Penetration of eight beta-lactam antibiotics into the peritoneal fluid. A pharmacokinetic investigation
D. H. Wittman and H. H. Schassan
Serial serum and peritoneal fluid samples were taken after intravenous
injection of cefuroxime sodium, cefoxitin sodium, cefotaxime sodium,
cefoperazone sodium, ceftazidime, moxalactam disodium, mezlocillin sodium,
and piperacillin sodium. Time-concentration curves were obtained for both
pharmacokinetic compartments. The geometric mean of peritoneal fluid
concentrations from eight to ten patients was used to define the
time-concentrations curve for each substance. Serum pharmacokinetic values
were calculated using an open two-compartment model. The concentrations
(Cps) were calculated from peritoneal fluid concentrations by quadratic
interpolation. The time for which one fourth of the Cp (Cp1/4) is
maintained within the peritoneal cavity varied according to the substance
and can be used to estimate dosage intervals. The Cp1/4 was compared with
the minimal inhibitory concentrations for 1,344 pathogens encountered in
415 intra-abdominal infections from 31 studies.