Cosmetic Science Talk

Cosmetic Science discussion forum. For people who want for formulate cosmetics and get advice from other formulators around the world.
*** Click on one of the three Forum categories below to start a new discussion ***

Home Cosmetic Science Talk Formulating Chlorine removal Cleanser/Shampoo - Ingredients

  • Rafacasti

    Member
    April 6, 2022 at 6:30 pm

    Rafacasti said:
    Also, “Disodium EDTA” is for acidic pH (- 7.0) and “Tetrasodium EDTA” is for alkaline pH (+ 7.0).

    @Rafacasti
    What would happen if you used tetrasodium EDTA in products with an acidic pH?

    I’m asking because we ran out of disodium EDTA for a while and we ended up using tetrasodium for a good amount of batches until we got some more delivered. All the products we formulated at that time were acidic. I was told they were more or less interchangeable. 

    Hello, Adamn! I’m sorry for delay in replying!

    Not too sure about the details, but as @PhilGeis said, it evolves solubility (and other little things)

    - Disodium EDTA

    • Sodium cations: 2 (per molecule)
    • Atoms of hydrogen: 4 (two of them are binded with the sodium cations)
    • Molecular mass: 336.2 g/mol
    • pH: 4-6 (sometimes 7, but never higher)
    • Soluble in: water
    • Structure: C(10)H(14)N(2)Na(2)O(8)

    - Tetrasodium EDTA

    • Sodium cations: 4 (per molecule)
    • Atoms of hydrogen: 4 (all of them are binded with the sodium cations)
    • Molecular mass: 380.1 g/mol
    • pH: 10-11 (sometimes higher or lower, but never lower than 7)
    • Soluble in: water, ethanol (slightly)
    • Structure: C(10)H(14)N(2)Na(4)O(8)
    • Also, presents a higher potential to “sequestrate” metal ions

    Both of them are subproducts of EDTA synthesis, used as chelating agents (and sometimes as preservatives, if I’m not wrong)… I heard once that Tetrasodium EDTA is more irritating and presents ecotoxicity in some way, but I’m not sure about that.

    Anyway, I have no examples of incompatibilities between ingredients and these two forms of EDTA, but I think it would make little to no difference in your formulations (as I supposed you’re using low concentrations)… At least in my country (Brazil) I saw Tetrasodium EDTA far fewer times when compared to Disodium EDTA (most of the cases with Tetrasodium had both)

    Sorry if this wasn’t the answer you wanted, but it’s all I could find and remembered. Hope it helps in some way! (:

  • ketchito

    Member
    April 16, 2022 at 10:01 pm

    Hi,

    I was just reading a magazine, and I found this very interesting comment from Dr. Lochhead.

    Reference: https://www.rodpub.com/email/hap/Whitepapers/eBook/2/evonik_eBook.pdf

  • PhilGeis

    Member
    April 17, 2022 at 11:26 am

    Lochhead is a well-recognized hair expert

  • Lab

    Scientist
    April 18, 2022 at 11:59 am

    ketchito said:

    Hi,

    I was just reading a magazine, and I found this very interesting comment from Dr. Lochhead.

    Reference: https://www.rodpub.com/email/hap/Whitepapers/eBook/2/evonik_eBook.pdf

    Thank you @ketchito!

    I looked through the references and found the following patent linked to this comment: https://patentimages.storage.googleapis.com/73/e4/b9/a05e8b915c7d79/US9642787.pdf

    I admit that I’m particularly skeptical about patents because I don’t really understand if there’s really a backing for all of them (even though this one in particular is from The Procter & Gamble Company)… but as @PhilGeis said Dr. Lochhead is an expert on the subject, I tend to believe more

    Thank you guys (:

Page 2 of 2