Mechanistic drug release from cellulose acetate butyrate–palmitic acid-based in situ gels for targeted periodontal therapy via UV–vis imaging

Solvent exchange-induced in situ gels (ISGs) composed of cellulose acetate butyrate (CAB) and palmitic acid (PAL) as matrix forming agents were developed by dissolving in dimethyl sulfoxide (DMSO) and N -methyl pyrrolidone (NMP) for localized moxifloxacin HCl (Mox) delivery in periodontal treatment. The formulations were characterized in terms of viscosity, injectability, mechanical properties, matrix formation, drug release, and antimicrobial activity. UV–Vis imaging was employed to investigate the dynamic processes of solvent transport, drug release, and matrix formation. Combination of CAB and PAL provided acceptable injectability and prolonged drug release. Phase inversion dynamics via UV–vis imaging showed that DMSO based formulations exhibited faster solvent exchange as well as faster drug diffusion as compared to NMP based formulations, which exhibited slower solvent diffusion, leading to more sustained drug release and aligned with matrix formation. Mox-loaded combined CAB and PAL-based ISG demonstrated notable antimicrobial activity against Staphylococcus aureus , Candida albicans , and Porphyromonas gingivalis associated with periodontitis, confirming their potential for periodontitis therapy. This study highlights the critical role of matrix composition, solvent selection, and phase inversion in influencing mechanistic drug release from CAB–PAL ISG for targeted periodontitis therapy as demonstrated through UV–Vis imaging.