科研之友
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摘要
An HPLC-MS method has been developed and validated for the quantitative determination of milbemycin oxime (MBO) in dog plasma. The developed method has been then applied in in vivo clinical studies to obtain pharmacokinetics of MBO in blood after its oral administration. Samples were extracted using solid-phase extraction (SPE). Sample proteins were precipitated with acetonitrile (ACN) and sodium chloride (NaCl) and then diluted with methanol and water. Calibration standards were prepared by using plasma matrix and following the same SPE procedure. Chromatographic separation was performed on a Waters C-18 packed column (3.5 mu m particles diameter; 3 3 100 mm) with a C-18 guard column (3.5 mu m particles diameter; 3 3 20 mm). The mobile phase was an 85:15 (v/v) mixed solution of ACN and 5 mM ammonium acetate. The calibration curve was linear over a concentration range of 2.0-500 ng/mL with a limit of quantitation of 2.0 ng/mL. The oral administration of a pellet of 2.5 mg MBO produced blood concentrations ranging from 6.10 +/- 0.92 to 78.81 +/- 4.38 ng/mL within 6 h, with a terminal half-time of 11.66 +/- 0.93 h. This study determined the suitability of the herein proposed method to investigate the pharmacokinetics of MBO after oral administration.
