Abstract
Successively reversible hydrolysis of methanesulfonic acid derivative of sulfisoxazole, R'NHSO2C6H4NHCHRSO3Na (R=CH3 or C6H5), was studied. By the sequential hydrolysis such derivative may be hydrolyzed to the extent that the precipitation of parental drug may take place. The pH-profiles of logarithm of apparent hydrolysis and reverse reaction rates and those of equilibrium constants were obtained and the effect of ionizations of the derivatives and hydrolyzates have been explained by theoretical equations. From the hydrolysis and reverse reaction rates estimated, reaction pathway of individual reactions which compose whole hydrolysis system has been discussed.
