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

• A novel method for quantifying leelamine using LC–MS/MS was developed and validated.
• The method was successfully used in a pharmacokinetic study of leelamine in mice.
• This is the first study to report on bioavailability and pharmacokinetics of leelamine.

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%.