Factors Influencing the Formation of Sulfonamide Urinary Concretions

Abstract

The deposition of sulfonamide concretions in the urinary tract depends upon: (1) concentration of the drug; (2) degree of acetylation of the sulfonamide; (3) urinary stasis; (4) pH of the urine; and (5) temperature of the urine. The authors investigated the influence of the pH and of the temp. of the urine on the saturation point of sulfathiazole and sulfadiazine. Urine specimens were obtained from patients ingesting large doses of sulfathiazole or sulfadiazine. The urines were saturated with the drug. The pH of each specimen was adjusted by adding dilute HC1 or dilute NH40H to values ranging from 5.0-8.0. Parallel tests were carried out at 78.8[degree]F., at 98[degree]F., 99[degree]F. and so forth up to 105[degree]F. All specimens were kept for 24 hrs. and the conc. of the drug was detd. The expts. revealed that as the pH of the urine is increased and the temp. of the urine is elevated, the solubility of sulfathiazole and sulfadiazine is heightened. This range is from a sulfathiazole conc. of 78.1 mg/100 cc at a pH of 5.0 and temp. of 78.8[degree]F. to a conc. of 250.0 mg per 100 cc at a pH of 8.0 and temp. of 105.0[degree]F. The range for sulfadiazine is from 69.6 mg per 100 cc to 170.4 mg per cc. The significance of the findings is discussed.