Rate constants for reaction of hydroxyl radicals with sulfapyridine and aminosalicylic acids

Article abstract of DOI:10.1248/cpb.44.163

Sulfasalazine, an anti-inflammatory drug, is metabolized to sulfapyridine and 5-aminosalicylic acid (5-ASA) which is therapeutically active. In the inflammation, active oxygen species have been suggested to play an important role. Among various active oxygen species, hydroxyl radical is known to be the most active radical. To elucidate the reactivity of sulfapyridine, 5- ASA, 4-ASA and 3-ASA with hydroxyl radicals, the rate constants were determined measuring the fluorescence of hydroxybenzoates induced by radiolysis hydroxylation of benzoate. The constant for 5-ASA, strongly fluorescent but insoluble in ether, was measured after ether extraction of hydroxybenzoates under acidic condition. For the other compounds, the rate constants were determined using a method which separates hydroxybenzoates by HPLC after the ether extraction, since the three compounds moved to the ether layer and interfered with the fluorescence of the hydroxybenzoates induced. Four rate constants were obtained in the range of 6.4-7.0 x 10⁹ M^-1 s^{- 1}, showing that they similarly scavenge hydroxyl radicals in vitro.

Full text of DOI:10.1248/cpb.44.163

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service