Comparison of cefoperazone and cefoxitin concentrations in serum and pelvic tissue of abdominal hysterectomy patients

Cefoperazone and cefoxitin concentrations were determined in serum and pelvic tissue samples obtained at various intervals after a 2-g intramuscular dose. These levels were determined in 59 women scheduled for elective abdominal hysterectomy. Concentrations were measured by a new high-pressure liquid chromatography method which correlated with the microbiological assay. The mean times (± standard deviation) of specimen collection were 188.5±61 and 185.5±55 min for cefoperazone and cefoxitin, respectively. The mean serum levels (± standard deviation) were 60.8±18.0 and 14.6±8.6 μg/ml, respectively. For cefoperazone, the mean pelvic tissue concentration was 19.8 μg/g. The mean pelvic tissue concentration for cefoxitin was 7.8 μg/g. The ratio of tissue concentration to serum concentration varied from 0.220 to 0.469 for cefoperazone and from 0.176 to 1.031 for cefoxitin. Although the serum and tissue concentrations of cefoperazone were much higher than those of cefoxitin, a greater portion of cefoxitin remained in the tissue. The tissue levels of both cefoperazone and cefoxitin were above the minimum inhibitory concentration of most sensitive pathogens several hours after a single prophylactic dose of either antibiotic.