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hexagonal II phases of sodium stearoyl lactylate at pH below 5. Is it safe to use?
Today i wanted to make a blend sodium sodium stearoyl lactylate 2%
Glyceryl stearate 2%Water 94%To see how much would be the viscosity.At first it was water thin after cool down. When i reduced the pH to 4 the viscosity directly increased to a viscous lotion like. When increased the pH back to 5.5 it became water thin again. When i searched google about it i found thatWhen SSL is dispersed in water at a pH below 5, it forms hexagonal II phases above its Krafft point (approx. 45 °C) At a higher pH, the fatty acids are ionised and lamellar phases form at a temperature of 45–85 °C.My questions are1. What is hexagonal II phases and lamellar phases?2. is it safe to use SSL in hexagonal II phases? -
9 Replies
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@PhilGeis @Perry
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Read a book about emulsions or just use google, plenty of good explanations available there
.Using different phases is safe unless you had to increase concentration and or temperature to get there (I guess it wouldn’t be safe to use a phase which only formed at 90% SSL at 90°C LoL). Some of these phases are simply more appealing, more practical, and/or more stable than others. -
@Pharma thanks
I asked about safety of it because i was wondering if it is such effective emulsifier and thickener (thick cream with 2% SSL without any other thickener) at low pH, and very good price, why everyone is not using it? -
I don’t like it too much because it tends to make creams soaping
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@Pharma i also use dimethicone 5cst.
Zero soaping at 3% SSL???? -
Correct. Silicones do the trick if you are willing to use silicones. Me, I have a few silicones in stock but I try to get my way around them knowingly missing out on a great deal of astonishingly feeling formulations which can only be obtained with the aid of silicones.IMHO people willing to use silicones might not be too much into the sustainable/green way of life and hence won’t use SSL because there are more draft formulations available without it than with it and the latter tend to use sustainable/green ingredients with all their possible disadvantages a silicone person would not dare risking.
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@Pharma for me the most important factors about emulsifier is 1. working pH range, 2. ease of use, 3. cost per product and 4. skin feel.
I currently use Polyglyceryl 6 distearate. It works well at pH 4 and above. Only one % emulsifier is enough. No co emulsifier needed. Can make low viscosity and high viscosity emulsion by adding fatty alcohol.
I saw SSL is 1/3 the price of it so i thought i check it if i can replace it to reduce the price more.
What emulsifier do you suggest which is better in above 4 aspects?
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SSL would be a great partner for polyglyceryl esters. Maybe substitute 1/5 or so with it? Also, SSL works great in conjunction with fatty alcohols -> triple combinations (or such also including glyceryl monoesters) are frequently used to obtain lamellar phases. The job of SSL in there is mostly that of an anionic emulsifier which stabilises the formulation (electrostatic repulsion).The question about ‘better emulsifiers’ can not be answered for several reasons (as you should know when reading older posts here on the forum).
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@Pharma thanks
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