Ionisation Constants of Some Penicillins and of their Alkaline and Penicillinase Hydrolysis Products

Abstract

Abstract Ionisation constants of several penicillins and of 6-aminopenicillanic acid in water at 25°, and approximate ionisation constants of the products of alkaline and penicillinase hydrolysis of some penicillins, are presented. The results suggest that mild alkaline hydrolysis of benzylpenicillin is not a simple reaction. The initial product (the penicilloic acid) has the same imino-group ionisation constant as the product of penicillinase hydrolysis, but this ionisation constant decreases after further treatment with alkali. The nature of this effect is discussed.