FORMULATION OF SPRAY DRIED MUCOADHESIVE MICROSPHERES OF REPAGLINIDE: IN VITRO AND IN VIVO EVALUATION
Repaglinide, an oral hypogl ycemic agent is having drawbacks of low systemic bioavailability, poor absorption in upper intestinal tract, and short biological half-life (1-2h). A sustained release system designed to increase its residence time in the stomach with contact with the mucosa was achieved through the preparation of mucoadhesive microspheres by spray drying technique consisting of different t ype of mucoadhesive polymers like HPMC, HPC, Carbopol 934 P, Sodium CMC, chitosan, PVP, Sodium alginate and ethyl cellulose with repaglinide, an oral hypogl ycemic agent. The particle size was determined by stage and eye-piece micrometer. The surface morphology and particle shape were studied by SEM. The microspheres were evaluated for their micro encapsulation efficiency, in vitro wash off mucoadhesion test in vitro drug release and in vivo study. Mucoadhesive microspheres prepared were spherical in shape, size range of 2.5-5µm.The micro encapsulation efficiency was in the range of 75.75 % - 88.36 % and microspheres of F 1, F 2, F 3 , F 4, F 6, F 7 have shown good mucoadhesive property. Release kinetic studies indicated that all formulations followed first order release pattern and r elease is dependent of amount of drug to be released. Formulations F 2 , F 5, F 6, F 7 followed the diffusion mechanism and F 3, F 4 followed non fickian drug release. F 1 followed anomalous transport mechanism for drug release. The drug release was slow and prolonged for 8hrs. In vivo studies in normal healthy rabbits were performed with mucoadhesive of formulation F 3 and repaglinide. F 3 had shown significant hypogl ycaemic effect upto period from 6 hrs to 20 hrs, whereas repaglinide showed the reduction of 38.91% after a period of 3hrs and reached normal within 6 hrs