Physicochemical Properties and Buccal Absorption of Ethmozine

Kelvin Chan, University of Wolverhampton, United Kingdom

Abstract

The pKa value, partition coefficients between n-heptane-, octanol- and dichloromethane- phosphate buffer, and buccal absorption of ethmozine have been determined. The pKa of ethmozine was 5.65, indicating that it is a very weak base. The partition coefficient between n-heptane and buffer was 0.46, but the drug is almost completely transferred into octanol and dichloromethane with partition coefficients approaching infinity. The buccal aborption of ethmozine increased as the buffer pH increased until a plateau absorption level (around 36%) was reached at pH 7.4. The physicochemical properties and buccal absorption of ethmozine reported in this study should be helpful in understanding its disposition and action in the body. It is likely that the renal elimination of ethmozine would be influenced by urinary pH.