Development and evaluation of buccoadhesive tablet for selegiline hydrochloride based on thiolated polycarbophil

Selegiline hydrochloride (SHCl), a monoamine oxidase B inhibitor, is used as an adjunct in the therapy of Parkinson’s disease. This study is concerned with the preparation and evaluation of mucoadhesive buccal tablet for controlled systemic delivery of SHCl. Buccal absorption of selegiline can bypass its first-pass metabolism and improve bioavailability accompanied by greatly reduced metabolite formation, which is potentially of enhanced therapeutic value in patients with Parkinson’s disease. Polycarbophil–cysteine (PCP–cys) conjugate, which is a thiolated derivative of the mucoadhesive polymer polycarbophil, was synthesized by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride-mediated amide bond coupling. Tablets of SHCl based on native and thiolated polycarbophil were prepared. The prepared tablets were evaluated for drug content, swelling behavior, mucoadhesive strength, in vitro drug release, ex vivo permeation and in vitro cytotoxicity. PCP–cys tablets showed enhanced mucoadhesion and retarded drug release compared to polycarbophil tablets. Permeation data of SHCl from matrices prepared using the PCP–cys polymer revealed a significantly higher value of apparent permeability in comparison to polycarbophil, which supported the information in literature that thiolation imparts permeation enhancing properties to mucoadhesive polymers. In vitro cytotoxicity studies on PCP–cys using L-929 mouse fibroblast cell line indicated that conjugation with cysteine does not impart any apparent toxicity to polycarbophil. The results from the study indicate that the buccal delivery of SHCl using thiolated polycarbophil tablet could provide a way for improved therapy of Parkinson’s disease.