Oxonic acid-13C2,15N3 is intended for use as an internal standard for the quantification of oxonic acid (potassium salt) by GC- or LC-MS. Oxonic acid is a uricase inhibitor (IC50 = 0.8 µM) that prevents metabolism and excretion of uric acid.1,2 It also inhibits orotate phosphoribosyltransferase (ORPT), reducing OPRT-mediated phosphorylation of 5-fluorouracil in Yoshida sarcoma cell extracts with an IC50 value of 3.7 µM.3 Oxonic acid (10-50 mg/kg) decreases the severity of gastrointestinal tract injury and the incidence of diarrhea induced by the 5-FU prodrug tegafur and uracil without loss of antitumor activity in a rat Yoshida sarcoma model. It has also been used to induce hyperuricemia in rodents.4 Formulations containing oxonic acid have been used in the treatment of head, neck, lung, pancreatic, gastric, and breast carcinomas.
1.Johnson, W.J., and Chartrand, A.Allantoxanamide: A potent new uricase inhibitor in vivoLife Sci.23(22)2239-2244(1978) 2.Gralla, E.J., and Crelin, E.S.Oxonic acid and fetal development: I. Embryotoxicity in miceToxicology6(3)289-297(1976) 3.Shirasaka, T., Shimamoto, Y., and Fukushima, M.Inhibition by oxonic acid of gastrointestinal toxicity of 5-fluorouracil without loss of its antitumor activity in ratsCancer Res.53(17)4004-4009(1993) 4.Stavric, B., and Nera, E.A.Use of the uricase-inhibited rat as an animal model in toxicologyClin. Toxicol.13(1)47-74(1978)