Distribution of quinoline carboxylic acid derivatives in the dog prostate

The distribution in the prostate of norfloxacin and rosoxacin, both quinoline carboxylic acid derivatives, was investigated in an experimental dog model. The concentrations in prostatic interstitial fluid (PIF) and prostatic secretion (PS) of both antimicrobials were lower than the corresponding plasma (P) concentrations, as might be expected for acidic compounds. Norfloxacin achieved significantly higher PS/P and PIF/P ratios than rosoxacin following intravenous infusion; there were no differences between the two drugs in the various tissue/plasma ratios. The concentrations of both norfloxacin and rosoxacin in PIF, PS, and urine were in the minimal inhibitory range for most gram-negative pathogens causing bacterial prostatitis and urinary tract infections. Clinical trials may be warranted for both drugs.