[Pharmacokinetics of ceftriaxone in the peripheral venous serum, uterine arterial serum and intrapelvic genital organs].

The concentrations of ceftriaxone (Ro 13-9904, CTRX) in peripheral venous serum, uterine arterial serum and intrapelvic genital organs were determined by bioassay, using the cylinder-plate diffusion method, in 26 women with simple total hysterectomy. With an intravenous injection of CTRX 1 g, the maximum levels of peripheral venous serum and uterine arterial serum were 116.23 micrograms/ml and 112.76 micrograms/ml, respectively. Also, the biological half-life (T 1/2) was 6.85 hours in peripheral venous serum and 7.31 hours in uterine arterial serum. The concentrations of CTRX in peripheral venous and uterine arterial serum were more than 7.8 micrograms/ml at 24 hours after injection and maintained at a higher level than the minimal inhibitory concentration necessary for most E. coli strains for at least 24 hours. The concentrations of CTRX in intrapelvic genital organs were kept higher than the minimal inhibitory concentration against E. coli at 24 hours after injection, and the ratios of the concentrations in uterine tube and endometrium to that of in peripheral venous serum were 0.474 +/- 0.080 and 0.272 +/- 0.087, respectively. Since CTRX is characterized by more potent antibacterial activity than some other antibiotics and the long-acting efficacy, intravenous administration of CTRX at 1 g or 2 g per day may be an adequate dose for infections of the female urogenital tract.