The effect of vitamin C in the formulation of pectin/thiolated alginate buccal adhesive patches: In vitro and Ex vivo evaluation

The present study outlines the prospect of a pectin (Pec)/modified alginate (Alg) buccal patch as drug delivery device in the localized treatment of oral cavity diseases. Firstly, Alg was modified with acrylic acid, and thiolated with cystein to enhance its mucoadhesive properties. Then modified Alg was characterized with Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1HNMR) spectroscopy. As a proof of concept, Pec/modified Alg buccal patches were formed via the conventional solvent casting technique. Then the patches were characterized by FTIR and differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA). Vitamin C (Vit C) was used for in vitro drug release assay, and the release amount was 2.10 mg/g polymer in simulated salivary pH 6.8. Ex vivo mucoadhesion assays of Vit C loaded Pec/modified Alg patch did not have a negative effect on the mucoadhesion feature of the material. The cytotoxicity study indicated that Pec/modified Alg buccal patches did not exhibit apparent cytotoxicity against NIH/3T3 cell lines. Notably, it was found that Vit C in the patch formulation has an accelerating effect on wound healing. According to all results, Vit C loaded Pec/modified Alg buccal patch might be a promising candidate for localized buccal drug release systems.