Ancillin (2-biphenllylpenicillin): Antibacterial activity and clinical pharmacology.

The anti-bacterial spectrum of ancillin was found to be similar to that of other penicillins except that penicillinase-producing strains of Staphylococcusaureus are only slightly less susceptible than non-penicillinase producers. Ancillin appears to be considerably more active than methicillin, as active as oxacillin and nafcillin, and less active than penicillin G (except against penicillinase-producing staphylococci). As with the other penicillinase-resistant penicillins, inoculum size had little or no effect on M. I.C. of ancillin for the organisms tested, except for Bacillus cereus No. 5, for which the M. I. C. increased progressively with increases in the size of the inoculum. Serum increased the M. I. C. considerably due to a high degree of binding of ancillin to serum protein. Absorption and excretion of orally administered ancillin, both in capsules and tablets, varied markedly in normal subjects. Administration orally immediately after a meal resulted in significantly lower levels of activity in the serum and in excretion of a smaller proportion of the drug into the urine; this effect was not overcome by giving the dose with aluminum hydroxide gel. Probenecid given orally increased the levels of activity in the serum after oral and intramuscular doses to bout those produced by twice the corresponding doses, but markedly reduced the amounts recovered in the urine. Procaine hydrochloride included with an intramuscular dose had no significant effect on the absorption and excretion of the ancillin.