Abstract

STUDY OF ENTERIC COATED SODIUM ALGINATE MICROSPHERE OF AZATHIOPRINE FOR COLON TARGETING

Abhishek S. B.*, Parthiban S., Senthil Kumar G. P. and Tamizh Mani T.

Abstract

The increase in incidence and prevalence of IBD over the last 15 years and its prevalence in most of the developing countries give the tremendous opportunity for the researchers to develop a colon-specific delivery of drugs for local and continuous effect. Microparticiulate drug delivery system have developed and tested for colon targeting. The aim of the study was to prepare site specific drug delivery of Azathioprine using sodium alginate, Eudragit S-100 and Ethyl cellulose as a pH sensitive polymer, respectively and to study the effect of coating of different polymers at different concentration. Core alginate microspheres of were prepared by ionotropic gelation method followed by cross linking with CaCl2, which was further coated with the pH dependent polymer Eudragit S-100 and Ethyl cellulose to prevent drug release in the upper gastrointestinal environment. Core and coated microspheres were characterized by FTIR spectroscopy, DSC, SEM, particle size analysis, drug content, entrapment efficiency, and In vitro drug release study in different simulated gastric fluids. SEM images revealed that the surface morphology was changed from rough surface to smooth surface after coating. FTIR study confirmed the compatibility of core and coated polymer with drug. The release of drug from core alginate microsphere release were pH independent and released 93.45%, 84.65% and 80.01% better controlled release at the end of 12 hrs for the formulationFA1, FA2, and FA3 respectively, followed Higuchi release kinetic model. Whereas the coated microsphere, the drug release was achieved only in pH 7.4 and avoiding release of drug in lower GIT pH environment. The Eudragit S100 coated formulation FB1 and FB2 release the drug after pH 7.4 whereas the Ethyl cellulose coated formulation FC1 and FC2 start to release the drug at pH 6.8. The release of coated formulation follows first order kinetics.

Keywords: Azathioprine, Sodium alginate, Ionic gelation , Ethyl cellulose, Eudragit S 100, Multiparticulate system.