Latamoxef (moxalactam) kinetics in volunteers studied by a specific HPLC assay technique

Pharmacokinetic parameters were calculated from plasma and urine latamoxef ('Moxalactam') levels determined by HPLC assay after single and multiple intramuscular (im) and single intravenous (iv) doses of 500 mg given to eight healthy volunteers. After im administration, systemic bio-availability was 92% after both the first and sixth doses. Peak plasma concentration was 18 mg/l (first dose) and 22 mg/l (sixth dose), reached at 1.2 h and 1.3 h respectively. The terminal phase half-lives were 2.5 h and 2.7 h respectively. After iv administration, the initial phase plasma half-life was 0.23 h and the terminal phase half-life, 2.4 h. Plasma clearance was 87.0 ml/min. The steady state distribution volume was 210 ml/kg. After iv administration, 72% of the dose was found in the urine in the first 24 h. Urinary clearance was 66 ml/min (iv dose) and 63 ml/min (sixth im dose). Most systemic infections will permit eight hourly dosing with 500 mg im or iv. Many urinary infections will be best treated with im administration, rather than iv administration.