Pharmacokinetics of sulbenicillin, a new broad‐spectrum semisynthetic penicillin

In a pharmacokinetic study on a new semisynthetic penicillin, α‐sulfobenzylpenicillin, sulbenicillin, serum level, serum half‐life, apparent distribution volume, renal clearance, urinary excretion, and metabolism were determined after a 4‐gm intravenous dose and compared to that of carbenicillin in 5 patients with normal renal function. In the case of sulbenicillin, the mean serum concentration at 1 hr was 157 ± 25 µg/ml, the mean serum half‐life was 70 ± 10 min, the renal clearance was 95 ± 25 ml/min, and the total urinary recovery after 24 hr was about 80% of the dose. The only metabolite detected in the urine was the penicilloic acid derivative, in an amount usually less than 5% of the dose. Serum values, serum half‐life, renal clearances, and excretion pattern did not differ significantly from that of carbenicillin. In 8 patients with decreased renal function (creatinine clearance < 50 ml/min) there was an inverse correlation between creatinine clearance and serum half‐life.