Prepare and Optimization of Cyclobenzaprine Hydrochloride Sustained Release Microspheres

Abstract

Cyclobenzaprine, a centrally acting skeletal muscle relaxant used for acute musculoskeletal conditions, suffers from a short half-life and systemic side effects that limit its clinical efficacy, necessitating the development of sustained release formulations. This study aimed to formulate and evaluate Cyclobenzaprine microspheres using ethyl cellulose as the polymeric matrix to achieve controlled drug delivery. Microspheres were prepared through a standardized method, and preformulation studies were conducted on the pure drug to establish its physicochemical characteristics. The prepared formulations (F1, F2, and F3) were evaluated for entrapment efficiency, drug loading, percentage yield, and in vitro drug release profiles. The entrapment efficiency ranged from 34.75% to 87.45%, with drug loading values between 18.10% and 22.65%, and percentage yield varying from 44.8% to 63.2%. In vitro dissolution studies demonstrated controlled release behavior, with F1, F2, and F3 releasing 80.5%, 77.8%, and 72.9% of the drug, respectively, over 8 hours. Among the three formulations, F3 exhibited the most consistent and reliable performance with the highest entrapment efficiency (87.45%), optimal drug loading (22.65%), and the slowest drug release profile (72.9% at 8 hours), indicating superior sustained-release characteristics. These findings suggest that the F3 formulation is promising for further investigation and warrants stability studies, preclinical, and clinical evaluations to confirm its potential as an improved therapeutic option for musculoskeletal disorders.