Gas chromatographic determination of the hypoglycaemic agent gliclazide in plasma

A gas chromatographic method has been developed that permits the accurate and specific determination of the hypoglycaemic agent gliclazide in plasma. Gliclazide is extracted with chloroform and, after clean-up, derivatized with diazomethane followed by heptafluorobutyric anhydride to form N-methyl-N'-heptafluorobutyrylgliclazide, which is assayed on a gas chromatograph equipped with a flame ionization detector, an electron-capture detector or a nitrogen-phosphorus sensitive detector. Accurate determinations are possible with flame ionization detection over a concentration range of 1--15 microgram/ml of gliclazide in plasma with a relative standard deviation of 5.2%. The minimum detectable concentration with electron-capture detection is 0.02 microgram per sample. Plasma levels of gliclazide in dogs following single oral administration (40 mg per dog) have also been determined.