Abstract
To evaluate the efficacy of gelatin microcapsules containing sulfonamides (sulfanilamide, sulfisomidine and sulfamethizole), blood concentration-time curves were obtained using gastric-emptying-controlled rabbits after intravenous or oral administration of powder and microcapsule dosage forms. Using the pharmacokinetic parameters derived from the intravenous study, the oral administration rate constant for sulfanilamide was calculated and the extent of bioavailability of the microcapsules was compared with that of the powder. It was very hard to obtain a significant advantage with regard to the prolongation effect in the gelatin microcapsules containing sulfanilamide. Similar result was also obtained in the case of sulfisomidine. However, prolonged and sustained release properties were clearly obtained with the microencapsulated sulfamethizole prepared by this method.
