Simultaneous Determination Of Fosaprepitant And Aprepitant In Human Plasma By LC-MS/MS

Background Fosaprepitant is a prodrug of aprepitant,which can rapidly hydrolyzed,metabolized into aprepitant.Aprepitant is a selective NK-1 receptor inhibitor,so as to achieve the efficacy of antiemetic.Clinically,aprepitant is used to treat nausea and vomiting due to chemotherapy.The methods of bioanalysis reported in the literature lack the investigation of the stability of fosaprepitant in human plasma.Objective A liquid chromatography-tandem mass spectrometry(LC-MS/MS)with a short time-consuming,high selectivity,solved the problem of fosaprepitant stability was developed for the simultaneous determination of fosaprepitant and aprepitant in human plasma,so as to improve the pharmacokinetic study of fosaprepitant and aprepitant in healthy Chinese adults,and to provide reference for clinical safety and rational drug use.Method D4-fosaprepitant and d4-aprepitant was used as internal standards(ISs).After a protein precipitation using acetonitrile as the precipitation solvent,analytes and ISs were separated on a Cortex C18+(50×2.1 mm.2.7 ?m)via gradient elution with mobile phase consisting of methanol-10 mmol·L-1 ammonium acetate containing 0.1 mmol·L-1 EDTA at a flow rate of 0.4 mL·min-1 injected into HPLC-MS/MS.The MS/MS detection was performed in multiple reaction monitoring mode (MRM).The precursor to product ion combinations of m/z 613.1?78.9,m/z 617.0?78.9,m/z 533.2?275.1 and m/z 537.2?279.1 were used to quantify fosaprepitant,d4-fosaprepitant,aprepitant,d4-aprepitant,respectively,after chromatographic separation of the analytes.To improve the stability of fosaprepitant in human plasma,the degradation condition of fosaprepitant was inspected,and eventually found the stable condition in the experiment.Results The liner calibration curves for fosaprepitant and aprepitant were obtained in the concentration range of 15.0 to 6000 ng·mL-1 and 10.0 to 4000 ng·mL-1 in human plasma.The intra-day and inter-day precisions and accuracy were within the acceptable limits for all concentrations.To examine the relationship between fosaprepitant blood and plasma samples degradation without any treatment and time at room temperature,4?and-20?.With treatment of 500 mmol·mL-1 ammonium acetate water solution(using ammonia water regulating pH to 9.0),stability of fosaprepitant and aprepitant in human plasma were evaluated after stored at room temperature for 6 h,after stored at-70? and-20? for 93 days.The post-preparative stability was measured after exposure of the processed samples at 4?.Under above storage conditions,the results showed that the plasma samples were stable.Conclusion Stability assessment should cover all relevant conditions encountered in practice.The method has been used in the simultaneous determination of fosaprepitant and aprepitant in human plasma with isotope internal standards.It was suitable for the pharmacokinetic study of fosaprepitant and aprepitant.