Reversed-Phase High-Performance Liquid Chromatographic Determination of Gliclazide in Human Plasma

A high-performance liquid chromatography (HPLC) procedure was developed for the determination of plasma gliclazide, a new oral hypoglycemic drug. Gliclazide, tolbutamide (used as an internal standard) and plasma components in plasma were successfully separated as sharp peaks by reversed-phase HPLC on a Jasco SC-01 column with methyl alcohol containing 0.2% acetic acid (3 : 2, v/v) as the mobile phase (retention time ; gliclazide : 16 min, IS : 10 min, plasma components : 5.5 and 7.0 min). The relationship between the plasma levels of gliclazide and the peak height ratio (gliclazide/IS) was linear (correlation coefficient, γ=1.00) in the range of 0.3 to 10 μg/ml plasma. The detection limit and the reproducibility (CV) of the present method were 0.3μg/ml and 4.0% (n=8), respectively. The decay curve of plasma gliclazide in a diabetic patient given 80 mg of the drug orally was determined by the present method and GLC (ECD method). The two results agreed well. Reversed-phase HPLC was shown to be suitable for the routine clinical assay of gliclazide in plasma.