Inhibition of sorbitol formation in human erythrocytes by calcium dobesilate

The effects of calcium dobesilate (Doxium, a drug already known to prevent or reverse the retinal microvascular lesions of diabetes mellitus) on sorbitol formation in human erythrocytes was studied, and compared with the effects of tetramethylene glutaric acid (TMGA), a specific aldose reductase inhibitor. Both compounds inhibited sorbitol formation. In a 29 mmol/l glucose medium, calcium dobesilate in concentrations of 2 and 10 mmol/l caused, 50 and 100% inhibition of sorbitol formation, respectively, whereas TMGA completely inhibited sorbitol formation at a concentration of 0.1 mmol/l. These results suggest that calcium dobesilate may exert, at least in part, its beneficial effect on diabetic microangiopathy by inhibiting the formation of sorbitol. The inhibition of sorbitol synthesis may be mediated by an inhibitory action of calcium dobesilate on aldose reductase.