The phannacokinetics and tissue penetration of intravenously administered CGP 31608

The phannacokinetics of CGP 31608, a new injectable penem antibiotic, were studied following a 1 g intravenous infusion. Concentrations were determined in serum, urine and cantharidin-induced inflammatory fluid by a microbiological assay. Peak serum concentrations were achieved at, or before the end of, the 1 h infusion, with a mean of 24-9 mg/1 occurring at 0-8 h. The mean serum elimination half-life was 0-5 h, with no detectable drug in serum after 3 h. Inflammatory fluid was penetrated rapidly with a mean peak level of 10-5 mg/1 occurring at 1-3 h (i.e. 20 min after the end of the infusion). Urinary elimination of CGP 31608 accounted for 52-1 % of the administered dose within an hour of finishing the infusion, and 57-1 % by 12 h. This study suggests that therapeutic serum levels (>8 mg/1) are present for about 1-5 h after starting a 1 h infusion, and in inflammatory fluid for about 2-5 h. Unless a dose in excess of 1 g is used, CGP 31608 will probably have to be given four or more times a day