Polymeric topical film-forming sprays for sustained release of etoricoxib: formulation, optimization, and characterization

The rising prevalence of chronic pain and inflammatory disorders necessitates the development of effective, safe, and patient-friendly drug delivery systems that can improve therapeutic outcomes and patient compliance. Etoricoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, is extensively utilized in the treatment of acute and chronic inflammatory disorders, such as musculoskeletal pain and osteoarthritis; however, traditional oral administration frequently results in gastrointestinal side effects. Therefore, this study aimed to formulate and develop etoricoxib topical film-forming sprays using a quality by design (QbD) approach. Eudragit S-100 and PEG 400 were identified as critical formulation variables, and their influence on viscosity and drying time was systematically evaluated using a response surface methodology (RSM) quadratic model. ANOVA confirmed the significance of both variables, with PEG 400 exerting a dominant effect on drying time and Eudragit S-100 significantly influencing viscosity. The optimized formulations were further characterized. In vitro drug release studies demonstrated sustained release behavior, with 30.68% and 35.26% drug release over 8 h for Batch 1 and Batch 2, respectively. Overall, the findings point out the potential of etoricoxib film-forming sprays as an effective and patient-friendly topical drug delivery system for the management of inflammatory conditions.