Abstract
For the elucidation on the mechanism of change of methanesulfonated drug in vivo, the rate of hydrolysis was investigated on the derivatives of substituted anilines. In aqueous solution the hydrolysis was found to be reversible between pH 4 and 8 and the rate is pH-independent. The pH-profile of the reverse reaction rate indicated that the formation of methanesulfonic acid derivative occures between molecular aniline and hydroxymethanesulfonate. The electron donating groups facilitate the hydrolysis as well as reverse reaction and the electron attracting groups on the contrarily retard both reactions. Methylation on amino group or C atom of methylene group promotes the hydrolysis significantly. To see the change in rabbit, Na p-phenetidinomethanesulfonate was intravenously administrated and the plasma concentration of intact phenetidine was followed. The curves had maxima which appear within ten minutes. The early maximum would be explained by rapid transference of phenetidine into extravascular fluid or organs. Pharmacokinetic inquiries were given on the processes of the change in blood refering to the data obtained by supplemental studies.
