Home Cosmetic Science Talk Formulating Creating a buffer to a shampoo formulation at pH 5.5

  • Creating a buffer to a shampoo formulation at pH 5.5

    Posted by Poshkay on September 23, 2019 at 10:49 am

    My shampoo formulation is as follows:

    Deionized Water 55.35
    Decyl Glucoside 10
    Cocamidopropyl Betaine 15
    Crodasinic LS30 8
    Crothix 0.25
    EuroNac AMF Ultra 8
    Crodazoquat  2
    Coconut oil 1
    Fragrance 0.2
    Preservative 0.2

    And I would like my shampoo to maintain a stable pH of 5.5. If 2% citric acid can give me a pH 5.5, what corresponding amount of sodium citrate should I put in the formulation to create a buffer effect.

    Also, I am not really satisfied with the foaming. What can I change to improve foaming? Any other general comments about the formulation are welcome.

    belassi replied 4 years, 6 months ago 3 Members · 5 Replies
  • 5 Replies
  • pharma

    Member
    September 23, 2019 at 7:07 pm

    Poshkay said:

    …If 2% citric acid can give me a pH 5.5, what corresponding amount of sodium citrate should I put in the formulation to create a buffer effect.

    Add as much trisodium citrate as you need to obtain a pH of 5.5 to your 2% citric acid solution ;) . Or do you mean a total of 2% citric acid plus citrate and you want to know the ratio of citric acid to trisodium citrate? Buffer tables will help you with that: CLICK ME. Attention, these are often in molar and not grams!

  • Poshkay

    Member
    September 24, 2019 at 9:20 am

    The 2% citric acid will be in shampoo and not in solution…

  • belassi

    Member
    September 24, 2019 at 11:08 pm

    Any other general comments about the formulation are welcome.
    Frankly it’s a terrible formula in some respects including poor choice of surfactants and if you used a good (anionic) one the conditioner would react with it…

  • Poshkay

    Member
    September 25, 2019 at 9:56 am

    Thank you Belassi, wanted a sulphate free formulation. Do you think playing around with the concentrations of the surfactants would make it any better?

  • belassi

    Member
    September 25, 2019 at 9:14 pm

    No, I don’t think so.
    I have heard that the market for ‘sulphate free’ products is now declining. I’ve stopped producing our one such product; customers tried our range and discovered that our non-sulphate-free shampoos performed better and cost less. They stopped buying the sulphate-free one.
    There are plenty of high foaming sulphate free surfactants without having to use glucosides. I based our formula on AKYPO RLM-45. Excellent foam and very high asm % (something like 80 - 90)… I think it was that as the primary, plus CAPB and sodium cocoamphoacetate.
    The downside is that these surfactants do cost a fair bit more than stuff like SLS/SLeS and you also have to use a dedicated thickener. I used Glucamate VLT which is a superb thickener that has preservative and sensorial benefits — but it isn’t cheap.
    An alternative: You could try Plantapon LGC Sorb (Sodium Lauryl Glucose Carboxylate (and) Sodium Lauryl Glucoside) — I found that used at about 30% with around 10% of CAPB it made a really good shampoo, however it still requires use of a proper thickener.

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