IDENTIFICATION OF CHLOROTHIAZIDE AND HYDROCHLOROTHIAZIDE UV-A PHOTOLYTIC DECOMPOSITION PRODUCTS

Methanol solutions of hydrochlorothiazide and chlorothiazide were irra diated with fluorescent UV-A lamps in order to simulate degradation un der normal conditions. The degradation products were identified by com parison to synthetic standards featuring electrospray ionization mass spectroscopy, ultraviolet spectroscopy, and high performance liquid ch romatography. The standards were characterized by high resolution fast atom bombardment MS and H-1 NMR. The photolysis of chlorothiazide res ulted in photodehalogenation products exclusively, while the irradiati on of hydrochlorothiazide primarily yielded photodehalogenation produc ts with significant yields of photodehydrogenation products and minor amounts of thermal hydrolysis products.