Serum and pelvic tissue concentrations of ceftriaxone and cefazolin at hysterectomy

Ceftriaxone and cefazolin concentrations were assayed by high-pressure liquid chromatography in serum and pelvic tissue. Specimens were obtained at uterine removal subsequent to a 1-g intramuscular preoperative dose given to 117 women scheduled for elective vaginal or abdominal hysterectomy. The mean serum concentration of cefazolin was 43.2 ± 13.1 and 39.8 ± 15.4μg/m1 after vaginal and abdominal hysterectomy, respectively. For ceftriaxone they were 59.2 ± 16.8 and 56.1 ± 18.3 μg/m1 for vaginal and abdominal hysterectomy, respectively. Mean tissue concentrations of ceftriaxone were 22.5 ± 10.4, 17.4 ± 6.9, 27.9 ± 10.7, and 16.4 ±6.3 ug/g for vagina, myometrium, fallopian tube, and ovary, respectively, and respective mean tissue concentrations for cefazolin were 15.8 ± 7.6, 14.4 ± 8.5, 15.6 ± 8.0, and 12.4 ± 5.8 pg/g. Pelvic tissue concentrations of cefazolin were similar, but concentrations of ceftriaxone in fallopian tube and vagina were higher than those in ovary and myometrium. Tissue to serum ratios of ceftriaxone remained constant throughout the time intervals studied, whereas cefazolin ratios increased with time.