Quantification of an alkylphosphocholine antitumor agent in plasma by pneumatically assisted electrospray: Tandem mass spectrometry coupled with high-performance liquid chromatography

An on-line high-performance liquid chromatography assay with tandem mass sp ectrometric detection in the positive-ion Turbo-Ion-Spray(TM) mode for the fast and sensitive determination of perifosine (D-21266) in human plasma wa s developed using the structural analog miltefosine (D-18506) as internal s tandard. Automated solid phase extraction of diluted plasma samples, based on 250 mu l plasma aliquots, at pH 6.5, allowed a reliable quantification o f perifosine down to a quantification limit of 4 ng/ml. Injection of 200 mu l of plasma extracts onto a 100 mm x 3 mm normal-phase analytical column a t a flow-rate of 0.5 ml/min provided retention times or 2.4 and 2.1 min for perifosine and the internal standard, respectively. The standard curves we re linear from 4-2,000 ng/ml using weighted linear regression analysis (1/Y -2). The interassay and intraassay accuracies for the calibration standards were +0.9% and -0.2%, exhibiting precisions (coefficient of variation) of +/-6.5% and +/-7.3%, respectively. Up to 100 unknowns were able to be analy zed every 24 h per analyst. (C) 1998 Prous Science. All rights reserved.