Home Cosmetic Science Talk Formulating Unexpected change of color

  • Unexpected change of color

    Posted by ngarayeva001 on July 10, 2021 at 9:55 pm
    Hello All!
    Could you please help me demystifying colour change of two of my formulas?
    Product 1: gentle face wash for foaming bottle. LOI - SLMI, Sodium Cocoyl Glutamate, Cocamidopropyl Hydroxysultaine, PEG-7 Glyceryl Cocoate, Na2 EDTA, preserved with Germaben II. ASM 9%
    Product 2: gel with tranexamic acid. LOI - tranexamic acid, niacinamide, ethoxydiglycol, sorbitol, isopentyldiol, EDTA, preserved with Germaben II.
    Both products changed colour from crystal clear to pinkish within 24 hours. I have been making that face wash for several years and had not noticed any colour changes before. I made tranexamic acid gel for the first time. 
    The only things in common between these products are EDTA and Germaben II. I checked suppliers info for Germaben, it expires in may 2022.
    pH of the face wash is 6.5-6.7, pH of tranexamic acid gel is 5.8-6. No changes of pH after products changed colours.
    Thank you very much in advance.
    Sami replied 2 years, 10 months ago 4 Members · 6 Replies
  • 6 Replies
  • ngarayeva001

    Member
    July 13, 2021 at 7:58 am

    I tried to increase pH to 10 and decrease to 2 to see if color would change. It didn’t. I also observed germaben in water to see if it would change color. Again it didn’t. I am very puzzled.

  • Raychemist

    Member
    July 13, 2021 at 11:19 am

    Did you use the same production equipment for both formulations? If yes, what are your SOP’s for cleaning of such production equipment?

  • Abdullah

    Member
    July 13, 2021 at 1:25 pm

    Were you making the same product, in same equipment the same way and it didn’t change the color in the past and is changing now? 

    Have you changed the supplier of any ingredient? 

    How much EDTA are you using? 
    Slmi needs a good amount of chelating agent. Try %0.2 and see what happens.

    What material is the equipment and for how much time your face wash is in that equipment? 
    Facewash sometimes change color in metal equipments.

    Are you using any EO or fragrance oil? 

  • ngarayeva001

    Member
    July 15, 2021 at 10:09 pm

    With the face wash, it’s the same product, same equipment, same ingredients that I already used. Re equipment: beaker, stirring magnet and steel spatula. I have been making this exact product for over 2 years on a regular basis and this is the first time it changes colour. I thought it’s a preservative and prepared solution of just preservative in the water (from the same container). Have been observing it for several days and there is no change of colour.

    Re chelator, although citric acid isn’t the best chelator it’s sufficient to make SLMI transparent. I still use 0.1% of Na2 EDTA.

    Regarding tranexamic acid gel, this is the first time I have made it. I wouldn’t be surprised if it changed colour as it’s a new ingredient for me but I have no explanation for the face wash.

  • Abdullah

    Member
    July 16, 2021 at 6:09 am

    This stock of ingredients that you currently have, have you made any facewash with all of them in it without color change?

    If no and some of these raw materials you have purchased recently and use it for first time then the problem may be in that particular batch of that raw material. 

    If yes then maybe the equipments was contaminated with something with color. 

    Have you made this face wash again in another (preferably clean plastic) equipment and saw if the color change or not?

  • Sami

    Member
    July 16, 2021 at 7:40 am

    Hi.. TRY TO REPLACE THE PRESERVATIVE WITH SOMETHING THAT DIDN`T CONTAIN DIAZOLIDINYL UREA. 

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