The Effect of Urinary pH and Flow Rate on the Renal Elimination of Zopolrestat and Zopolrestat Glucuronide in Humans.

Zopolrestat is an aldose reductase inhibitor that may be useful in the treatment of diabetic complications by reducing flux through the polyol pathway. The plasma half-life of zopolrestat in man is approximately 30 h, and approximately 45% of an orally administered 1000-mg dose is eliminated in the urine as unchanged drug. Because active secretion accounts for much of the renal clearance for zopolrestat, a carboxylic acid with a pK(a) of 5.