Simultaneous determination of 15 anti-obesity drugs in blood by high performance liquid chromatography-tandem mass spectrometry

An analytical method for the simultaneous determination of 15 anti-obesity drugs (caffeine; sibutramine, phenformin, etc.) in blood sample was developed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After a simple protein precipitation step, the HPLC separation was performed on an UltimateXB-C ₁₈ column with methanol and 20 mmol/L ammonium acetate (containing 0. 1% (v/v) of glacial acetic acid) as the mobile phases in a gradient elution mode. The MS/MS detection was achieved by electros-pray ionization in both positive and negative modes by rapid switching with selective reaction monitoring (SRM). The results showed that the limits of quantification of all anti-obesity drugs were in the range of 0. 001 -0. 05 mg/L. The calibration curves of all anti-obesity drugs showed good linearity and the correlation coefficients were more than 0. 99. The recoveries of all anti-obesity drugs at 3 spiked levels were in the range of 77. 3%-110. 8% with the intra-day and inter-day precisions less than 12. 3%. The mass spectrum characterizations of 15 anti-obesity drugs were studied. The method is sensitive and reproducible for the detection of the 15 anti-obesity drugs in blood, and can also be applied to the determination of the anti-obesity drugs in Pharmaceuticals or foods.