A. P. Hall, V. Holloway, J. Scott
Nov 1, 1964
Citations
0
Influential Citations
23
Citations
Journal
Annals of the Rheumatic Diseases
Abstract
4-hydroxypyrazolo (3,4-d) pyrimidine (B.W. 56-158: HPP) is a potent inhibitor of the enzyme xanthine oxidase. It was first used in the treatment of leukaemia to suppress the oxidation of 6-mercaptopurine to the therapeutically inert metabolite 6-thiouric acid, and the observation that it lowered the concentration of uric acid in serum and urine has led to its use in gout (Rundles, Wyngaarden, Hitchings, Elion, and Silberman, 1963; Klinenberg, Goldfinger, Miller, and Seegmiller, 1963). Fig. 1 shows the chemical structure of HPP; it is an isomer of hypoxanthine and it inhibits the oxidation of the oxypurines hypoxanthine and xanthine to uric acid. The oxypurines are more soluble than uric acid and are excreted in the urine.