Abstract:
Oral insulin delivery remains a mirage among the pharmaceutical scientists due to inability to circumvent its inherent stability in gastrointestinal tract after oral administration. In this study, insulin-loaded microparticles for oral delivery were prepared with snail epiphragm and chitosan combined at different concentrations of chitosan using a novel method based on polymer hybridization. Four insulin-loaded batches were prepared and labeled as FS1, FS2, FS3 and FS4 containing 1:1, 1:2, 1:3 and 1:4 of snail epiphragm (SE) and chitosan (CS), respectively. The unloaded (drug free) batch was similarly prepared and labeled as FS0. Characterizations such as particle size, morphology and thermal properties were evaluated. The in vitro release and blood glucose reduction after oral administration to diabetic rats was determined. The particles formed ranged from 121.0 ± 0.12 to 59± 1.06 μm, and were generally not spherical and varied in sizes. The loading and encapsulation efficiency were generally high. The minimum and maximum EE were 90.5 ± 0.03 and 97.7 ± 0.22 % for FS2 and FS4, respectively. The in vitro release of insulin from the formulations varied with the chitosan concentration, with FS1 (50 %) and FS2 (89 %). The percentage blood glucose reduction for the subcutaneously administered insulin was significantly (p < 0.001) higher than the formulations. In vivo studies revealed a pronounced hypoglycaemic (34.67±3.65 %) effect in diabetic rats after peroral administration of the insulin-loaded MPs compared to the free oral insulin solution within 12h of administration. Therefore, these findings clearly suggest that the snail epiphragm-chitosan based microparticles offer an interesting mode of insulin delivery orally for the treatment of diabetes.
