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What am I doing wrong? Moisturiser splitting/creaming
Hi all,
First - please be gentle. Long time biochemist, first time cosmetic chemist.
I have created a moisturiser for skin whitening but following centrifugation (4,000 rpm; 10 min), there is a clear splitting with creaming on the top with a clear liquid. I am not sure what I am doing wrong and would really great appreciate the experience of the forum here.
My formulation is below:
I add a liquid (sulfurophane) at the end as the high temperatures during the emulsification process will destroy this natural product.
I also noticed there was a tendency for this moisturiser to clump when it storage (~1 month).
I feel my emulsifiers and stabilisers are off but not sure the best approach moving forward.
Many thanks in advance for advice/help
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12 Replies
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I saw a gelling agent…. GMS, and a fatty alcohol and a thickener…(stearic).
I wouldn’t expect that to hold much together. Stearic does not emulsify until it is converted to a stearate soap at high pH. (I missed the part about pH?) Were you counting on that?
How are competitive benchmarks held together?
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This reply was modified 1 month, 3 weeks ago by Graillotion.
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The final pH of the product was 6.25. Is there something else I can add? In hindsight, I am not sure Inulin Lauryl Carbamate is doing much at all…
Also, sulfurophane is a liquid which i had after the emulsification as it’s heat sensitive. Is it possible that is what’s splitting here?
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This reply was modified 1 month, 3 weeks ago by
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What is NACL doing there?
As your batch size is too small, i think it is just air that has been mixed during homogenization coming out.
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NaCl was to thicken the problem but I dont thinkt it’s working here.
I thought that initially too, regarding the air bubbles. But I can see liquid on top so it’s clear to me the bubbles on top arent just from trapped air but actually splitting of a failed emulsion.
Do you have any ideas on what I could do here?
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I would get rid of NaCl. While I like Inulin Lauryl Carbamate, it is not going to add anything to a thick product as it provides no thickening so I would get rid of that also. I would also add both liquid preservatives post emulsification and also after the pH has been adjusted. I would start by swapping the Stearic Acid and GMS % around, although I expect that will be too much Stearic acid. Perhaps Stearic around 5% and maybe 1% of a non ionic emulsifier of your choice (but not ILC). Once you have emulsified the oil and water you will need to adjust the pH up, with whatever you use (NaOH or something similarly basic). You are going to want the final pH around 7 +/-0.5.
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Thank you! I will test this out and report back!
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For me, it looks like you are trying to make moisturizing cream, but, it started to separate
In a lab batch, you may try: Caprylic Capric triglyceride: 5 - 7 %, Glyceryl Stearate: 1.5 - 2%, Cetyl Alcohol 3%, Cetearyl Alcohol 6%. Both Propylene glycol and pentylene glycol are solvents and solubilizers. If you add both of them in the concentrations you mentioned in the formula, that may break the emulsion. You may only add Propylene glycol 5% and HEC (Hydroxyethylcellulose) 1.5%. You may add Sodium PCA 5% after emulsification and cooling down. It is natural moisturizer factor in our skin. It can bring good moisturization
Try to make you formulas by % and weight units (g). You don’t need to have the volume units in the formula
Your emulsification technique is very important. It may determine the stability of the product.
Sometimes, High Shear Mixer is not enough. You may need to use Homogenizer, also
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Thank you for your advice. I have reformulated with this in mind especially reducing the glycols to 5%.
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I believe many of the ingredients in your formula are not necessary.
Imorganic salts (like NaCl) can actually increase viscosity in some emulsions, but for now, I’d skip it.
For hyperpigmentation in your formula, niacinamide is one of the few that have some solid studies behind, and perhaps tranexamic acid.
Glycols in high amounts would for sure impair your emulsion. I’d add not more than 4% of combined gllycols.
Now, you only have Stearic acid as your sole emulsifier, and not at a pH in which it’s all neutralized. If you don’t want to have a higher pH, then switch emulsifiers. You can use Arlacel 165 (or similar) at 4-5%, remove your Glyceryl stearate and increase your fatty alcohol also around 4%.
I never liked to use HEC in emulsions, but if you want a starch, use Hydroxypropyl starch phosphate, which will also help stabilize the emulsion.
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Great suggestions. I have now reduced my glycols to 5% total. Fingers crossed.
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why removing GMS ?
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It already comes in Arlacel 165.
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