HPLC analysis of plasma glipizide and its application to pharmacokinetic study

Glipizide is an oral hypoglycemic agent widely used to treat type 2 diabetes mellitus. In this study, an efficient HPLC-UV assay method for determining the plasma glipizide level was developed, validated, and used to assess the pharmacokinetic profile of the glipizide in healthy Korean volunteers. After extraction with diethyl ether, the chromatographic separation of glipizide was carried out using a Bondclone C18 column (10m, 3003.9mm) with a mobile phase of 10mM potassium phosphate monobasic and methanol (40:60 [vol/vol], pH 3.5) and UV detection at 225nm. The flow rate of the mobile phase was 1.0mL/min and the retention time of glipizide and internal standard (I.S.) was approximately 11.5 and 8.6 minutes, respectively. The quantification limit was 15ng/mL and the linear range of the calibration curve ranged from 15 to 800ng/mL in plasma with a correlation coefficient 0.9999. The mean accuracy was 86-101%. The coefficient of variation (precision) in the intra- and inter-day validation was 1.8-14.2 and 1.7-8.1%, respectively. The pharmacokinetics of oral glipizide was evaluated after administering 5mg to each of 13 healthy Korean subjects. The AUCinf, Cmax, Tmax, and T1/2 were 3432886ngh/mL, 629.094.2ng/mL, 2.81.8h, and 3.90.9h, respectively. The results showed large inter-individual differences in the AUCinf, Cmax and T1/2.