobile phase is an acidic degassed pre- in studies on a newly developed palm oil base, called , to investigate the possibility of using it as an mix of glacial acetic acid (15%), acetonitrile (20%) and HAMIN insulin suppository base and to gauge the hypoglycaemic 0.1% arginine solution (65%) run at a flow rate of 0.4 effect in experimental animals given high doses of insulin. ml/min. Ultraviolet detection at 276 nm was performed. The palm kernel oil suppository base was prepared using Insulin from bovine pancreas and human recombinant pan- HAMIN, which is a mixture of hydrogenated palm ker- creas (Sigma) was used as reference material. The injection nel oil and hydrogenated palm kernel stearin (Noordin & volume was set to 100 μl. The temperature of the HPLC Chung 2007). Drugs such as paracetamol and aspirin have system was maintained at 25°C. The insulin reference stan- dard was diluted in 0.01 N HCl to obtain a concentration of shown positive results using this base as a suppository 5 U/ml. The sample was melted in a volumetric flask con- (Noordin & Chung 2004). The base has undergone allergy taining 0.01 N HCl, in a water bath to provide sufficient testing in an Organisation for Economic Co-operation and dissolution for the suppository to release the hormones in Development (OECD)-accredited laboratory in the UK and solution, to produce similar concentrations. been found safe for use in in vivo studies (Halal Focus). 2.3. Uniformity of dosage 2. Method The uniformity of dosage test was performed on 10 sup- 2.1. Preparation of suppositories positories individually by dissolving each suppository in a A fat base was chosen to develop the insulin suppository, separate volumetric flask containing 0.01 N HCl in a water as a fat-based suppository gives a general melting range bath. The water bath was maintained at 50°C for rapid of 30–40°C, readily melts on warming and rapidly hard- dissolution of the suppositories. The volumetric flask con- ens on cooling, is miscible with other ingredients and is taining the suppository in 0.01 N HCl was stirred until the non-irritating. The base was melted in a glass beaker at suppository visually dissolved. The solution was immedi- a slow rate on a laboratory-scale hotplate using a water ately taken out to avoid any degradation of the insulin, bath and a magnetic stirrer. Human recombinant insulin cooled, filtered using a 0.45 μm filter and chromatographed (Sigma-Aldrich, WGK, Germany) was incorporated into using HPLC. the base. The temperature of the hotplate and the water bath was set to 40°C and was monitored carefully to avoid 2.4. Dissolution method heat degradation of the hormone. The recombinant human insulin consists of two polypeptide chains linked by disul- A dissolution test was performed to measure the release of fide bonds, similar to the native hormone produced by insulin from the suppositories over time. As the supposito- the beta-cells in the human pancreas (Sigma-Aldrich). The ries were light, sinkers were used to immerse them in 500 base was pipetted into the plastic moulds. Each suppository ml of medium (0.01 N HCl) at 37°C. The paddle speed was was designed to contain approximately 100 units (U) of set to 100 rpm. Dissolution samples were withdrawn at 15, insulin. The suppository was cooled at 25°C for 48 h before 30, 60, 120, 180, 240 and 300 min. being stored in a freezer at a temperature below − 20°C. Placebo suppositories were developed in similar manner 2.5. Thermal analysis without the incorporation of insulin. The suppositories were packed in a 1.5 ml disposable plastic suppository Thermal analysis was carried out on human recombinant mould. They were incubated at 8°C and 30°C, and tested insulin, pure HAMIN and insulin suppositories. A Mettler at 0 and 1 month. Estimated shelf-life was calculated using Toledo differential scanning calorimeter (DSC) was used. the Arrhenius equation and the 1 month stability data. A Nitrogen gas at a flow rate of 50 ml/min was used. Three 258 S. Nair et al. test samples of pure insulin, pure HAMIN and insulin sup- stopping reagent and briefly mixing the contents by gently positories were weighed and