Multiparticulate Drug Delivery System for the Treatment of Diabetes Mellitus: In Vitro and In Vivo Evaluation

Biodegradable microspheres of poly(?)caprolactone were prepared by solvent evaporation method for controlled release of repaglinide. The prepared microspheres were spherical in shape having smooth surface. The average diameter was in the range of 24 to 31.04 µm. Drug entrapment efficiency of the prepared microspheres was in the range of 68.81% to 79.30%. Differential scanning calorimetry and x-ray diffraction analyses indicated the amorphous dispersion of drug in the microspheres. The drug release was continued up to 24 h depending upon the formulation variables; drug release was slow from the microspheres which were prepared with higher concentration of polymer and as the initial drug loading was increased, the drug release was also increased. A non-Fickian transport was the mechanism of drug release for all the microspheres. The in vivo anti-diabetic activity performed on steptozotocin induced rats indicated that the plain repaglinide has shown maximum percentage of reduction in blood glucose at the end of 3 h and then the percentage of reduction in blood glucose was decreased. While in case of rats treated with PCL5 microspheres, the percentage of reduction in glucose level was slow as compared to plain repaglinide within 3 h, but it was gradually increased to 74.86% at the end of 24 h.