Formulation of an antispasmodic drug as a topical local anesthetic.

Mebeverine hydrochloride, a spasmolytic agent on GIT smooth muscles, was reported to have a local anesthetic effect. Thus, it was desired in this study to formulate mebeverine HCl into a gel that could be used locally in the treatment of different oral painful conditions. Poloxamer 407 (P-407) was used as the base for this gel. Different additives were used to enhance drug release from the preparation while others were used to enhance the residence time for the preparation. Different formulae were characterized in terms of drug release and mucoadhesion. The formula which has shown the best compromise between the aforementioned parameters was selected for clinical evaluation in comparison to Lidocaine HCl gel and rheologically examined. The best drug release enhancer was cetrimide (0.005%, w/w), while hydroxypropylcellulose (0.5%, w/w) as a mucoadhesive additive has shown the best compromise between fast drug release and mucoadhesion. The gel formula (G) has shown a better pain reduction efficiency (p=0.0078) and longer duration (p=0.0313) than Lidocaine HCl gel. Histopathological examination has shown no change in the inflammatory cells count of rat oral mucosa. Therefore, it could be concluded that (G) is very promising as a local anesthetic preparation for the treatment of different oral painful conditions.