[Interaction between atorvastatin and voriconazole in rat plasma: a HPLC-MS/MS-based study].

Objective: To develop a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneous determination of atorvastatin and voriconazole in rat plasma and investigate the pharmacokinetics of atorvastatin and the changes in voriconazole concentration in rats after administration.

Methods: Plasma samples were collected from rats after intragastric administration of atorvastatin alone or in combination with voriconazole. The samples were treated with sodium acetate acidification, and atorvastatin and voriconazole in the plasma were extracted using a liquidliquid extraction method with methyl tert-butyl ether as the extractant. The extracts were then separated on a Thermo Hypersil Gold C18 (2.1×100 mm, 1.9 μm) column within 6 min with gradient elution using acetonitrile and water (containing 0.1% formic acid) as the mobile phase; mass spectrometry detection was achieved in selective reaction monitoring (SRM) mode under the positive ion scanning mode of heated electrospray ion source (H-ESI) and using transition mass of m/z 559.2→440.2 for atorvastatin and m/z 350→280 for voriconazole, with m/z370.2→252 for lansoprazole (the internal standard) as the quantitative ion.

Results: The calibration curves were linear within the concentration range of 0.01-100 ng/mL (=0.9957) for atorvastatin and 0.025-100 ng/mL (=0.9966) for voriconazole. The intra-day and inter-day precisions were all less than 13%, and the recovery was between 66.50% and 82.67%; the stability of the plasma samples met the requirements of testing. The AUC of atorvastatin in rat plasma after single and combined administration was 438.78±139.61 and 927.43±204.12 h·μg·L, CLz/F was 23.89±8.14 and 10.43±2.58 L·h·kg, C was 149.62±131.10 and 159.37±36.83 μg/L, t was 5.08±1.63 and (5.58±2.11 h, and T was 0.37±0.14 and 3.60±1.52 h, respectively; AUC, CLZ/F and T of atorvastatin in rat plasma differed significantly between single and combined administration. The HPLC-MS/MS system also allowed simultaneous determination of voriconazole concentration in rat plasma after combined administration.

Conclusions: The HPLC-MS/MS system we established in this study is simple, rapid and sensitive and allows simultaneous determination of atorvastatin and voriconazole in rat plasma. Some pharmacokinetic parameters of atorvastatin are changed in the presence of voriconazole, and their clinical significance needs further investigation.