Photostability Testing Guidelines of New Drug Substances

The ICH Q1B guideline is the harmonised effort to standardise photostability testing on new pharmaceutical drug substances and drug products.

All companies developing or manufacturing pharmaceutical drugs, require a robust photostability testing process to ensure product quality and regulatory compliance. Inadequate testing can result in costly delays and lost revenue.

Photostability Guidelines

Testing is carried out on a single batch of material selected. Under some circumstances these studies should be repeated if certain variations and changes are made to the product (e.g. formulation, packaging). Whether studies should be repeated depends on the photostability characteristics determined at the time of initial filing and the type of variation and/or change made.

The guideline primarily addresses the generation of photostability information for submission in Registration Applications for new molecular entities and associated drug products. It does not cover the photostability of drugs after administration (i.e. under conditions of use) and those applications not covered by the Parent Guideline.

A systematic approach to testing is recommended covering, as appropriate, studies such as:

  • Tests on the drug substance
  • Tests on the exposed drug product outside of the immediate pack

and if necessary:

  • Tests on the drug product in the immediate pack

and if necessary:

  • Tests on the drug product in the marketing pack
UV light Graph created at completion of photostability study
UV light graph created at completion of photostability study
Visible light Graph created at completion of photostability study
Visible light graph created at completion of photostability study

 

Procedure

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. For confirmatory studies, samples should be exposed to light providing an overall illumination of not less than 1.2 million lux hours and an integrated near ultraviolet energy of not less than 200 watt hours/square meter.

  • Samples are exposed side-by-side to ensure the specified light exposure
  • Samples are exposed for the appropriate duration of time
  • Monitoring is completed using calibrated radiometers/lux meters
  • Dark controls, if specified (wrapped in Alufoil,) placed alongside the authentic sample to evaluate contribution of thermally induced change.
  • Reports are generated confirming light exposure over time (see image).

How can we assist you with your photostability studies?

Whether performing forced degradation or confirmatory studies, Q1 Scientific can create the appropriate test conditions in accordance with ICH Q1B.

Our fully qualified, temperature and humidity controlled photostability chamber can be used to help you:

  • Understand how light exposure affects your products so you can take action to ensure product quality and regulatory compliance; OR
  • Demonstrate that light exposure does not result in unacceptable changes

Contact us to find out more about how we can help you with your photostability testing.