PHOTODEGRADATION OF ANTIMYCOTIC DRUGS .4. COMMUNICATION - PHOTODEGRADATION OF FLUCYTOSINE AND GRISEOFULVIN

The antimycotic drug substances flucytosine and griseofulvin are degra ded under the influence of light. A liquid chromatography-mass spectro metry system helped us to elucidate some of the photodegradation pathw ays. 5-Fluorouracil is one of the photodegradation products of flucyto sine in aqueous solution. The photodegradation of griseofulvin in solu tions is mainly influenced by the solvent. The photodegradation produc t deschlorgriseofulvin could be detected in aqueous solution as well a s in ethanolic and methanolic solution. Two photodegradation products found in ethanolic solution could, however, not be detected in methano lic or aqueous solution. Storage instructions of the pharmocopoeias ar e quite surprising. The US and the German pharmacopoeia recommend ligh t protected storage for flucytosine but not for griseofulvin although griseofulvin is photodegraded more rapidly than flucytosine.