Tissue penetration of sparfloxacin in a rat model of experimental Escherichia coli epididymitis.

The epididymal, testicular, and prostatic tissue penetration of sparfloxacin, a new quinolone, was assessed in a rat model of acute epididymitis. Seventy-two hours after injection of 0.1 ml (10(6) cfu/ml) of an Escherichia coli suspension into the right epididymis via the right ductus deferens, a single oral dose of sparfloxacin 50 mg/kg body weight was administered. One, 2, 4, 8, 12, and 24 h after administration the animals were sacrificed and the sparfloxacin concentrations and "areas under the curve" (AUC0-24) in both epididymides, both testes, the prostate gland and in the serum were measured by bioassay. The highest mean AUC0-24 was found in the prostate gland, followed by left epididymis, right epididymis, serum, right testis, and left testis (190, 79, 60, 28, 12, and 9 mg/kg x h, respectively). Though there was no statistically significant difference in the sparfloxacin concentration of both epididymides (p = 0.09), the mean AUC0-24 was significantly higher in the non-infected left epididymis (p < 0.0001). The AUC0-24 and sparfloxacin concentrations of the right infected epididymis were significantly higher than those observed in the serum (p < 0.0001). In both testes, the AUC0-24 and sparfloxacin concentrations were lower than in the serum (p < 0.0001), however, the concentration exceeded the MIC tenfold for approximately 20 h. It is concluded that the pharmacokinetic properties of sparfloxacin (good in vitro activity, high penetration into the prostate gland, testes, infected and non-infected epididymides) make this drug a recommendable choice for the initial treatment of acute epididymitis caused by E. coli.