Physicochemical and antimicrobial evaluation of chitosan and hydroxypropyl methylcellulose films for prolonged release of pilocarpine

Introduction: The use of prolonged local drug delivery to the oral cavity offers multiple benefits, such as increasing the pharmacological action in the desirable local site and reducing the usual dose and the adverse effects. Pilocarpine is a cholinergic drug approved by the FDA for the treatment of glandular hypofunction; however, the extent of its adverse effects limits its use. Objective: The main aim of this study was to analyze the physical and chemical properties of films, including pH, thickness, solubility, consistency and the ability to release pilocarpine for a prolonged time. Additionally, the antimicrobial activity in two opportunistic pathogens in hyposialia (Streptococcus mutans and Candida albicans) was also assessed. Methodology: Chitosan and HPMC (Methocel K4M CR) films were prepared in 1% acetic acid and pilocarpine was added under magnetic stirring. PH, thickness and time of solubility in artificial saliva, as well as diffusion and drug release kinetics per cm2 (OD=420nm) were assessed by spectrophotometry. The antimicrobial activity was tested by disk diffusion test against St. mutans ATCC 700610 and C. albicans ATCC 90029 at concentrations of hyposalivation (1.44x1.2x106 CFU and 103 CFU, respectively). Results: All the films, except for Hydroxypropyl methylcellulose / Pilocarpine formulation, were found to have optimal physical-chemical properties for handling, maintaining drug diffusion in 76% per cm2 for four hours extended-release without showing antimicrobial activity at concentrations of hyposalivation. Conclusion: The films had optimum handling properties and a constant drug release; however, antimicrobial activity was not found.