Home Cosmetic Science Talk Formulating Gel color change

  • Gel color change

    Posted by Christopher on January 6, 2017 at 11:50 pm

    About 2
    months ago, I decided to try my hand at a simple gel recipe for personal use,
    which for a short while seemed like a success. The product initially looked
    exactly like I imagined which was a transparent gel. I stored it in two
    different packages, a 50
    ml airless pump
    and a 5
    ml plastic jar
    and all seemed well. However, after a few weeks, maybe 2, I
    started to notice a slight color change. The product in the jar suddenly had an
    orange tint to it while the product in the airless pump did not. Today the
    color change is even worse; the gel in the jar has completely solidified and
    the tint has turned into a burnt orange color. The gel in the pump is also
    darkening as well at this point. Does anyone have an idea of what might be
    happening? My main theory is that it’s oxidation but I’m not quite sure. I even
    included disodium EDTA in the formula to combat just that but maybe it’s
    present at a too low concentration. If it is oxidation which of the ingredients
    is most likely to be the culprit?

    FORMULA:
    Water 88.9 %

    Hydroxyethyl cellulose 1 %

    Niacinamide 4 %
    n-acetyl glucosamine 2 %
    disodium EDTA 0,1 %

    glycerin 3 %
    EUXYL PE 9010 (phenoxyethanol and ethylhexylglycerin) 1 %

    PROCESS: I started
    by heating the water to 70 degrees and added hydroxyethyl cellulose while
    mixing. After the gel hydrated and cooled to 40 degrees, I added niacinamide,
    n-acetyl glucosamine and disodium EDTA, all of which dissolved nicely. For the
    last step I premixed glycerin and EUXYL PE 9010 (phenoxyethanol and ethylhexylglycerin)
    and then added it to the gel.

    Sunstone replied 8 years ago 6 Members · 11 Replies
  • 11 Replies
  • johnb

    Member
    January 10, 2017 at 8:35 am

    No response yet so, I’ll have a go.

    Not at all sure about the reason for the discoloration but I do know that N-acetylglucosamine is sensitive to pH (as is niacinamide to a lesser extent) so it could be advantageous to check on the pH of your mixture and adjust if necessary.

  • johnb

    Member
    January 10, 2017 at 2:39 pm

    I ought to have suggested also that you prepare samples each with one of the ingedients omitted (apart from water, obviously!)

  • Christopher

    Member
    January 10, 2017 at 5:06 pm

    @johnb thank you, I will perform a knock out test and see if N-acetylglucosamine is the problem. Will also record the pH. Thank you!

  • Bobzchemist

    Member
    January 10, 2017 at 5:11 pm

    That’s an awful lot of niacinamide. How did you arrive at that level?

  • Christopher

    Member
    January 10, 2017 at 5:30 pm

    @Bobzchemist according to various studies on hyperpigmentation, that’s the % they generally use.

  • OldPerry

    Professional Chemist / Formulator
    January 10, 2017 at 5:35 pm

    Were these opaque containers? It could be UV degradation. And you can never discount microbial contamination (although the airless container reduces the possibility that that’s it)

  • Christopher

    Member
    January 10, 2017 at 5:45 pm

    @Perry yeah, the airless container is opaque, but not the plastic jar. Both were stored in a cabinet however and not in any direct light.

  • Christopher

    Member
    March 12, 2017 at 12:08 pm

    Thought I’d come back and give an update:
    It appears @johnb was correct that N-acetylglucosamine was the culprit. After making the formula again without NAG, it is still the same color after being stored for 2 months.

  • johnb

    Member
    March 12, 2017 at 3:25 pm

    Thanks for letting us know.

  • Chemist77

    Member
    March 12, 2017 at 6:39 pm

    It is indeed very nice gesture to complete the circle, corroborates the advices and opinions of the participating members. 

  • Sunstone

    Member
    March 12, 2017 at 7:15 pm

    Thank you @Christopher and @johnb. Today we all got to learn something new :)

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