Study on Bioavailability of Sulfadiazine Tablets in Man

Abstract

Sulfadiazine Tablets USP, 500 mg, from 3 different manufacturers were tested in vitro and in vivo. Dissolution rate and disintegration time were measured in water, artificial gastric fluid, and artificial intestinal fluid. Disintegration and dissolution were fastest in artificial gastric fluid. Product I was superior in disintegration to the other two products, whereas product 2 was superior in dissolution. The in vivo study was designed as a Latin square so that each of the 3 treatments was given to each of the 3 subjects at each of the 3 time periods. Two-way analysis of variance was done using the cumulative urinary excretion of free and total sulfadiazine after 24 and 120 hours. Although the extent of bioavailability of product 1 and 2 was only 78 and 73 percent, respectively, statistically significant differences were found only at 24 hours. Judging from both rate and extent of bioavailability, product 3 was superior to products 1 and 2. The difference between in vitro and in vivo data is noted.