Photodegradation of dacarbazine irradiated by common lighting sources: An examination of the differences between light-emitting diode (LED) and fluorescent light.

Light-sensitive pharmaceuticals are susceptible to alteration or degradation under ambient light conditions, such as sunlight or artificial lighting, requiring pharmacists and patients to prevent exposure of these drugs to light. However, the transition from fluorescent to light-emitting diode (LED) light has altered the ambient light characteristics within buildings. Dacarbazine, chemically known as 5-(3,3-dimethyl-1-triazen-1-yl)-1H-imidazole-4-carboxamide (DTIC), is a light-sensitive anticancer drug. Its photodegradation product, Diazo-IC (5-diazoimidazole-4-carboxamide) is known to cause vascular pain in patients during infusion. Utilizing UV/Vis spectroscopy, this study examines the photodegradation of DTIC in aqueous solution under fluorescent and light-emitting diode (LED) lighting conditions, which are both prevalent in contemporary buildings. Results indicate that DTIC remained stable when exposed to LED light, with no decomposition observed, whereas photodegradation occurred under fluorescent light. The residual ratio revealed that DTIC remained stable for 240 min under LED illumination, indicating that LED light exposure does not induce DTIC photodegradation. These findings suggest that the ongoing replacement of fluorescent lighting with LED in healthcare settings and patient residences may eliminate vascular pain associated with DTIC photodegradation in the near future.