CLOXACILLIN

one of several semisynthetic penicillins, so called because they are made by the addition of a specific substance to the medium in which a culture of Penicillium mold is growing. Semisynthetic penicillins have been developed in attempts to circumvent disadvantages of penicillin G. The antimicrobial activity of cloxacillin is similar to that of penicillin G, but it is more resistant than penicillin to inactivation by penicillinase, an enzyme (biological catalyst) occurring in many microorganisms.