loaded into the perforated pan shaking the plate. of the DSC. The pan was closed with a cover and crimped. A microplate optical density reader was used to mea- The sample was then placed in the DSC heating chamber. sure the absorbance of the samples at 450 nm and 490 nm. The programme was set to heat the bovine insulin from Measurements were taken within 60 min from the time the − 20°C to 320°C at a rate of 20 K/min. The DSC had been stop solution was added. calibrated before the study, using indium and zinc. 3. Results 2.6. Animal studies procedure 3.1. Physical attributes All experiments were performed in accordance with the The hardness of the suppositories was tested using an auto- relevant regulations and approved guidelines. The animal mated hardness tester, and the average value obtained was research protocol [FARMAKO/28/08/2013/SN(R)] was 2.1 kP. The disintegration of the suppositories was tested approved by the University of Malaya Institutional Ani- in water at 37°C, using discs. The suppositories dissolved mal Care and Use Committee (IACUC) to study the effect within 13 min. of an insulin suppository in an animal model. The suppos- itory effect was studied on 11 New Zealand white rabbits, 3.2. Validation of high-performance liquid with body weight ranging from 1.6 to 2.1 kg, obtained from chromatography method East Asia Rabbit Corporation (Malaysia). After a 2 week acclimatization period, eight rabbits were given an insulin The assay method using HPLC was validated from 0.02 suppository (12 U/suppository) and three rabbits a placebo mg/ml to 0.5 mg/ml. The insulin peak eluted at about 22 suppository. All the rabbits were well fed and none of min (Figure 1). Five concentrations of insulin were stud- them was starved. A suitable restraining box was used to ied for the standard and the placebo spiked with reference hold the rabbit firmly. The hair on the ears was shaved to standard. The y -intercept from the plotted graph was 1.3% improve the visibility of the veins. A diluted alcohol swab for standard and 0.5% for sample (spiked placebo) prepa- was used to disinfect the area and a blood sample was ration. The coefficient of determination was about 1.00. withdrawn using a butterfly needle. The blood was sam- The precision and accuracy were obtained using three pled at 0 (pre-dose), 30, 60 and 120 min. About 1–2 ml replicate samples at three concentrations ranging from of blood was collected from the marginal ear veins into a 0.02 mg/ml to 0.5 mg/ml. The relative standard deviation plain tube. The blood was centrifuged at 3500 rpm and the (RSD) was 1.9% and the percentage accuracy was about plasma was separated into two portions, one for the deter- 100.5 ± 1.3% at a 95% confidence level. mination of glucose and the other for the determination of insulin by enzyme-linked immunosorbent assay (ELISA). 3.3. High-performance liquid chromatography assay The sample for glucose testing was sent to an independent results laboratory (Gribbles Pathology, Malaysia). HPLC was used to measure insulin concentrations in sam- ples obtained from stability studies. The International Con- 2.7. Insulin quantitative analysis by enzyme-linked ference on Harmonisation of Technical Requirements for immunosorbent assay method Registration of Pharmaceuticals for Human Use (ICH) The insulin was quantitated using an insulin immunoas- guideline on stability studies for products intended to be say kit (IBL International, Hamburg, Germany). The kit refrigerated recommends accelerated storage conditions of contained a microtitre plate layered with a monoclonal 25 ± 2°C/65% relative humidity (RH) and long-term stor- antibody. First, 50 μl of each concentration of insulin stan- age at 5 ± 3°C. However, in this study the accelerated dard solution or the sample solution ranging from 0–500 condition was set to 30°C/75% RH. The assay results μIU/ml was pipetted into the wells of a microplate. Then, obtained at 1 month were about 3.21 mg and 3.00 mg at 50 μl of anti-insulin horseradish peroxidase conjugate was pipetted into the same well. The microplate was incubated for 30 min at room temperature on a horizontal