Studies on the effect of free fatty acid on binding of benzyl-penicillin by serum proteins.

An effective level of penicillin in serum of healthy individuals is maintained for 6, 8 and 10 hours after oral administration of single doses of 260, 325 and 385 mg of potassium penicillin G respectively. Regardless of variations of doses the antibiotic peak level is achieved one hour after oral administration. Palmitic acid stimulates serum protein and albumin binding of penicillin G. The increased binding of penicillin G with whole human serum in the presence of fatty acid is due to the influence of the latter on the albumin fraction of the serum. Dexamphetamine administration to healthy individuals produces a stimulation of penicillin binding by serum protein which is due to an increase of the free fatty acid (FFA) concentration in blood.