Photostability of dithranol.
The influence of light on the antipsoriatic drug dithranol was investigated. A Suntest CPS with xenon lamp and liquid cooling was used as light source for the test. Solutions of dithranol in different organic solvents and in therapeutical concentrations in excipients for the preparation of topical formulations were tested under defined conditions. The extent and rate of photodegradation was determined and compared with the degradation of light-protected solutions. The drug content in the solutions was measured by HPLC. Degradation products were characterised and identified by diode array technique and HPLC-mass spectrometry coupling. The results showed a strong dependency of the photodegradation on the excipient or solvent used.
Thoma
K
K
Department of Pharmaceutical Technology, Ludwig-Maximilians-University, Munich, Germany. prof.thoma@Irz.uni-muenchen.de
Holzmann
C
C
D000287:Administration, Topical; D000875:Anthralin / Q000737:chemistry* / Q000528:radiation effects; D000893:Anti-Inflammatory Agents / Q000737:chemistry* / Q000528:radiation effects; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D008027:Light; D010777:Photochemistry; D012997:Solvents; D013472:Sunlight; D013997:Time Factors
D000893:Anti-Inflammatory Agents; D012997:Solvents; D000875:Anthralin