Determination of leelamine in mouse plasma by LC–MS/MS and its pharmacokinetics

Leelamine may be applicable to treat diabetes and is known to inhibit pyruvate dehydrogenase kinase 4. In this study, we developed and validated a quantification method using liquid chromatography (LC) coupled with tandem mass spectrometry analysis, which was applied to a pharmacokinetic investigation in mouse plasma. Leelamine transition ions in multiple reaction-monitoring modes using positive ionization were observed at m/z 286.4 to m/z 173.2. LC was performed using an ACE 5 C18 column, and a mixture of acetonitrile and water containing 0.1% formic acid was used as the mobile phase at a flow rate of 0.22 mL/min. Leelamine and the internal standard (reserpine) had retention times of 4.1 and 3.9 min, respectively. Acceptable linearity (r2 = 0.995) was observed over the concentration range of 10–3000 ng/mL, with a lower limit of quantification of 10 ng/mL in mouse plasma. The intra-day and inter-day accuracy and precision were less than 15%, which was sufficient for quality-control purposes. This method was used to determine leelamine concentrations in mouse plasma and showed that the oral bioavailability of leelamine was 7.6%.