In vorliegender Arbeit wurde die Stabilität von Flavonoiden in entsprechenden pflanzlichen Drogen unter Langzeitbedingungen bei 25°C/60% rF und Streßbedingungen bei 40°C/75% rF und bei Temperaturen von 70°C - 100 °C untersucht. Anhand von HPLC-Fingerprintanalysen und photometrischen Methoden wurde das Drogenmaterial untersucht. Bei Gerbstoffdrogen erfolgt die Analyitk mittels photometrischer Methoden und Proteinfällungsmethoden, die auf ihre Eignung für Stabilitsprüfungen untersucht und beurteilt werden sollten.

The aim of the presented work was to examine possible changes in the flavonoid pattern of common flavonoid containing herbal drugs during long term and stress testing periods. HPLC fingerprint was utilized to demonstrate the differences in stability of individual flavonoid components. In addition, the total flavonoid content was determined according to pharmacopoeial photometrical method
Drug material was stored according to the ICH-guidelines at 25 °C and 60 % rh (relative humidity) for long term testing over a 24 months period or at 40°C and 75% rh under stress conditions for 6 months. Increased temperatures were chosen to elucidate possible instabilities of selected flavonoids. As an overall result, during long term testing, no significant changes in the flavonoid pattern can be detected. However, some flavonoid containing herbal drugs (e.g. birch leaves), showed a decrease of most flavonoids when stored at high temperatures by an increase in the respective aglycones. Similar results were obtained during storage at 40°C/75% rh. For tannins, different methods were evaluated for their suitabiliy for stress testing. Photometrical methods like hide powder method, vanillin method, BuOH-method and protein precipitation were object of investigation.