The Effect of Artemisinin on the Pharmacokinetics of Cyclophosphamide and Its Metabolite in Mice and Its Potential Mechanisms

ABSTRACT

Cyclophosphamide (CP) is a common alkylating anticancer drug. Artemisinin (ART), an antimalarial agent metabolized by hepatic CYP450s, exhibits promising antitumor activity. This study established a rapid and accurate LC‐MS/MS method for the quantitative analysis of CP and its metabolite in mouse plasma, as well as to apply this method in assessing how ART influences the pharmacokinetics of CP. Given the instability of 4‐OH‐CP, 4‐keto‐CP was selected as a surrogate metabolite for detection. The effect of ART on the mRNA expression and activity of CYP450 enzymes were assessed by RT‐qPCR and substrate cocktail assay. The results indicated that CP and 4‐keto‐CP were linear in the range of 1–2000 and 2–2000 ng/mL, respectively. The accuracy, precision, extraction recovery, stability, and matrix effect of CP and 4‐keto‐CP are complied with the Bioanalytical Method Validation Guidelines. ART significantly reduced the AUC _{0− t} of CP by 26.6%, while increasing CL/F by 1.35‐fold. Concurrently, the AUC _{0− t} and C _max of 4‐keto‐CP increased by 1.42‐ and 1.45‐fold, respectively. Furthermore, ART can markedly upregulate the mRNA expression and activity of CAR/ CYP2B6 . The results showed that pretreatment with ART could induce CP metabolism to its active metabolite. This study provides implications for the rational use of the ART‐CP combination in clinical practice.