Abstract
Sulfisomidine, sulfamethizole and their biotransformed products in man (N4-acetate, N4-glucuronide, N4-sulfonate) were applied to renal clearance experiments in dogs and protein binding experiments to dog plasma protein in order to elucidate their renal excretion mechanisms.
Clearance ratio of N4-acetate of both sulfonamides were less than that of original sulfonamides. From the results of inhibitory experiments by iodopyracet, it was found that both sulfonamides and their N4-acetates were actively secreted and N4-glucuronides exhibited reduced proximal tubular secretion. It was observed that clearance ratio of sulfamethizole-N4-glucuronide, in spite of the reduced affinity for plasma protein and increased solubility, were lower than that of sulfamethizole.