shaker. After decanting the supernatant, each well was washed three times with 0.4 ml of washing solution. The washing solution was carefully removed by inverting the plate and tapping it firmly on clean blotting paper. Then, 200 μlof freshly prepared substrate solution was pipetted into each well within 15 min. The plate was then incubated for 15 min at room temperature on a shaker, avoiding direct sun- Figure 1. Chromatogram of insulin reference standard. light. Finally, the reaction was stopped by adding 50 μlof Frontiers in Life Science 259 Table 1. Assay results for insulin suppositories incubated all 10 suppositories tested was 5.8%. The dissolution pro- under refrigerated and stressed conditions. cedure of the suppositories was initially developed in a basket at various speeds. In the basket, the suppositories Incubation condition Initial After 1 month % Reduction melted into droplets but stayed within the mesh of the bas- Refrigerated ket. The base adhesion to the mesh was greater than its (5 ± 3 °C) 3.33 mg 3.21 mg 3.6% solubility in water. The suppositories melted slowly up Stressed to 5 h at 100 rpm but only managed to release 14% of (30 ± 2°C/75% RH) 3.33 mg 3.00 mg 9.9% insulin in the medium when using the basket. It appeared that the medium was not able to penetrate the molten base and dissolve the hormone completely. Polysorbate, a non- ionic surfactant, was used in the dissolution medium to increase the release of insulin from the melted droplets. This increased the dissolved insulin percentage to 80% 40 using a paddle and sinker. The sample was filtered using a 0.45 μm nylon filter and chromatographed using similar HPLC conditions to those described above. Figure 2 shows the dissolution profile of the insulin suppository. 0 50 100 150 200 250 300 350 Time (Minutes) 3.5. Thermal analysis Figure 2. Dissolution profile of insulin suppository. 3.5.1. Thermal characteristics of HAMIN Figure 3 shows the DSC curve for HAMIN when heated temperatures of 5°C and 30°C, respectively, compared to from − 20°C to 200°C and cooled back to − 20°C at a rate the initial assay value of 3.33 mg (Table 1). Using the of 20 K/min. Melted HAMIN was cooled to − 20°C and Arrhenius equation, the calculated shelf-life at − 20°C was remelted to 200°C. The purposes of the heating and cool- about 14 months. Practically, the assay at 11 months was ing processes are to reveal the crystallization properties of about 91.4% for samples stored below − 20°C. HAMIN and to identify the presence of polymorphism of HAMIN. The curve shows a melting peak at 32.90°C and H of − 144.04 J/g. HAMIN showed two polymorphic 3.4. Uniformity of dosage and dissolution results forms in the first heating and only a single form when The uniformity of dosage test showed that the amount of remelted using DSC. There was no significant difference insulin was consistent and homogeneously distributed in between the melting points of the first and the second melts all suppositories tested. The percentage RSD obtained from (p > 0.05). Figure 3. Thermal characteristics of HAMIN base. % of Dissolution 260 S. Nair et al. Figure 4. Thermal characteristics of insulin. After the remelting of HAMIN, the peak reached its 3.6. In vivo studies in rabbits highest point at 34.13°C. This melting peak shows that the 3.6.1. Glucose assay base remains solid at room temperature and will melt at The plasma glucose content was analysed using the Sys- body temperature. mex Automated Chemistry Analyzer. It was found that the average plasma glucose level dropped from 5.8 mmol/l to 3.1 mmol/l in the first 15 min. It further dropped to 2.5, 3.5.2. Thermal characteristics of human recombinant 2.2 and 1.9 mmol/l in samples withdrawn at 30 min, 1 h insulin and 2 h, respectively, in rabbits given an insulin supposi- Figure 4 describes the thermal characteristics of human tory. There was no significant drop in plasma glucose level recombinant insulin when heated using the DSC from in rabbits given a placebo suppository. The glucose level − 20°C to 320°C at a rate of 20 K/min. The thermal ranged from 5.2 to 5.6 mmol/l for the same sampling time analysis of insulin showed a single degradation peak at interval. 