Combined cellulose acetate butyrate and palmitic acid solvent exchange-driven phase inversion in situ gel loading moxifloxacin HCl for periodontitis therapy

This study develops in situ forming gels (ISGs) incorporating cellulose acetate butyrate (CAB) and palmitic acid (PAL) as matrix-forming agents for localized periodontal drug delivery. The aim is to investigate the effects of CAB, PAL, and their combination on viscosity, rheological behavior, matrix formation, drug release, structural properties, and antimicrobial efficacy of moxifloxacin (Mx)-loaded ISGs. Drug release was examined, and release kinetics were determined using mathematical modeling. Scanning electron microscopy (SEM) and X-ray tomographic microscopy (XTM) were used to characterize matrix structures. Antimicrobial activity was assessed against Staphylococcus aureus, Candida albicans, and Porphyromonas gingivalis over 14 days using an agar diffusion assay. CAB dominant ISGs formed dense, slow-releasing matrices, while PAL dominant ISGs exhibited rapid phase inversion due to swift solvent exchange and higher porosity. NMP-based ISGs formed more porous matrices than DMSO-based ISGs in PAL-dominant formulations, enhancing drug diffusion at later stages. CAB/PAL combination ISGs balanced injectability, phase inversion, and prolonged drug release. Antimicrobial studies also confirmed sustained activity, with CAB dominant formulations maintaining efficacy for 14 days. CAB/PAL-based ISGs offer a promising strategy for sustained periodontal drug delivery while solvent selection modulates porosity and antimicrobial activity. This system demonstrates potential for prolonged therapeutic efficacy in localized periodontal treatment.