SRP. 2020; 11(1): 165-173
Development, Validation, and Application for Simultaneous Assay of Amlodipine, Atorvastatin, and Ortho- and Para Hydroxy Atorvastatin as Metabolites in Human Plasma by Liquid Chromatography Tandem Mass SpectrometryChuong Ngoc Nai, Nguyen Van Trung, Tran Long Thai, Nguyen Ngoc Vinh, Tran Viet Hung, Pham Van Son, Nguyen Duc Tuan.
Background: The objective of this study was to develop a liquid chromatography tandem mass spectrometry (LC-MS/MS) method to quantify amounts of amlodipine, atorvastatin, and two metabolites of atorvastatin (ortho- and para-hydroxy atorvastatin) in human plasma and to apply this method for a bioequivalence study.
Methods: An LC-MS/MS method was developed, validated, and applied to quantify amlodipine, atorvastatin and two metabolites of atorvastatin (ortho- and para-hydroxy atorvastatin) in human plasma. Rosuvastatin was used as an internal standard. LC-MS/MS with electrospray ionization (ESI) in positive ion mode, performed under the multiple reaction monitoring (MRM) mode, was used to analyze the analytes.
Results: The method was developed and fully validated with respect to selectivity, carryover, dilution integrity, and intra- and inter-day accuracy and precision according to US Food and Drug Administration (FDA) guidelines. Analytes were extracted from human plasma via a simple liquid-liquid extraction technique using a mixture of methyl tert-buthyl ether and ethyl acetate (1:1) after acidification with phosphoric acid. Mean extraction recovery for the analytes was between 70% and 99.95%, and matrix effects had only minor influence on precision.
Conclusion: The validated method was applied for a clinical bioequivalence study to evaluate the in vivo bioequivalence of two commercial products containing 5 mg amlodipine and 10 mg atorvastatin. 36 healthy subjects participated in this randomized, two-period, two-treatment, open label, crossover design study. Standard pharmacokinetic parameters were calculated to compare a test product to the CADUET® reference product. it is concluded that the two formulations are bioequivalent.
Amlodipine; Atorvastatin; Ortho- and para-hydroxy atorvastatin; LC-MS/MS; Bioequivalence