Determination of the Relative Bioavailibilty of Two Brands of Sulfamethazine Powder in ManⅠ

The cumulative urinary excretion of two brands of sulfamethazine powder (A&B) was determined in six healthy men after oral administration of 2 mg of the drug.The results obtained were: the total recovery of A & B in urine was 63.02 &51.98%, the half-life of elimination was 7.16 hr & 7.43 hr, the elimination rate constants, were 0.097 hr_(-1） & 0.093 hr_(-1） respectively.The relative bioavailibility of powder A & B compared to the solution of A was 86.65% & 71.47% respectively, which shows significant difference.