White Paper: Effective Photo Stability Testing

Photo stability testing is important in developing and manufacturing a wide range of products for some or all of the following reasons. Outside of the necessary guidelines, unfavorable appearance, recessive or misaligned efficacy, physical changes, chemical changes, and microbiological changes are some the important factors that must be looked at.

Stability testing is very important to establish the integrity that a product has to environmental changes. This involves a variety of different parameters specifically VIS and UV light. The ability to duplicate these parameters will create the benchmark for which subsequent testing is done on the same product of different lots or batches. A key aspect in photo stability is to duplicate the exposure of the light to the product or active ingredient. A major part in duplicating conditions is the ability to check the conditions with an appropriate device that can measure the light exposure.

Light is emitted in 3 dimensions and therefore needs to be measured in 3 dimensions and requires a device that will do so. Currently there are 2 types sensors used to measure light. One is planar and the other is spherical both types are used to measure the spectrum of UV and VIS light.