Implications of in-use photostability: proposed guidance for photostability testing and labeling to support the administration of photosensitive pharmaceutical products, part 1: drug products administered by injection.

Basic guidance on the photostability testing of pharmaceuticals, designed to cover manufacturing and storage over shelf life, has long been established within ICH Q1(ICH,B(10) , but the guideline does not cover the photostability of drugs during or after administration (i.e., under conditions of use). To date, there has been a paucity of guidance covering the additional testing that would be of value during the clinical preparation and use of products. This commentary suggests a systematic approach, based on realistic "worst case" photoexposure scenarios and the existing ICH Option 1 and 2 light sources, to provide valuable data to pharmaceutical manufacturers and compounding pharmacists for the safe and effective use of photosensitive injection products.