Preparation and characterization of depot injectable microspheres of centchroman using ethyl cellulose

Abstract

Context: Centchroman (Ormeloxifene) is a nonsteroidal SERM; popularly used as a contraceptive; hence controlled delivery systems become a favorable choice for its administration. Objective: The present work aimed at preparing depot injectable microspheres of centchroman by using ethyl cellulose and evaluating it on various parameters. Materials and Methods: Depot injectables of centchroman were prepared by loading it in ethylcellulose (EC) microsphere (MS) and were evaluated for the influence of different pH of external phase, viscosity of internal phase, drug: EC ratio and EC: water soluble polymers associations on the physiochemical characteristics of the microspheres, percent loading; encapsulation, in vitro dissolution and biocompatibility tests. Results and Discussion: Compatibility studies suggested no significant interaction between the drug and polymers. Results indicated that in external phase of pH 7, centchroman showed lowest solubility and the microsphere resulted in maximum loading. Viscosities of internal phase had major effects on size, shape and drug loading. Association of two hydrophilic polymers with EC resulted in zero order release kinetics with r2>0.915 and the formulation protected the damage caused by drug to erythrocytes and 3T3 mouse embryonic fibroblasts upto10 mg/ml (with respect to drug). Conclusion: Biocompatible depot injectables were successfully fabricated to obtain a zero order release system.