Photostability of pharmaceuticals

RSSL has boosted its service offering in stability testing with the addition of a new cabinet for conducting photostability studies. The new cabinet will enable RSSL to offer a faster and more complete service to customers, complementing the existing suite of controlled storage cabinets at RSSL.

Light testing is an integral part of the stress testing required by the ICH Harmonised Tripartite Guideline covering the Stability Testing of New Drug Substances and Products (ICH Q1B). Two options for testing are given in ICH Q1B, with option II being preferred by most customers. Here the sample is exposed to light from two sources: a cool white fluorescent lamp and a near ultraviolet lamp, with results being expressed in terms of exposure in lux hours and watt hours per square metre.

The cabinet installed at RSSL is validated for optimum homogeneity of both types of light source, ensuring that all samples receive the same radiation doses, and it is temperature and humidity controlled to ensure that all degradation results are attributable to photostability rather than impacts from other variables. It is suitable for forced degradation and confirmatory studies on the drug substance, the fully exposed product, the product in the immediate package and the product in the marketing package as required.

All of stability work (both storage and testing) carried out at RSSL is cGMP compliant, and the new cabinet will allow RSSL to meet the requirements of ICH Q1B option II with a rapid turnaround of approximately five days.