Influence of blood proteins on biomedical analysis. XII. Effects of glycation on gliclazide (oral hypoglycemic drug)-binding with serum albumin in diabetics.

The sera of diabetic patients showed an inverse correlation (r=-0.67, n=57) between free gliclazide (oral hypoglycemic drug) level and the fructosamine value. The binding capacity of the primary binding site for gliclazide in the albumin molecule was increased from 4.5×10-4 to 8.0×10-4 M-1 by glycation of albumin, but not that of the secondary binding site (1.2×10-4 M-1). This suggestes that the glycation of albumin increases its total binding capacity for gliclazide, resulting in a low free glicazide level. Therefore, a low hypoglycemic activity of the drug is observed when it is administered to diabetic patients with hyperglycemia.