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Stability of a cream with an organic acid
Hello all,
In the past I posted a discussion about an issue I had with a fizzy emulsion. I was noticed that combining an organic acid (Glyoxylic Acid) with a cationic emulsifier basically causes a bath bomb. With that in mind, I replaced the cationic emulsifier with Lonzest MSA (Glyceryl Stearate and PEG-100 Stearate) and since then everything was good for a short period of time.
later on, I adjusted the product by combining different types of hair conditioning agents including PQ-10 (0.5%), Quaternium 91(1-3%), Behentrimonium Chloride (1-3%), Cetyl Esters (1-3%), Stearamidopropyl Dimethylamine (0.2-1%), and more natural oils. Also, the formulation contains EDTA 0.2% and BHT 0.3%. The Acid value is 35-40% (solution).
**The formulation doesn’t contain Cetyl or Stearyl Alcohol**
pH: 1.5-2.0.After some time, we can see a separation, and some of the samples became a bit fizzy. Important to mention that those samples were stored in a cool place during the period. In addition, the samples was releasing air when opening the cap.
Is there anything we are doing wrong with this formulation? Perhaps our stability system is not suitable with this Acid combination?
your professional opinions would be greatly appreciated.
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10 Replies
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have a think about this:what single molecular property do PQ-10, quaternium-91, behentrimonium chloride and stearamidopropyl dimethylamine all have in common at pH 1.5-2.0? -
Well, the first question is: Why are you including the acid to begin with? I am assuming this is a hair straightening treatment?
Second question: pH 1.5 - 2.0 for a hair care product?
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Mark I have a product in my lab given by a customer and which is a hair straightener formula. He said it is from Brazil and the straightening effect remains for 3-6 months. I was told to develop it, checked the pH. It was below 1 and I excused myself.
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LOL! … Life Lesson #4: Some peoples is crazy
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@Chemist77 at that pH it could double as a toilet cleaner
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Bill very well said, explained the same to the customer. Just needed to add some Acusol 882 from our portfolio ?
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So….with that in mind
Is there any efficient way to stabilize this formula if it contains only Cetrimonium Chloride? Around 2-4%.
your responses would be greatly appreciated -
@Lisani - What type of product is it? It’s not clear from the description in this discussion.
But if it is a leave-on cream, you can’t use Cetrimonium Chloride safely at 2-4%. The CIR limit for leave-on application of cetrimonium chloride is 0.25%.
https://www.dropbox.com/s/m6qe9ra97es9hj8/cetrimonium-chloride.pdf?dl=0
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BTMSs contain fatty alcohols, so maybe they are needed for the emulsion to remain stable?
Are you using Cetrimonium chloride or Behentrimonium chloride?
I know for a fact that the former doesn’t work well as an emulsifier unless a fatty alcohol (preferably cetearyl alcohol) is added as coemulsifier. -
Thank you @Perry, I will use this information. Yes it’s a leave on (1 hour max) cream, a hair straightening emulsion.
@Gunther, thanks for your comment, I am using Cetrimonium Chloride, actually I reduced it to 1%, will consider to reduce it again to 0.25% but I’m not sure if it will have a good effect, perhaps will be better to take it off. I do contain cetyl 1% and cetearyl 1.3%.
increasing the glyceryl Stearate or the fatty alcohols tends to build too much viscosity..
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