Home Cosmetic Science Talk Formulating General Stability Test Questions: do you test for UV exposure?

  • Stability Test Questions: do you test for UV exposure?

    Posted by AVisotsky on April 16, 2019 at 12:53 am

    Hello, dear wizards of formulating chemistry. Question: if you are testing for stability, besides temperature, do you normally test for light exposure? Also, when a product says “keep in a cool, dry place” does it mean their stability test was different? And, finally, what are the circumstances for PET? It lasts for a month, so do they keep it warm and cozy or just room temp? Thank you!

    AVisotsky replied 4 years, 11 months ago 6 Members · 8 Replies
  • 8 Replies
  • Max

    Member
    April 16, 2019 at 5:48 am

    Hello, from my very limited experience:
    UV is not required as many cosmetics are sold in none transparent bottles. Now I tested some producs under UV, plain sun…. not always glorious! EDTA, BHA… are often the solution.
    Keep in cool…. refers only to the way the customer should ideally store the product. Stabilities are often conducted at 30 and 40 degrees with… I think 65 and 75% humility.
    For the PET, we get this done outside at the moment, but looking at the test, you would think that 30 degrees should be an obvious temperature. 

  • AVisotsky

    Member
    April 16, 2019 at 6:32 pm

    Thanks @max :)

  • oldperry

    Member
    April 16, 2019 at 7:28 pm

    We always tested for UV exposure, even in opaque bottles. It was more of a safety check but on a couple occasions the plastic reacted with the fragrance or the fragrance leached into to bottle. Mostly, there were only problems with UV when the package was a glass jar.

  • ozgirl

    Member
    April 17, 2019 at 9:59 pm

    We do a basic UV stability test by putting the sample on the window sill. If your product contains a dye this is important because many dyes are not UV stable.

  • AVisotsky

    Member
    April 17, 2019 at 11:53 pm

    Thank you!

  • chemicalmatt

    Member
    April 22, 2019 at 8:52 pm

    Better yet, AV, make your own “black box” UV stability chamber. Get the black-light bulb from an aquarium supply store, some simple hardware and mildly crafty wood-work, paint, and voila! A light stability chamber. I do recommend testing certain products for this too: especially ones with CI colorants, botanical extracts, terpenols, etc. Not uncommon to see discoloration after a few days in the box.

  • sven

    Member
    April 22, 2019 at 9:41 pm

    @chemicalmatt interesting concept 

  • AVisotsky

    Member
    April 24, 2019 at 1:39 am

    Awesome, thanks for the idea, I’ll add it to the list of instruments to build for the lab :)

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