Pharmacokinetics and tissue penetration of ceftibuten

The pharmacokinetics of the cephalosporin ceftibuten were determined after the fifth and final dose of 200 mg given every 12 h. Concentrations in plasma and cantharidin-induced inflammatory fluid were determined by a microbiological assay. Samples for three volunteers were assayed by a high-performance liquid chromatographic procedure to determine levels for both cis and trans ceftibuten. The mean peak level of ceftibuten in serum was 10.9 micrograms/ml at a mean time of 1.8 h after administration, and the mean elimination half-life from plasma was 2.5 h. Penetration into the inflammatory fluid was good, the mean peak level being 9.2 micrograms/ml at a mean time of 3.7 h. The mean percent penetration into the inflammatory fluid was 113.4%. High-performance liquid chromatography analysis showed that the mean peak level of the trans isomer was 5.7% that of the cis isomer. This study suggests that twice-daily doses of ceftibuten should be sufficient to treat urinary or systemic infections caused by susceptible pathogens.