Enhanced Mefenamic Acid Release from Poloxamer-Silicon Dioxide GelFilled in Hard Gelatin Capsules - An Application of Liquid Semisolid MatrixTechnology for Insoluble Drug

Introduction: Liquid Semisolid Matrix (LSSM) technology involves the filling of drugmixed gel in hard gelatin capsules for different applications. Methods: In continuation of our previous work on LSSM technology, 10% (w/w) of practically insoluble model drug, mefenamic acid was incorporated in gels of different poloxamers with 8% (w/w) SiO2. Results: Gels exhibited plasticity or pseudoplasticity along thixotropy at 2 and 24 h enabling their easy filling into hard gelatin capsules without content seepage. Mefenamic acid gels prepared with L64 and L92 maintained their apparent viscosities for the study period of one month. Around 100% mefenamic acid was released within 90 min from L64- and in 150 min from L92-SiO2 gels, both with first-order kinetics. In 12 month long-term stability studies, only mefenamic acid-L64- SiO gel at 30°C/65% RH indicated dispersion stability with similar rheology and release pattern to that at 2, 24 and 30 days. No chemical drug-polymer interactions were found in FTIR. Conclusion: The release of practically insoluble mefenamic acid could be enhanced from gel formulated with L64 and SiO2.