title: Formation of the accumulative human metabolite and human-specific glutathione conjugate of diclofenac in TK-NOG chimeric mice with humanized livers.
abstract: 3'-Hydroxy-4'-methoxydiclofenac (VI) is a human-specific metabolite known to accumulate in the plasma of patients after repeated administration of diclofenac sodium. Diclofenac also produces glutathione-conjugated metabolites, some of which are human-specific. In the present study, we investigated whether these metabolites could be generated in humanized chimeric mice produced from TK-NOG mice. After a single oral administration of diclofenac to humanized mice, the unchanged drug in plasma peaked at 0.25 hour and then declined with a half-life (t1/2) of 2.4 hours. 4'-Hydroxydiclofenac (II) and 3'-hydroxydiclofenac also peaked at 0.25 hour and were undetectable within 24 hours. However, VI peaked at 8 hours and declined with a t1/2 of 13 hours. When diclofenac was given once per day, peak and trough levels of VI reached plateau within 3 days. Studies with administration of II suggested VI was generated via II as an intermediate. Among six reported glutathione-conjugated metabolites of diclofenac, M1 (5-hydroxy-4-(glutathion-S-yl)diclofenac) to M6 (2'-(glutathion-S-yl)monoclofenac), we found three dichlorinated conjugates [M1, M2 (4'-hydroxy-3'-(glutathion-S-yl)diclofenac), and M3 (5-hydroxy-6-(glutathion-S-yl)diclofenac)], and a single monochlorinated conjugate [M4 (2'-hydroxy-3'-(glutathion-S-yl)monoclofenac) or M5 (4'-hydroxy-2'-(glutathion-S-yl)monoclofenac)], in the bile of humanized chimeric mice. M4 and M5 are positional isomers and have been previously reported as human-specific in vitro metabolites likely generated via arene oxide and quinone imine-type intermediates, respectively. The biliary monochlorinated metabolite exhibited the same mass spectrum as those of M4 and M5, and we discuss whether this conjugate corresponded to M4 or M5. Overall, humanized TK-NOG chimeric mice were considered to be a functional tool for the study of drug metabolism of diclofenac in humans.
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.) hidetaka.kamimura@sekisui.com.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Kamimura
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.).
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ito
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.).
authors.forename: Kohei
authors.initials: K
authors.lastname: Nozawa
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.).
authors.forename: Shota
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.).
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Chijiwa
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.).
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Nagatsuka
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.).
authors.forename: Miyuki
authors.initials: M
authors.lastname: Kuronuma
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.).
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Ohnishi
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.).
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suemizu
authors.affiliation: ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Tokyo, Japan (H.K., S.I., K.N., S.Nak., H.C., S.Nag., S.Ni); and Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan (M.K., Y.O., H.S.).
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Ninomiya
mesh_terms: D000818:Animals; D001646:Bile / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D002678:Chimera / Q000378:metabolism*; D004008:Diclofenac / Q000031:analogs & derivatives / Q000378:metabolism*; D005260:Female; D005978:Glutathione / Q000378:metabolism*; D006207:Half-Life; D006801:Humans; D008099:Liver / Q000378:metabolism*; D051379:Mice
chemical_list: C058953:3'-hydroxy-4'-methoxydiclofenac; D004008:Diclofenac; D005978:Glutathione