Concentrations of pefloxacin in plasma and tissue after administration as surgical prophylaxis.

Plasma and epiploic-fat drug concentrations determined by high-performance liquid chromatography and fat penetration of pefloxacin and its metabolite (norfloxacin) given for antimicrobial prophylaxis were studied in patients scheduled for colorectal surgery. Concentrations of pefloxacin in plasma decreased about 40% from the beginning of the operation to closure of the peritoneum, and corresponding levels in epiploic fat stayed stable. The plasma and tissue norfloxacin concentrations were very low. Concentrations of pefloxacin in tissue were greater than MIC at which 90% of isolates are inhibited for sensitive bacteria (members of the family Enterobacteriaceae). The penetration of pefloxacin into epiploic fat was about 32%.