The effect of sodium pyruvate on the elimination of sulfadiazine in slow acetylation rabbits

The purpose of this study was to investigate the mechanism by which pyruvic acid (PA) affects the pharmacokinetics of sulfadiazine (SDZ) and its metabolite, acetylsulfadiazine (AcSDZ) in slow acetylation rabbits. After IV bolus administration of equal molar doses of SDZ (20 mg/kg) and AcSDZ to rabbits during infusion of 0.9% NaCl or PA, the plasma concentrations of both SDZ and AcSDZ were quantitated by an HPLC method. The results showed that the elimination of SDZ in slow acetylation rabbits was significantly increased (p <0.05) when the plasma PA concentration was maintained at ≃ 100 μg/mL. In addition, the area under the plasma concentration-time curve (AUC) of AcSDZ formed from SDZ was significantly decreased (p <0.005). The formation fraction (F) of AcSDZ formed from SDZ was also significantly decreased from 0.28 ± 0.08 to 0.13 ± 0.04 (p <0.005). However, the pharmacokinetics of AcSDZ after IV bolus administration were not changed during PA infusion. The renal excretion of SDZ was significantly increased (p <0.005) in PA infused rabbits, indicating that the change in SDZ elimination in slow acetylation rabbits during PA infusion was primarily due to increased renal excretion.