Engineering Chitosan-Coated PLGA Nanoparticles for Sustained Bupivacaine Delivery: Physicochemical Performance and a Preliminary Fibroblast Cytocompatibility Assessment

Background/Objectives: Bupivacaine hydrochloride (Bupi-HCl) is a widely used local anesthetic; however, rapid diffusion from the site of administration and concentration-dependent cytotoxicity may limit its local therapeutic efficacy. This study aimed to develop chitosan-coated poly(D, L-lactide-co-glycolide) (PLGA) nanoparticles for sustained Bupi-HCl delivery and to evaluate their physicochemical properties, release behavior, long-term stability, and cytocompatibility with fibroblasts.