Pharmacokinetics of Ro 13-9904, a broad-spectrum cephalosporin

The pharmacokinetics of the new cephalosporin Ro-13-9904 were studied in six healthy male volunteers receiving a 500-mg dose as a bolus intravenously. Tissue penetration of the antibiotic was estimated by using a cantharides blister method. The data obtained fitted a two-compartment open model. The mean elimination half-life was about 8 h, which is considerably longer than that of other beta-lactam compounds. The distribution volume was 4.3 liters in the central compartment. Levels of Ro 13-9904 in blister fluid exceeded those in serum after 6.5 h. Approximately 60% of the antibiotic was excreted in the urine.