PT - JOURNAL ARTICLE AU - Atsushi Fukunari AU - Ken Okamoto AU - Takeshi Nishino AU - Bryan T. Eger AU - Emil F. Pai AU - Miho Kamezawa AU - Ichimaro Yamada AU - Norihisa Kato TI - Y-700 [1-[3-Cyano-4-(2,2-dimethylpropoxy)phenyl]-1<em>H</em>-pyrazole-4-carboxylic Acid]: A Potent Xanthine Oxidoreductase Inhibitor with Hepatic Excretion AID - 10.1124/jpet.104.070433 DP - 2004 Nov 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 519--528 VI - 311 IP - 2 4099 - http://jpet.aspetjournals.org/content/311/2/519.short 4100 - http://jpet.aspetjournals.org/content/311/2/519.full SO - J Pharmacol Exp Ther2004 Nov 01; 311 AB - Y-700 (1-[3-Cyano-4-(2,2-dimethylpropoxy)phenyl]-1H-pyrazole-4-carboxylic acid) is a newly synthesized inhibitor of xanthine oxidoreductase (XOR). Steady-state kinetics with the bovine milk enzyme indicated a mixed type inhibition with Ki and Ki ′ values of 0.6 and 3.2 nM, respectively. Titration experiments showed that Y-700 bound tightly both to the active sulfo-form and to the inactive desulfo-form of the enzyme with Kd values of 0.9 and 2.8 nM, respectively. X-ray crystallographic analysis of the enzyme-inhibitor complex revealed that Y-700 closely interacts with the channel leading to the molybdenum-pterin active site but does not directly coordinate to the molybdenum ion. In oxonate-treated rats, orally administered Y-700 (1–10 mg/kg) dose dependently lowered plasma urate levels. At a dose of 10 mg/kg, the hypouricemic action of Y-700 was more potent and of longer duration than that of 4-hydroxypyrazolo(3,4-d)pyrimidine, whereas its action was approximately equivalent to that of 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-5-thiazolecarboxylic acid, a nonpurine inhibitor of XOR. In normal rats, orally administered Y-700 (0.3–3 mg/kg) dose dependently reduced the urinary excretion of urate and allantoin, accompanied by an increase in the excretion of hypoxanthine and xanthine. Y-700 (1 mg/kg) was absorbed rapidly by the oral route with high bioavailability (84.1%). Y-700 was hardly excreted via the kidneys but was mainly cleared via the liver. These results suggest that Y-700 will be a promising candidate for the treatment of hyperuricemia and other diseases in which XOR may be involved. The American Society for Pharmacology and Experimental Therapeutics