Abstract

PREPARATION AND EVALUATION OF PREGELATINIZED STARCH MICROSPHERES FOR CONTROLLED RELEASE OF LORNOXICAM

K. P. R. Chowdary*, K. Ravi Shankar and S. V. V. Subrahmanyam

Abstract

Microspheres are a novel type of controlled/sustained release drug delivery systems to achieve prolonged therapeutic effect by continuously releasing medication over an extended period of time after administration. Though several polymeric materials are available for microspheres, there is a continued need for development of new, efficient and cost effective polymers for the preparation of controlled release microspheres. Pregelatinized starch, a partially hydrolyzed starch, is a biodegradable, water dispersible and swell able polymer. The objective of the present study is to develop and evaluate pregelatinized starch microspheres of lornoxicam for control release application. Microspheres with starch or pregelatinized starch alone could not be prepared by conventional microencapsulation methods as they are insoluble in most of the solvents including water. Pre gelatinized starch-alginate microspheres containing lornoxicam could be prepared by ionic-gelation method using an orifice. The microspheres prepared are discrete, spherical, free flowing and are of uniform size (1435μm). Microencapsulation efficiency was in the range 73.6-86.7 %. Lornoxicam release from all the microspheres prepared was slow and spread over 8-12 h and the release was dependent on the composition of the microspheres. Drug release from the microspheres prepared was diffusion controlled and followed first order kinetics. A good linear relationship was observed between percent coat and drug release rate (K1) of the microspheres the relationship could be expressed by the linear equation, Y= -0.007X+0.807 (R2=0.987), where Y is release rate (K1) and X is percent coat in the microspheres. Pre gelatinized starch-alginate microspheres were found suitable for controlled release application.

Keywords: Microspheres, Lornoxicam, Pregelatinized starch, Orifice method, Controlled release.