UIP has received a new SUNTEST CPS+ unit. The SUNTEST CPS+ is equipped with a 1100 watt air cooled xenon arc lamp and is used to test photostability according to ICH Q1B guidelines.  The intrinsic photostability characteristics of new drug substances and products should be evaluated to demonstrate that, as appropriate, light exposure does not result in unacceptable change. The International Conference on Harmonization developed recommendations for the photostability of new drug substances and products. Forced degradation studies are also conducted using the SUNTEST CPS+, as a deliberate attempt to cause light degradation of pharmaceutical substances and products. These studies are a valuable tool to elucidate degradation pathways and to determine method specificity.