Zopolrestat (CP73850) is a potent, orally active aldose reductase (AR) inhibitor with an IC50 of 3.1 nM. Zopolrestat is used for the research of diabetic complications.In Vitro: Zopolrestat is a potent inhibitor of the reduction of both glyceraldehyde and glucose by the human and rat enzymes.In Vivo: Zopolrestat (2.5 mg/kg-50 mg/kg; p.o.; once-a-day for 5 days) and left untreated for 7 days) prevents accumulation of sorbitol in the kidney cortex of diabetic rats and normalize elevated renal blood flow in galactosemic rats.