Application of Gas-Liquid Chromatography (GLC) for the Determination of Plasma Tolbutamide and Chlorpropamide in Diabetics

(2) Clinical Results

Abstract

Clinical application of our improved GLC method for estimating tolbutamide and chlorpropamide levels in the plasma is described.
The procedure was used to examine the plasma of 83 diabetics under treatment with tolbutamide (n=53) or chlorpropamide (n=30). The following results were obtained 1) The correlation coefficients between the amount of drugs administered orally and the basal plasma levels of the drugs were 0.64 and 0.61 for tolbutamide and chlorpropamide, respectively. 2) There was no significant difference in basal sulfonylurea levels between those administered the drugs for more than 10yr and those for less than 5yr. 3) The basal plasma chlorpropamide levels in diabetics using 0.5 g of chlorpropamide were significantly correlated with the degree of obesity (r=0.81, p<0.05). 4) Good responders, i.e. those whose FBS levels decreased withincrease in plasma tolbutamide levels, amounted to 7 in 8 diabetics (88%), 5 in 12 diabetics, (42%), and 1 in 7 diabetics (14%), whose daily doses were 1.0 g, 0.5 g. and 0.25 g of tolbutamide, respectively.
The above findings are discussed according to a proposed pharmacodynamic model involving a two-compartment system.