Development and Evaluation of PEG-gelatin-based Microparticles to Enhance the Oral Delivery of Insulin

Abstract

Background: Diabetes mellitus is a global disease identified by hyperglycemia due to defects in insulinsecretion, insulin action, or both.Objective: The main objective of this research was to evaluate the ability of gelatinized Poly(ethylene glycol)(PEG) microparticles to be used as carriers for oral insulin delivery via double emulsion preparation.Methods: Five different batches of the formulation consisting of gelatin:PEG were prepared as follows: 0:1(W1), 1:0 (W2), 1:1 (W3), 1:3 (W4), and 3:1 (W5). The prepared microparticles (from insulin-loaded batches)had particle sizes ranging from 19.5 ± 0.32-23.9 ± 0.22 μm and encapsulation and loading capacities rangingfrom 78.8 ± 0.24-88.9 ± 0.95 and 22.2 ± 0.96-29.7 ± 0.86%, respectively. The minimum and maximum invitro release rates were 8.0 and 66.0%, respectively, for batches W1 and W2 at 8 h.Results: Insulin-loaded MPs induced a significant decrease in glucose levels, with a reduction from 100 to33.35% in batch W5 at 9 h compared to that of subcutaneous insulin (100 to 22.63%). A liver function studyshowed that the formulation caused no obvious toxicity to the experimental rats.Conclusion: Gelatinized PEG-based microparticles as insulin delivery systems may open a new window intothe development of oral insulin for diabetic treatment.