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

Abstract

Artemisinin-based combination therapy is widely used for the treatment of uncomplicated Plasmodium falciparum malaria, and piperaquine (PQ) is one of important partner drugs. The pharmacokinetics of PQ is characterized by a low clearance and a large volume of distribution; however, metabolism of PQ has not been thoroughly investigated. In this work, the metabolite profiling of PQ in human and rat was studied using liquid chromatography tandem high-resolution LTQ-Orbitrap mass spectrometry (HRMS). The biological samples were pretreated by solid-phase extraction. Data processes were carried out using multiple data-mining techniques in tandem, i.e., isotope pattern filter followed by mass defect filter. A total of six metabolites (M1-M6) were identified for PQ in human (plasma and urine) and rat (plasma, urine and bile). Three reported metabolites were also found in this study, which included N-oxidation (M1, M2) and carboxylic products (M3). The subsequent N-oxidation of M3 resulted in a new metabolite M4 detected in urine and bile samples. A new metabolic pathway N-dealkylation was found for PQ in human and rat, leading to two new metabolites (M5 and M6). This study demonstrated that LC-HRMS(n) in combination with multiple data-mining techniques in tandem can be a valuable analytical strategy for rapid metabolite profiling of drugs. Copyright © 2016 John Wiley & Sons, Ltd.

Metabolism of Piperaquine to Its Antiplasmodial Metabolites and Their Pharmacokinetic Profiles in Healthy Volunteers

“…Previous studies on the structure-activity relationship revealed that the 7-chloro group is essential for the antimalarial activity of the aminoquinoline compounds (14). PQ mainly underwent oxidation in vivo, and several phase I metabolites have been found in humans; these included two N-oxidation metabolites, a carboxylic acid, and two minor hydroxylated metabolites (12,13). The carboxylic acid has been found to be bioactive.…”

“…The absolute oral bioavailability of PQ was approximately 50% in rat (11). Several metabolites of PQ have been found in rat (11) and human (12,13), and these mainly include two N-oxidation products (metabolite M1 with a molecular weight [MW] of 550 and metabolite M2 with an MW of 566; Fig. S1) and a carboxylic acid metabolite (MW, 319).…”

In vitro Metabolic Stability of Drugs and Applications of LC-MS in Metabolite Profiling

“…Phase I and Phase II metabolites are generally having mass defect values of less than 50 mDa relative to that of the structure of the parent drug. MDF has been applied for the identification of drug metabolites in plasma, urine, feces, bile, and in incubates of liver microsomes and hepatocytes [62,92,93]. All the metabolites generated are not structurally similar to the parent drug, some varies slightly (e.g., oxidation), and some show a significant variation (e.g., GSH adduct 68 mDa).…”

Simultaneous determination of piperaquine and its N‐oxidated metabolite in rat plasma using LC‐MS/MS

“…Several metabolites have been found for PQ in rat (Tarning et al , ) and human (Yang et al , ; Tarning et al , ), mainly including two N ‐oxidation products (MW 550, PQ‐M, Figure ; MW 566) and a carboxylic acid (MW 319). Minor hydroxylated and N ‐dealkylation products have also been detected in rat and human (Yang et al , ; Tarning et al , ). The metabolic clearance of PQ is primarily catalyzed by CYP3A4 (Lee et al , ).…”