文摘
An analytical method for the quantitative measurement of ML-7, a product with possible anti-immune escape activity for feline infectious peritonitis virus (FIPV), in feline plasma was developed and validated. The sample preparation consists of a solid-phase extraction step on an MCX cartridge. ML-7 and ML-9, used as the internal standard for the analysis, were separated on an ACQUITY UPLC? BEH C18 reversed-phase column (1.7 ¦Ìm, 50 mm ¡Á 2.1 mm I.D.), using isocratic elution with acetonitrile and 0.1 % formic acid in water as the mobile phase. Both compounds were subsequently quantified in MRM mode on a Micromass? Quattro Premier? XE triple quadrupole mass spectrometer. The use of a Thermo Scientific? Exactive? orbitrap mass spectrometer made it possible to confirm the proposed fragmentation pattern of both ML-7 and ML-9. A validation study according to EC requirements was carried out, in which the method showed good performance. Linear behaviour was observed in the 1-2500 ng ml?1 range, which is relevant for real sample analysis. Accuracy and precision were within the criteria requested by the EC requirements throughout this concentration range. Extraction recovery of ML-7 was 72 % . Matrix effect for ML-7 was not higher than 8 % . The method was successfully used for the monitoring of ML-7 in feline plasma after intravenous, subcutaneous or oral administration of an ML-7 formulation, for the determination of pharmacokinetic parameters, with a limit of quantification of 1 ng ml?1 and a limit of detection of 0.4 ng ml?1. The proposed method also shows good characteristics for the analysis of ML-7 in plasma of other animal species and human plasma.