Experimental models for determination of antimicrobials in prostatic tissue, interstitial fluid and secretion.

Two new animal models were used to evaluate the usefulness of several antimicrobials for the treatment of bacterial prostatitis. An experimental bacterial prostatis was created in dogs and the concentraion of six antimicrobials (erythromycin, rosamicin, trimethoprim, sulphamethoxazole, ampicillin and doxycycline) measured in plasma and prostatic secretion and their concentration ratios compared to previous studies in healthy dogs. Prostatic interstitial fluid concentrations of the three basic drugs (erythromycin, rosamicin, trimethoprim) were determined from samples obtained from implanted tissue chambers. At the same time samples of plasma, prostatic secretion and urine were collected and their concentration ratios compared. Drug levels in prostatic secretion of dogs with infected prostatic glands were different from those without inflammation, but the same mechanism of drug diffusion into the prostatic secretion seems to be active during infection. Prostatic interstitial fluid concentrations of the three basic drugs were always lower than the simultaneous prostatic secretion levels. These findings may have clinical application in the treatment of bacterial prostatitis.