74.24°C and H of − 266.12 J/g. 3.5.3. Thermal characteristics of HAMIN insulin 3.6.2. Insulin assay suppository Using the standard solutions provided in the insulin Figure 5 describes the thermal characteristics of HAMIN immunoassay kit, a calibration curve was plotted using insulin suppository when heated using the DSC from a five concentration of insulin ranging from 6.25 to 100 ) value for temperature of − 20°C to 320°C at a rate of 20 K/min. μIU/ml. The coefficient of determination (R The thermal behaviour of the insulin was portrayed by the curve was above 0.98. In rabbits given an insulin sup- two distinct peaks. The peak seen at 33.44°C shows the pository, the insulin content in the plasma increased from melting point of HAMIN when incorporated with insulin. 6.08 to 7.60 μIU/ml in 15 min. It shot up to more than The degradation peak of insulin in the suppository has also 100 μIU/ml within the next 15 min, and the value stayed shifted to 98.73°C compared to 74.24°C. Thus, the insulin the same in the 1 h interval sample. At 2 h, the amount melting peak increased when incorporated with HAMIN. of plasma insulin had reduced to 77.01 μIU/ml. The cal- This result shows that insulin combined with HAMIN was culated area under the curve (AUC) and the maximum more resistant to heat than insulin alone. concentration (C ) observed after the administration max Frontiers in Life Science 261 Figure 5. Thermal analysis of the HAMIN insulin suppository. of insulin suppositories were 9219.8 and 100 μIU/ml, The stability data show that the formulation has to be respectively. stored well below 8°C to reduce the drop in assay content The insulin concentrations measured in all rabbits of insulin. Further studies were conducted on this prepara- treated with placebo ranged from 5.3 to 6.9 μIU/ml at all tion to measure the insulin bioavailability in plasma and to intervals tested. The calculated AUC and observed C assess the ability of this preparation to deliver a therapeutic max were 757.5 and 6.9 μIU/ml, respectively. concentration of insulin in vivo. Since none of the rabbits developed diabetes with streptozotocin administered in the range of 65–100 mg/kg body weight, the insulin content of each suppository was 4. Discussion increased to 12 U to see a marked glucose-lowering effect. In this study, a new formulation insulin suppository has A further increase in streptozotocin to 130 mg/kg body been developed and fully tested for its physical and thermal weight resulted in mortality. characteristics, and also tested in in vivo studies in rab- The glucose reduction was an almost instantaneous bits. The HAMIN insulin suppository passed all the tests response, as trace amounts of insulin started to trigger the for its suitability as a suppository preparation of insulin. absorption of glucose. An amount of 1.5 μIU/ml reduced The results showed that insulin suppositories developed about 48.6 mg/dl ( − 47%) of glucose in just 15 min. How- using HAMIN base have potential formulation stability at ever, as the insulin content kept on increasing, the plasma − 20°C. Characterization of the thermal properties using glucose level did not show corresponding reductions in the DSC showed that insulin interacts with HAMIN when both following intervals. This indicates that increasing insulin of them are incorporated together as a suppository. This levels in the blood circulation could not effect a propor- interaction give desirable properties to insulin, such as tional uptake of glucose by cells and tissues. It appears enhanced heat stability. that there is a limiting factor to a continuous uptake of The dissolution data show that the suppository dis- glucose into cells or a mechanism to maintain a mini- solved and released 80% of its content within 15 min mal blood glucose level, even when a high concentration at 37°C. The in vivo study conducted in rabbits shows of insulin is found in the bloodstream. It was noted that that the suppositories melted rapidly in the temperature one of the eight rabbits given an insulin suppository had range of 38.5–39.6°C in the rabbit’s rectal cavity (Merck