Chitosan/pvp-based mucoadhesive membranes as a promising delivery system of betamethasone-17-valerate for aphthous stomatitis

Mucoadhesive membranes were proposed in this study as drug delivery system for betamethasone-17-valerate (BMV) in the treatment of recurrent aphthous stomatitis (RAS). The membranes were obtained by using the polymers chitosan (CHI) in both presence and absence of polyvinilpyrrolidone (PVP), following the solvent evaporation method. The presence of PVP in the membranes causes significant modifications in its thermal properties. Changes in the thermal events at 114 and 193 degrees C (related to BMV melting point), and losses in mass (39.38 and 30.68% for CH: PVP and CH: PVP-B, respectively), suggests the incorporation of BMV in these membranes. However, the morphological aspects of the membranes do not change after adding PVP and BMV. PVP causes changes in swelling ratios (> 80%) of the membranes, and it is suggested that the reorganization of the polymer mesh was highlighted by the chemical interactions between the polymers leading to different percentages of BMV released similar to 40% and similar to 80% from CH-B and CH: PVP-B. BMV release profile follows Korsmeyer and Peppas model (n > 0.89) which suggests that the diffusion of the drug in the swollen matrix is driven by polymer relaxation. In addition, the membranes containing PVP (higher swelling ability) present high rates of tensile strength, and therefore, higher mucoadhesion. Moreover, given the results presented, the developed mucoadhesive membranes are a promising system to deliver BMV for the treatment of RAS.