Formulation and Characterization of Sustained-Release Microspheres of Oxazepam

The aim of this study was to formulate and characterize oxazepam-loaded microspheres for sustained drug release to enhance its therapeutic efficacy in the treatment of anxiety and insomnia. Various formulations of microspheres were prepared using HPMC, ethyl cellulose (EC), and guar gum as polymers, and their physical properties, such as yield, drug entrapment efficiency, buoyancy, and floating lag time, were evaluated. The optimized formulation (F4) exhibited a high percentage yield (73.32±0.22%) and drug entrapment efficiency (72.23±0.32%). Furthermore, F4 showed the shortest floating lag time (55±3 sec.) and the highest percentage buoyancy (76±2%), indicating its ability to remain buoyant in the gastric medium for prolonged periods. In-vitro drug release studies demonstrated that formulation F4 provided a sustained release of oxazepam over 12 hours, with 98.78% drug release, significantly improving upon the rapid release observed with marketed formulations. The release kinetics followed a zero-order release model (R² = 0.9748), ensuring a constant drug release rate. These results suggest that oxazepam-loaded microspheres could serve as an effective sustained-release formulation for long-term management of anxiety disorders, reducing dosing frequency and improving patient compliance.