In Vitro Phototoxicity Testing Using SUNTEST®
Phototoxicity refers to the toxic response that occurs when a chemical or medical substance is exposed to sunlight, especially to the ultraviolet (UV) portion. This phenomenon is significant as it can lead to serious effects on human skin and other tissues. To ensure the safety of medical products, phototoxicity testing is essential, and SUNTEST is the ideal tool for such tests.
OECD 432 and the SUNTEST
OECD – the international Organisation for Economic Co-operation and Development - provides a standardized method for evaluating the phototoxic potential of chemicals in its guideline OECD 432. It applies the in vitro 3T3 Neutral Red Uptake (NRU) phototoxicity test using laboratory solar simulators like the SUNTEST. Both models, SUNTEST CPS and XLS are ideally suited for such in vitro testing, because both provide realistic solar UV combined with perfect test temperature control at the required level.
Test Conditions and Duration
The OECD 432 guideline for the in vitro 3T3 NRU phototoxicity test using the SUNTEST can be summarized as follows:
SUNTEST CPS / XLS
Optical Daylight filter
Irradiance: 36 W/m2 (300-400 nm)
Test temperature: ~25°C (SunCool chiller)
Test Duration: 25 min
Now, what is the job of the vital dye Neutral Red? This indeed special dye makes it possible to distinguish between viable and dead cells after exposure to sunlight in a SUNTEST. Damaged and dead cells turn red! Undamaged cells remain clear.
The OECD 432 requests radiant exposure of 5 J/cm2 of UV (320-400 nm). This is precisely what is achieved by a 25-minute SUNTEST irradiation under the test conditions mentioned above.
SUNTEST CPS and exemplary test tray for in vitro NRU phototoxicity testing
With SUNTEST, medical and cosmetic research teams can analyse the effects of sun exposure in the laboratory to develop safe medical and skin care products.
More Information
For further information on the practical SUNTEST benchtop instruments we recommend visiting the product section of our website or listening to a recorded seminar about SUNTEST applications.
Additionally, you may browse our technical library or review upcoming educational classes.