Pharmacokinetics of Ceftizoxime (FK 749) in Animals after Parenteral Dosing

Abstract

The pharmacokinetic profile of ceftizoxime (CZX. was studied and compared with that of cefotiam, cefmetazole, cefotaxime, cefazolin and cefamandole in mice, rats, dogs and monkeys after a single parenteral dosing. CZX achieved high concentrations in the serum and tissues after parenteral dosing. The serum concentrations of CZX were higher than those of the other antibiotics in large animals (dogs and monkeys), but were lower in small animals (mice and rats). About 80% of CZX was excreted unchanged is a 24-hr period urine of all species tested. The biliary excretion of CZX was low, 3.7% in rats. Pharmacokinetics were analyzed by the two compartment open model using data on serum concentrations is animals after a single intravenous (i. v.) injection. The active substance in urine samples was CZX itself, but small amounts of an active metabolite were detected only in rat bile samples. CZX was stable in biological fluids such as serum, urine and tissue homogenates, but cefotaxime was unstable in rat tissue\omogenates. The serum protein binding of CZX in all species was the lowest of all the antibiotics, i.e. 31 % for humans, 17% for dogs and 32% for rats. © 1980, Japanese Society of Chemotherapy. All rights reserved.