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ICH Testing of Pharmaceuticals – Part 1 - Exposure Conditions

ICH Testing of Pharmaceuticals

ICH Q1B Requirements for Photostability Testing

The FDA (American Food & Drug Administration) requires that all new drugs be tested for shelf life by exposing drugs to simulated sunlight. The international ICH guidelines define appropriate light sources and provides test guidelines. The guidelines Q1B state that drugs must be exposed to a minimum of 1.2 million lux hours of visible light and a minimum of 200 W h/m2 UVA light. These tests are also referred to as Confirmatory Studies.

Further, the ICH guidelines request so called Forced Degradation studies. The test objective here is to force the drug substance to degrade to a point that reveals potential structural weaknesses, which can be addressed either by chemical modifications or packaging. Here, the test device may run for longer duration and/or is using the harsher D65 light condition of simulated outdoor sunlight.

SUNTEST (Option 1) Photostability Chambers and the Question About UV Overexposure

What is meant by this statement and more importantly, is it acceptable to use? As a matter of fact, when a SUNTEST achieves the minimum visible light dose, the minimum UV dose will be exceeded by a factor of approximately 2.4.

Since the ICH guidelines have only defined minimum values for both the Ultraviolet (no less than 200 W h/m2) and the Visible (no less than 1.2 million lux hours), it is perfectly acceptable to expose specimens to the longest exposure of the two. Most Atlas clients using this method typically apply at least 2-3x the minimum exposure requirements, while some may test up to 5x or even 10x. However, if “overexposure” is a concern of yours, simply begin your test with two replicate samples, pulling one replicate from the test when it has reached the UV minimum exposure. The remaining replicate can then be exposed until the minimum visible light dose is achieved.

Test Duration Inside SUNTEST

The two biggest benefits of a SUNTEST are great speed of testing and superior reliability of the solar simulation compared to Option 2 type photostability chambers.

Atlas Blog Posting ICH Suntest

More Information

Download a free Application Guide on Photostability of Pharmaceuticals.

Click here to learn more about SUNTEST instruments.