Gel color change - Cosmetic Science Talk

Gel color change

edited January 10 in Formulating

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.

Comments

  • 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.
  • I ought to have suggested also that you prepare samples each with one of the ingedients omitted (apart from water, obviously!)
  • @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!
  • That's an awful lot of niacinamide. How did you arrive at that level?
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • edited January 10
    @Bobzchemist according to various studies on hyperpigmentation, that's the % they generally use.
  • 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)
  • edited January 10
    @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.
  • 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.
  • Thanks for letting us know.
  • It is indeed very nice gesture to complete the circle, corroborates the advices and opinions of the participating members. 
  • Thank you @Christopher and @johnb. Today we all got to learn something new :)
Sign In or Register to comment.