Rapid extraction, identification and quantification of oral hypoglycaemic drugs in serum and hair using LC-MS/MS.

A sensitive and accurate LC-MS/MS method for the identification and quantification of 5 oral anti-diabetics (glipizide, glibenclamide, gliclazide, gliquidone and metformin) in serum and hair was developed using glibornuride as the internal standard. We have developed a rapid and robust extraction procedure by using acetonitrile for serum protein precipitation and methanol for the extraction of anti-diabetics from hair. Anti-diabetics (ADs) were separated by UPLC over a C18 column and detection was performed on a Waters Xevo TQ MS mass spectrometer in positive ionization mode using electrospray ionization. Each AD was identified by three specific ion transitions in multiple reaction monitoring (MRM) mode. The method was validated according to international guidelines. For all compounds the variation coefficient (CV) was <20%, and accuracies ranged from 85 to 115% in serum and hair. The limits of detection (LODs) were <1.5 ng/mL for all ADs in serum and <3.59 pg/mg in hair. Recoveries varied from 56.41% (gliclazide) to 67.58% (glipizide) in serum and from 68% (gliclazide) to 91.2% (metformin) in hair. The method was successfully applied to quantify ADs in serum of 33 patients and in hair of 15 patients.