Oxidation of celecoxib by polymorphic cytochrome P450 2C9 and alcohol dehydrogenase.

摘要: Aims Celecoxib is a novel selective cyclooxygenase-2 inhibitor, which subject to extensive hepatic metabolism. The aims of the present in vitro investigation were 1) compare rate celecoxib hydroxylation by different genetic variants cytochrome P450 2C9 (CYP2C9), and 2) identify enzyme(s) involved formation major metabolite carboxycelecoxib. Methods Hydroxycelecoxib was studied human liver microsomes from 35 genotyped livers, as well yeast with recombinant expression variants. Carboxycelecoxib incubated absence or presence cytosol. metabolites identified quantified h.p.l.c. In addition, hydroxycelecoxib oxidation alcohol dehydrogenase (ADH1–3) analysed spectrophotometric monitoring NADH generation NAD+. Results  The  intrinsic  clearance  of  celecoxib  hydroxylation  was  significantly  lower for yeast-expressed CYP2C9.3 (0.14 ml min−1 nmol−1 enzyme) compared CYP2C9.1  (0.44 ml min−1 nmol−1 enzyme).  In  human  liver  microsomes,  a  signifi­cant 2-fold decrease evident CYP2C9*1/*3 samples CYP2C9*1/*1 samples. There also marked reduction (up 5.3 times) sample CYP2C9*3/*3. However, CYP2C9*2 did not differ significantly CYP2C9*1 any systems studied. Inhibition experiments sulphaphenazole (SPZ) triacetyloleandomycin indicated that mainly dependent on CYP2C9 CYP3A4. further carboxycelecoxib completely cytosol NAD+. Additional showed ADH1 ADH2 catalysed this reaction apparent Km values 42 µm 10 µm, respectively, whereas ADH3 no activity. Conclusions results confirm enzyme indicate CYP2C9*3 allelic variant associated markedly slower Furthermore, it shown first time cytosolic dehydrogenase, presumably and/or ADH2.