Metabolite identification of the antimalarial naphthoquine using liquid chromatography–tandem high‐resolution mass spectrometry in combination with multiple data‐mining tools

摘要

Abstract Naphthoquine (NQ) is one of important partner drugs of artemisinin‐based combination therapy (ACT), which is recommended for the treatment of uncomplicated Plasmodium falciparum. NQ shows a high cure rate after a single oral administration. It is absorbed quickly (time to peak concentration 2–4?h) and has a long elimination half‐life (255?h). However, the metabolism of NQ has not been clarified. In this work, the metabolite profiling of NQ was studied in six liver microsomal incubates (human, cynomolgus monkey, beagle dog, mini pig, rat and CD1 mouse), seven recombinant CYP enzymes (1A2, 2B6, 2C8, 2C9, 2C19, 2D6 and 3A4) and rat (plasma, urine, bile and feces) using liquid chromatography tandem high‐resolution LTQ‐Orbitrap mass spectrometry (HRMS n ) in conjunction with online hydrogen/deuterium exchange. The biological samples were pretreated by protein precipitation and solid‐phase extraction. For data processing, multiple data‐mining tools were applied in tandem, i.e. background subtraction and followed by mass defect filter. NQ metabolites were characterized by accurate MS/MS fragmentation characteristics, the hydrogen/deuterium exchange data and c Log P simulation. As a result, five phase I metabolites (M1–M5) of NQ were characterized for the first time. Two metabolic pathways were involved: hydroxylation and N ‐oxidation. This study demonstrates that LC‐HRMS n in combination with multiple data‐mining tools in tandem can be a valuable analytical strategy for rapid metabolite profiling of drugs.