ABSTRACT
INTRODUCTION Knowledge concerning the degradation behavior of pharma ceuticals under ultraviolet-visible (UV-VIS) photon exposure is of increasing importance. One reason for this is the steady rise in the number of drug substances with known photoinstability and their potential uses as phototherapeutic agents. On the other hand, there are also legal requirements concerning unknown impurities and the structural elucidation of degradation products ( 1 ). Therefore, knowledge of the photolability of a drug substance is not sufficient. There is a strong demand to characterize the photodecomposition products and the photochemical degradation pathways. Furthermore, there are many current publications discussing photon-induced side effects of pharmaceuticals. In this field, there is a need to investigate whether the side effects are due to toxic photodegradation products or due to an invivo reaction, such as a photosensitization.
