Determination Of Nifedipine And Dehydronifedipine In Human Plasma By LC-MS/MS And The Study Of Drug Interaction

Background Nifedipine is a dihydropyridine calcium antagonist,which is mainly used in the treatment of angina pectoris and hypertension.Nifedipine is mainly metabolized by CYP3A4 enzyme to form its metabolite dehydronifedipine.When CYP3A4 enzyme is induced or inhibited,the pharmacokinetics of CYP3A4 substrates?such as nifedipine?may change significantly.In vitro,Apatinb a anti-tumor drug,has been shown to inhibit CYP3A4 enzyme.Objective A rapid and sensitive LC-MS/MS method was developed to simultaneously determine nifedipine and dehydronifedipine in human plasma.The validated LC-MS/MS method has been successfully used to study pharmacokinetic interactions of apatinib a targeted anti-tumor drug and nifedipine in humans,providing a basis for rational clinical medication.Method D₆-nifedipine/d₆-dehydronifedipine was used as the internal standard.After extraction from the plasma by protein precipitation,the analytes and internal standard were sepatated on a Hypersil Gold C₁₈?50 mm×2.1 mm,1.9?m?.The mobile phase consisted of methanol and 5 mmol·L^-1 ammonium acetate aqueous solution?0.1%formic acid?.Gradient elution was used,0-0.3 min,40%methanol;0.3-1.0 min,40%-70%methanol;1.0-2.0 min,70%methanol;2.0-2.1 min,70%-40%methanol;2.1-3.0min,40%methanol.Positive electrospray ionization was performed using multiple reaction monitoring?MRM?with transitions of m/z 347.3?254.1 for nifedipine,m/z 345.2?283.9 for dehydronifedipine,m/z 353.3?257.1 for d₆-nifedipine and m/z 345.2?283.9 for d₆-dehydronifedipine.This clinical trial was approved by the Ethics committee and conducted in the First Hospital of China Medical University.Results The linear range of the standard curve of nifedipine was 0.100-80.0ng·mL^-1,and the linear range of the standard curve of dehydronifedipine was0.050-40.0 ng·mL^-1.Compared with the reported methods,the chromatographic separation was improved and the detection sensitivity was significantly improved.This method has been successfully applied to study the drug interaction between nifedipine?CYP3A4 substrate?and apatinib?CYP3A4 inhibitor?in human plasma.When coadministered with apatinb,the C_max of nifedipine was 1.58-fold higher than administering nifedipine alone,and the AUC_0-t of nifedipine was 1.63-fold higher than administering nifedipine alone.When coadministered with apatinb,the C_max of dehydronifedipine was 1.01-fold higher than administering nifedipine alone,and the AUC_0-t of dehydronifedipine was 1.09-fold higher than when administering nifedipine alone.Conclusion The methods were proved to be highly sensitive,selective and suitable for the pharmacokinetic study of nifedipine and dehydronifedipine.Results show that aptinib has a weak drug-drug interaction with nifedipine,but if need to adjust the clinical dosage of nifedipine,more data are needed to support.