Determination of apovincaminic acid in human plasma by high-performance liquid chromatography

An isocratic high-performance liquid chromatographic method is described for the quantitative analysis of low concentrations of apovincaminic acid (AVA) in blood plasma. AVA, interfering plasma components and primidone (used as the internal standard) were separated on a reversed-phase column of LiChrospher 60 RP-Select B (125 mm x 3 mm i.d.; 5 microns) (Merck). A UV-Vis detector was used at a wavelength of 254 nm. Each chromatographic separation was completed in 14 min and the results showed a relative recovery which varied between 95.9 and 116%, a good overall precision (relative standard deviation, 7.00%) and sensitivity over a linear range of 5.00-300 ng ml-1 (R = 0.999) for AVA in plasma. The method was applied to the analysis of plasma samples obtained from healthy subjects treated with one single oral dose of 20 mg of vinpocetine. The results indicate the method to be suitable for pharmacokinetic studies.