Gastroretentive Floating Microspheres of Metaxalone: A Novel Drug Delivery Approach for Muscle Relaxation

Floating microspheres are advanced gastroretentive drug delivery systems that have the ability to extend gastric residence time and increase the oral bioavailability of drugs having narrow absorption windows. This research aimed to develop and characterize floating microspheres of metaxalone to address its short half-life and poor bioavailability, thereby enhancing its therapeutic action. Microspheres were prepared by ionotropic gelation with the aid of sodium alginate, ethylcellulose, HPMC, and sodium bicarbonate as a gas-forming agent. The systems were evaluated in a routine manner for micromeritic characteristics, entrapment efficiency, buoyancy, in vitro release patterns, and stability. Physicochemical interactions were studied by FTIR and DSC, whereas morphology was viewed through SEM. The optimized formulation (F5) had 58.43% entrapment efficiency, 81.32% buoyancy, and 82.34% sustained drug release within 12 h. SEM micrographs illustrated spherical particles with hollow cores, and compatibility studies established the lack of drug–polymer interaction. Stability studies showed minimal fluctuation in drug release and buoyancy during the storage time. Metaxalone-loaded floating microspheres had controlled release and extended gastric retention, indicating their usefulness to increase bioavailability, minimize dosing frequency, and enhance patient compliance in the therapy of muscle relaxation. Keywords: Gastro-retentive drug delivery, floating microspheres, oral drug delivery systems, hollow microspheres, bioavailability enhancement.