Use of solid phase extraction in quantitative determination of gliclazide in human serum by HPLC

Solid phase extraction (SPE) for isolation of gliclazide from serum was used. A reverse-phase high-performance-liquid-chromatography procedure RP-HPLC was developed. Glibenclamide was applied as an internal standard. Gliclazide, the internal standard, and endogenous substances were separated using a liquid chromatograph equipped with RP-18 column 10 mu m by means of a mobile phase acetonitryl-0.04 mol l(-1) KH2PO4 [49:51 (V/V)], pH = 3.8 and measured at lambda(max) = 229 nm. 0.25 ml of sample serum was sufficient for the analysis of gliclazide. A linear calibration curve was obtained in the range from 0.2 to 10 mu g ml(-1). Gliclazide mean concentrations found in the human serum after administration of a 80 mg tablet were in the range 0.52-3.58 mu g ml(-1). The total recovery of gliclazide added to serum to obtain its concentration 4 mu g ml(-1) was 75.3 +/- 4.5%. The precision of the method expressed by coefficient of variation (C.V.) was 6.2%. The HPLC method with SPE was applied for pharmacokinetic and bioavailability studies of gliclazide.