Penicilloic acid

Penicilloic acid is any of several acids which are obtained from the penicillins by the hydrolytic opening of the lactam ring (as by the action of a beta-lactamase). Hypersensitivity is the most important adverse effect of the penicillins. The major antigenic determinant of penicillin hypersensitivity is its metabolite, penicilloic acid, which reacts with proteins and serves as a hapten to cause an immune reaction.