CYP450 Metabolism of a Semisynthetic Naphthoquinone, an Anticancer Drug Candidate, by Human Liver Microsomes

Abstract

CNFD (6b,7-dihydro-5H-cyclopenta[b]naphtho[2,1-d]furan-5,6(9aH)-dione) is a semisynthetic naphthoquinone derived from lawsone that has cytotoxic action in different tumor lines and anticancer activity in vivo. Therefore, this molecule is a relevant candidate for drug development, but there is still no information on its human metabolism and systemic elimination. This study aimed to investigate the in vitro metabolism of this naphthoquinone by human liver microsomes. Initially, in order to determine the in vitro enzymatic kinetic parameters, a high performance liquid chromatography (HPLC) method to quantify the CNFD was developed and validated. In addition, the enzymatic kinetic data, the predicted pharmacokinetic in vivo parameters and the phenotyping study were presented. The main metabolism sites and metabolites have been suggested in silico. The developed HPLC method was linear, reproducible, selective, accurate, and stable. The enzymatic kinetic parameters revealed a sigmoidal profile. In vitro to in vivo extrapolation hepatic metabolic clearance was 10.39 mL min-1 kg-1 protein and the liver extraction rate was 51%. The clearance in vivo associated with a hepatic extraction ratio indicates that the hepatic metabolism is the main route of elimination. Although all cytochrome P450 enzymes evaluated metabolized CNFD, CYP2C9 and CYP3A4 showed higher metabolic capacity. For the first time, metabolism studies of CNFD were demonstrated.