seizures and became unconscious owing to the severe and Manuals). rapid reduction in the glucose level. The total amount 262 S. Nair et al. of glucose uptake caused by the insulin suppository was 5. Conclusion 702.6 mg in 2 h. This study shows that the palm oil base HAMIN has good Yoshimitsu et al. (1981) reported that the plasma characteristics and is suitable for use as an insulin sup- insulin availability at 30 min was 30 ± 5.6 μU/ml, when pository to deliver the required therapeutic dose through 0.7–0.9 U/kg of insulin was administered in humans. This the human intestinal membrane. The insulin suppository is equivalent to a glucose drop of 10 mg/dl in 45 min has all the desirable features for use as an alternative to (Yoshimitsu et al. 1981). In the present study, the glucose subcutaneous insulin injection, especially in patients with reduction at 30 min was about 59.4 mg/dl. a needle phobia. Although the high-dose insulin suppos- In a study on humans administered subcutaneously itory did not increase plasma insulin content, the rate at with regular human insulin of 0.15 U/kg, maximum which the hypoglycaemic effect occurred and the percent- concentrations of insulin reached 36 μIU/ml (GLOBAL- age of glucose reduction were comparable to those seen RPh). Using 12 U insulin per suppository, the maximum after subcutaneous injection. The results of this study could concentration of insulin observed was greater than 100 be used in the development of insulin suppositories, which μIU/ml. However, the time taken to reach the maximum may improve compliance in diabetic patients administer- concentration of insulin for the subcutaneous injection and ing subcutaneous insulin injections. Indirectly, this method the suppository was 40–50 min and 30 min, respectively will also increase the demand for and use of palm oil in the (Sanlioglu et al. 2013). This shows that the suppository was pharmaceutical industry.2 able to match the rapid-acting analogues of insulin in term of response, but required a much higher dose to cause the same effect owing to poor bioavailability. Disclosure statement Given the size of insulin, at concentrations of 100 U No potential conflict of interest was reported by the authors. and the rectal pH of 7.9, the hormone mostly exists in hexamer form (Brange et al. 1990). It dissociates and is absorbed into the capillaries in its dimeric or monomeric Funding form. The absorption of the poorly solubilized insulin at This project was funded by the University Malaya Post Graduate rectal pH is achieved through the transcellular and para- Research Fund [grant nos PV114/2011A and RG131/09HTM]. cellular routes (Muranishi et al. 1993). In the transcellu- lar route, the lipophilicity of the suppository formulation plays an essential role, whereas a simple drug diffusion process enables the drug to be absorbed through the para- References cellular route. However, the diffusion rate of the insulin Al-Tabakha MM, Arida AI. 2008. Recent challenges in insulin will be slow owing to the low coefficient partition of the delivery systems: a review. Indian J Pharm Sci. 70: 278–286. molecule (Shi et al. 2006). Insulin absorption from the Bendayan M, Ziv E, Gingras D, Ben-Sasson R, Bar-On H, colon and the duodenal wall was studied by Bendayan Kidron M. 1994. Biochemical and morpho-cytochemical et al. (1994). The study found that biologically active evidence for the intestinal absorption of insulin in con- insulin is absorbed by the intestinal mucosa and transferred trol and diabetic rats. Comparison between the effective- to the blood circulation. Multiple routes of transfer, such ness of duodenal and colon mucosa. Diabetologia. 37: 119–26. as through the endosomal compartment, Golgi apparatus, Bhandari U, Chaudhari HS, Khanna G, Najmi AK. 2013. Antidi- membrane interdigitations, interstitial space and endothe- abetic effects of Embelia ribes in high fat diet and low dose lial plasmalemmal vesicles, were identified (Bendayan streptozotocin induced type 2 diabetic rats. Front Life Sci. et al. 1994). 