Preparation of Biodegradable Microspheres Containing Repaglinide

The objective of the present study is to prepare and evaluate poly(ε-caprolactone) microspheres of repaglinide by using the solvent evaporation technique. The microspheres were prepared with different drug-to-carrier ratios: F1 (1:3), F2 (1:4), F3 (1:5), and F4 (1:6). The microspheres were then evaluated for particle size, SEM, FT-IR study, percentage yield, drug entrapment, stability studies, and for in vitro release kinetics. Scanning electron microscopy (SEM) revealed that microspheres were spherical with a nearly smooth surface morphology. The percentage yield and drug entrapment efÞ ciency were high for all the formulations. Fourier Transform-Infrared spectroscopy (FT-IR) showed that there was no chemical interaction between the drug and the polymer. No appreciable difference was observed in the stability study, in the extent of degradation of the product for 60 days in the microspheres that were stored at various temperatures. The in vitro release study showed that replaglinide release from all the formulations was slow and sustained over 12 h. Application of the in vitro drug release data to various kinetic equations indicated zero order release from repaglinide microspheres.