Bioavailability of sulfadiazine solutions, suspensions, and tablets in humans

A four-way crossover sulfadiazine bioavailability study was conducted in 16 normal healthy male volunteers. The subjects were divided into groups of eight. Each group received four different oral dosage forms of sulfadiazine at 1-week intervals: a solution as a reference, a suspension, and two different tablets. All dosage forms were equivalent to 500 mg of sulfadiazine. Blood samples were obtained at 0, 0.5, 1.0, 2.0, 3.0, 4.0, 6.0, 8.0, 10.0, 25.0, 33.0, and 49.0 hr. Analysis of variance indicated no statistically significant difference (p more than 0.05) between the dosage forms in terms of area under the plasma level--time curve, peak plasma concentration, and time of peak plasma concentration. In both groups, there were differences between products at isolated sampling times. It was concluded that the four tablet formulations of sulfadiazine exhibited bioavailability characteristics equivalent to those of the solution and the suspension.