FORMULATION AND EVALUATION OF CHLORZOXAZONE MICROSPHERES

Aiswarya A.* and Dr. Suja C.

ABSTRACT

Microspheres are characteristically free flowing powders having particle size ranging from 1-1000μm consisting of proteins or synthetic polymers. Chlorzoxazone is a centrally acting muscle relaxant used to treat muscle spasm and the resulting pain a discomfort. It is a BCS class II drug having a shorter half-life (1.1 hour) with the dose administration of 3-4 times a day leads to decrease patient compliance. The present study is aimed to improve the patient compliance, reduce adverse effect, protect the drug from enzymatic degradation, to increase the solubility by preparing sustained release microsphere using different polymers like HPMC and carbopol by varying concentration using ionotropic gelation method. Optimization study have been done by Design Expert Software using central composite design and 13 formulations were prepared. All the formulations were evaluated for micrometric properties, percentage yield, mean particle size, drug content, entrapment efficiency, SEM studies and in vitro drug release. Depending upon the concentration, the percentage yield is found between 62.5% to 86.33% in all formulations. The mean particle size of microspheres significantly increases with increasing polymer concentration and the range between 141.2μm to 198.6μm. Among all the formulations, F8 showed high drug content (97.3%) and entrapment efficiency 68.56. The surface morphology of microspheres was characterized by SEM and it was discrete and spherical in shape .The in vitro drug release studies revealed that F8 formulation exhibits maximum drug release and hence was selected as the optimized formulation .The mechanism of drug release was found to be first order kinetics and kosmeyer – peppas model with fickian diffusion mechanism. From the stability studies microspheres showed no significant change in the physical appearance and drug content.

Keywords: Chlorzoxazone, Microspheres, Muscle relaxant, HPMC, Carbopol, Optimization.