LAUSR

Background UK-5099 is a potent mitochondrial acetone carrier inhibitor, that exhibits anticancer activity. Recently, the anti- Toxoplasma gondii activity of UK-5099 was proposed, and in vivo studies of its pharmacokinetics in BALB/c mice are necessary to further evaluate the clinical effect of UK-5099. Methods and results A simple and fast high-performance liquid chromatography-tandem mass spectrometry (HPLC–MS/MS) analysis method was established and verified in terms of its linearity, matrix effect, accuracy, precision, recovery and stability. The analytes were separated by an Agilent ZORBAX XDB-C18 column (2.1 × 50 mm, 3.5 μm) at 30 °C. A gradient mobile phase consisting of water with 0.1% formic acid (FA) (phase A) and acetonitrile (ACN) (phase B) was delivered at a flow rate of 0.40 mL·min −1 with an injection volume of 5 μL. A good linear response was obtained in a concentration range of 5–5000 ng·mL −1 ( r 2  = 0.9947). The lower limit of quantification (LLOQ) was 5 ng·mL −1 . The extraction recovery of UK-5099 was greater than 95%. The inter- and intra-day accuracy and precision of the method showed relative standard deviations (RSDs) of less than 15%. This method has been successfully applied to the pharmacokinetic evaluation of UK-5099 in mouse plasma. In health mice, the main pharmacokinetic parameters of UK-5099 after intraperitoneal administration were measured using a noncompartmental model, in which the AUC 0-t was 42,103 ± 12,072 ng·h·mL −1 and the MRT 0-t was 0.857 ± 0.143 h. The peak concentration (C max ) was 82,500 ± 20,745 ng·h·mL −1 , which occurred at a peak time (T max ) = 0.250 ± 0.000 h. Conclusions A fast and sensitive HPLC–MS/MS method was developed, validated and successfully used for the determination of UK-5099 levels in mice after intraperitoneal administration. This study was the first report of the pharmacokinetic parameters of UK-5099 in mice, which will help to further study the administration of UK-5099 in animals and humans.