In vitro metabolism of a new cardioprotective agent, KR-32570, in human liver microsomes.
KR-32570 (5-(2-methoxy-5-chlorophenyl)furan-2-ylcarbonyl)guanidine) is a new reversible Na+/H+ exchanger inhibitor for preventing ischemia-reperfusion injury. This study was performed to identify the metabolic pathway of KR-32570 in human liver microsomes. Human liver microsomal incubation of KR-32570 in the presence of NADPH and UDPGA resulted in the formation of six metabolites, M1-M6. M1 was identified as O-desmethyl-KR-32570, on the basis of liquid chromatography/tandem mass spectrometric (LC/MS/MS) analysis with the synthesized authentic standard. M2 and M3 were suggested to be hydroxy-KR-32570 and hydroxy-O-desmethyl-KR-32570, respectively. M1, M2, and M3 were further metabolized to their glucuronide conjugates, M4, M5, and M6, respectively. In addition, the specific P450 isoforms responsible for KR-32570 oxidation to two major metabolites, O-desmethyl-KR-32570 and hydroxy-KR-32570, were identified using a combination of correlation analysis, chemical inhibition in human liver microsomes and metabolism by expressed recombinant P450 isoforms. The inhibitory potency of KR-32570 on clinically major P450s was investigated in human liver microsomes. The results show that CYP3A4 contributes to the oxidation of KR-32570 to hydroxy-KR-32570, and CYP1A2 play the predominant role in O-demethylation of KR-32570. KR-32570 was found to inhibit moderately the metabolism of CYP2C8 substrates.
Kim
Hyojin
H
Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Korea. dstlkh@inje.ac.kr
Kang
Suil
S
Kim
Hyunmi
H
Yoon
Yune-Jung
YJ
Cha
Eun-Young
EY
Lee
Hye Suk
HS
Kim
Jeong-Han
JH
Yea
Sung Su
SS
Lee
Sang-Seop
SS
Shin
Jae-Gook
JG
Liu
Kwang-Hyeon
KH
D002316:Cardiotonic Agents / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D019388:Cytochrome P-450 CYP1A2 / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006146:Guanidines / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
D002316:Cardiotonic Agents; D006146:Guanidines; C502305:(5-(2-methoxy-5-chloro-5-phenyl)furan-2-ylcarbonyl)guanidine; D003577:Cytochrome P-450 Enzyme System; C504573:CYP1A2 protein, human; C104464:CYP3A protein, human; D019388:Cytochrome P-450 CYP1A2; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human