Formulation and Characterization of Captopril-Loaded Chitosan Mucoadhesive Buccal Films with Different Permeation-Enhancing Components

Background/Objectives: The buccal mucosa offers a promising non-invasive route for systemic drug delivery, particularly for hydrophilic compounds like captopril (CAP), which exhibit low permeability and are subject to gastrointestinal instability and first-pass metabolism. This study aimed to develop and characterize captopril-loaded, chitosan-based mucoadhesive buccal films with different permeation enhancers and to evaluate their physicochemical properties, drug release, cytocompatibility, and in vitro transport across a TR146 buccal epithelial cell model. Methods: Films were prepared by the solvent-casting method using chitosan as the film-forming polymer. Different enhancers were investigated, including organic acid salts of chitosan (ascorbate, citrate, and lactate) and chemical permeation enhancers (sodium lauryl sulfate, polyethylene glycol 400, Span 20, and EDTA). Results: The resulting films exhibited acceptable thickness, moisture content, appropriate mechanical properties, and good mucoadhesive strength. In vitro dissolution studies demonstrated rapid CAP release, with >50% released within 15 min and near-complete release by 180 min across all formulations. Cytotoxicity assessment via a Neutral Red uptake assay in TR146 cells confirmed high cell viability (>81%) after 4 h of exposure, indicating good biocompatibility. In vitro permeation experiments revealed that films prepared with chitosan ascorbate and chitosan lactate enhanced CAP transport compared to other formulations, achieving the highest flux and apparent permeability coefficients. Conclusions: These findings demonstrate that chitosan ascorbate and lactate salts effectively improve the buccal permeability of captopril while maintaining good film properties and biocompatibility. This work highlights the potential of chitosan ascorbate- and lactate-based mucoadhesive films as an efficient platform for the buccal delivery of CAP.