Photodegradation of Pharmaceuticals Studied with UV Irradiation and Differential Scanning Calorimetry
Given rapidly increasing concerns about photodegradation of pharmaceuticals, we have applied accurate methods to quantitatively evaluate the drug photostability. The drugs studied were nifedrine, acetylsalicylic acid, acetaminophen, cetirizine, and pantoprazole. UV energy striking a target has been determined by using graphite. Runs were performed by placing each sample in a pan with a quartz lid and exposing it to ultraviolet (UV) light for periods of time ranging from 1 to 120 seconds. Percentage decomposition as a function of time has been determined for each pharmaceutical.