Penetration and clearance of cefoperazone and moxalactam in pleural fluid.

The penetration of cefoperazone and moxalactam into pleural fluid was studied in 11 patients after intravenous infusion of 2-g doses of these agents. Clearance of these agents from pleural fluid was studied in seven patients after instillation of 1-g doses into the pleural space. The concentrations in pleural fluid after intravenous infusion of 2-g doses reached a peak of 7 to 25 micrograms/ml for cefoperazone and 9 to 35 micrograms/ml for moxalactam at 4 to 6 h after administration. These levels exceeded reported MICs for most susceptible organisms. The elimination half-life of both agents was about two to five times longer in pleural fluid than in serum. These prolonged elimination rates of both agents might be of great advantage for killing bacteria in the pleural space.