Stability of Atropine in Aqueous Solution

A kinetic study of the proton catalyzed hydrolysis of atropine has been carried out and the temperature dependency of this reaction established. The constants obtained for this reaction have been combined with those previously reported for the hydroxyl catalyzed reactions and an equation proposed to predict the half life of atropine undergoing hydrolysis at constant pH and temperature. The pH of minimum hydrolysis has been calculated and found to vary with temperature from pH 4.11 at 0° to pH 3.24 at 100°. Calculated half lives of atropine in solution over the region of pH 2 to 7 at temperatures from 20° to 100° are given.