[Studies on the absorption of benzilic acid esters of homologous dimethyl-(2-hydroxyethyl)-alkylammonium bromides through buccal mucosa. 5th communication: On optimum bioavailability of homologous quaternary ammonium compounds (author's transl)].

Distribution studies in vitro predict increasing absorption rates in vivo with increasing distribution coefficients up to a limiting value. Buccal absorption tests with homologous, quaternary cholinesterbromides of benzilic acid do not confirm this hypothesis. The reasons could be the rather hydrophilic properties of the mucosal membranes and thus adsorption of drug to the mucosa. The evaluation of results with undissociated homologous carboxylic acids, however, shows a good correlation between the prediction from in vitro studies and the buccal absorption test.