UHPLC-MS/MS method for determination of atorvastatin calcium in human plasma: Application to a pharmacokinetic study based on healthy volunteers with specific genotype

A rapid, selective and sensitive ultra high performance liquid chromatography coupled with tandem triple quaternary mass spectrometry (UHPLC-MS/MS) method was developed and validated for the quantitative determination of atorvastatin calcium (AC) in human plasma. Separation of AC and rosuvastatin calcium (internal standard, IS) were achieved on a Dikma Leapsil C18 reversed phase column (100 x 2.1 mm, 2.7 mu m) with gradient elution using 0.2% (v/v) formic acid in water and acetonitrile as mobile phases, at the flow rate of 0.3 mLimin. AC and IS were detected using MS/MS with turbo ion pray source in negative mode by monitoring the precursor-to-product ion transitions m/z 557.0 -> 453.0 for AC and m/z 480.0 -> 418.0 for IS. The calibration curves were linear from 0.05 to 50 ng/mL with a correlation coefficient (r(2)) of 0.9992 or better. Thereafter, 187 healthy candidates were checked to the genetic polymorphism analysis of SLCO1B1 521T>C(rs4149056), SLCO1B1 388A>G(rs2306283), CYP3A4 1*B(rs2740574), CYP3A4 1*G(rs2242480) and CYP3A5*3(rs776746) using fluorescence in situ hybridization technology. The genotype frequencies of wild-type homozygote, mutant heterozygote and mutant homozygote were 62.57%(TT), 34.22%(TC) and 3.21%(CC) for SLCOIB1 521T>C, and 8.56%(AA), 33.69%(AG) and 57.75%(GG) for SLCOIBI 388A> G, and 62.57%(CC), 34.22%(CT) and 3.21%(TT) for CYP3A4 1 G, and 58.29%(GG), 34.76%(GA) and 6.95%(AA) for CYP3A5*3, respectively. Furthermore, each tested genotype of CYP3A4 1B was wild type. Finally, 5 candidates with specific genotype described above were recruited to carry out the clinical pharmacokinetics of AC (n = 5). The validated UHPLC-MS/MS method was implemented in a high-throughput setting, capable of analyzing up to 288 samples per day, and was successfully applied to the pharmacokinetic study of AC based on healthy volunteers with specific genotype. The C-max of AC in human volunteers with the specific genotype was nearly 10 times higher than that previous reported, indicating that genetic polymorphisms of these specific genotypes have significant influence on pharmacokinetics of atorvastatin. (C) 2018 Elsevier B.V. All rights reserved.