7:186–196. The absence of a similar glucose reduction pattern Brange J, Langkjaer L. 1992. Chemical stability of insulin, influ- ence of excipients, formulation, and pH. Acta Pharm Nord. in rabbits given a placebo suppository confirms that the 4:149–158. insulin source is the suppository and not the endogenous Brange J, Owens DR, Kang S, Volund A. 1990. Monomeric insulin. The total plasma glucose content was reduced by insulin and their experimental and clinical implications. more than 50% in 2 h using the 100 U insulin suppos- Diabetes Care. 13:923–954. itory compared to the AUC in rabbits given a placebo GLOBALRPh. Home page. Available from: http://www.global rph.com/rapid-acting-analogues.htm suppository. Halal Focus. Home page. Available from: http://halalfocus.net/ Many studies have used various types of surfactants malaysia-palm-oil-base-for-pharmaceutical-cosmetic- and absorption enhancers to increase the bioavailability of products insulin from suppositories. Some claim to have produced Hosny EA, Al-Marzouki ZM, Metwally ME, Souaida MY, a comparable hypoglycaemic effect to subcutaneous injec- Alshaik AR. 2003. Evaluation of efficiency of insulin suppository formulations containing sodium salicylate or tion at short time intervals, but over a longer duration they sodium cholate in insulin dependent diabetic patients. Boll were unable to match either the hypoglycaemic effect or Chim Farm. 142:361–6. the insulin bioavailability of the subcutaneous injection Jani P, Manseta P, Patel S. 2012. Pharmaceutical approaches (Hosny et al. 2003). related to systemic delivery of protein and peptide drugs: Frontiers in Life Science 263 an overview. Int J Pharm Sci Rev Res. 12 Article-007: Patel A A, Coleman CI., White CM. 2005. Focus on: Exu- 42–52. bera an orally inhaled insulin. Formulary. Available from: Koza S, Hong P, Fontain KJ. 2012. Size exclusion ultra http://goo.gl/6CKxyb performance liquid chromatography for the analysis of Reavem GM. 1995. Pathophysiology of insulin resistance in covalent high molecular weight insulin. Available from: human disease. Physiol Rev. 75:473–486. http://goo.gl/EGT4v3 Sanlioglu A D., Altunbas H A, Balci MK, Griffith TS, Sanlioglu Merck Manuals. Home page. Available from: http://www.merck S. 2013. Clinical utility of insulin and insulin analogs. Islets. manuals.com/vet/appendixes/reference_guides/normal_ 5:67–78. rectal_temperature_ranges.html Schade DS, Valentine V. 2002. To pump or not to pump. Mohammed Salman I, Naseeruddin Inamdar Md. 2012. Effect Diabetes Care. 25:2100–2102. of gliclazide on cardiovascular risk factors involved in split- Shi K, Cui F, Yu Y, Zhang L, Tao A, Cun D. 2006. Prepara- dose streptozotocin induced neonatal rat model: a chronic tion and characterization of a novel insulin–phospholipid study. Int J Basic Clin Pharmacol. 1:196–201. complex. Asian J Pharm Sci. 1:168–174. Muranishi S, Yamamoto A. Okada H. 1993. Rectal and vaginal Shivanand P. 2010. Non-invasive insulin delivery systems: chal- absorption of peptides and proteins. In: Biological Barriers lenges and needs for improvement. Int J PharmTech Res. to Protein Delivery. Pharmaceutical Biotechnology. 4: 199– 2:603–614. 222. Sigma-Aldrich. Home page. Available from: http://www.sigma aldrich.com/catalog/product/sigma/91077c?lang = en& Noordin MI, Chung LY. 2004. A rapid micro quantification method of paracetamol in suppositories using differential region = MY scanning calorimetry. Drug Dev Ind Pharm. 30:925–930. Wilson EJ. 2011. Three generations: the past, present, and Noordin MI, Chung LY. 2007. Palm kernel oil blends as sup- future of transdermal drug delivery systems. Available from: pository bases in the delivery of aspirin. Journal of the http://goo.gl/AfCYwd. University of Malaya Medical Centre (JUMMEC). 10: Yamasaki Y, Shichiri M, Kawamori R, Kikuchi M, Yagi T, Arai 43–50. S, Tohdo R, Hakui N, Oji N, Abe H. 1981. The effectiveness Owens D R. 2002. New horizons – alternative routes for insulin of rectal administration of insulin suppository on normal and therapy. Nat Rev Drug Discov. 1:529–540. diabetic subjects. Diabetes Care. 4:454–458.
Journal
Frontiers in Life Science
– Taylor & Francis
Published: Jul 3, 2015
Keywords: insulin suppositories; HPLC; animal study; ELISA
