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2% Salicylic Acid solution cloudy?
Hello,
I’ve been trying to make a 2% Salicylic Acid serum (basically copying Paula’s Choice) but my resulting solution was cloudy.
The formula I used was:
10% Salicylic Acid in Propanediol + Propylene Glycol (50/50 mix of both) 20% Sodium Citrate 1% Polysorbate 20 3% Green Tea Extract (liquid) 1.5% Tetrasodium EDTA 0.15% Distilled Water 74.05% Liquid Germall Plus (haven’t added this yet) 0.3% 1. Mix 10% Salicylic Acid in 45% Propanediol and 45% Propylene Glycol
2. Mix Sodium Citrate, Tetrasodium EDTA, Green Tea Extract, Polysorbate 20, and Distilled Water in a separate beaker
3. Add in the 10% Salicylic Acid
After mixing the beakers together, I noticed that the final solution was cloudy. After letting it sit overnight, it didn’t look like the SA was precipitating but it was still cloudy. pic 1 pic 2 (same pictures as below) Oh, and the solution was pH 4.
The rest of my 10% SA stock however was still clear.
A redditor said that they had some experience with polysorbate making their product cloudy. So I did another test: (yes this only adds up to 99.7%. I left 0.3% blank for the Liquid Germall Plus I would’ve added).
6% Salicylic Acid in Propanediol + Propylene Glycol 33.33% Sodium Citrate 1% Distilled Water 64.87% Polysorbate 20 0.5% 1. Mixed Sodium Citrate into the Distilled Water
2. Added in the Salicylic Acid - At this point the solution was still clear, no precipitates
3. Added in the polysorbate 20 - when I mixed this in for a glass stirrer, it turned the solution cloudy. I used a hand mixer for 30 seconds afterwards to thoroughly mix it and it was still cloudy. No SA crystals though.I also mixed a separate beaker without the polysorbate 20:
1. Added the 6% SA directly into water - saw small slivers of precipitate start to form
2. Added in the sodium citrate and put the beaker into a hot water bath for 1-2 min - solution cleared up and no more precipitates remained.Conclusion: looks like the Polysorbate 20 is making my solution cloudy. Not sure 1. If this is a problem 2. How to fix it
If anyone has any advice/experience, it’d be appreciated.
Thank you. -
3 Replies
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@Arcene The main question would be why are you adding PS-20 and at such a high level? I don’t see any oily material, so I’d actually remove it. It you want to have some thickness, there are other ways. The turbidity might be due to the kraft point of your system.
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I think you are simply not adding enough solvent to the system. Increase your glycols to 30% from 20% and that will help. Also, it does not appear that you are applying heat to the system. Paula’s Choice uses Methylpropanediol as the solvent, so you might try switching to this solvent that better solubilizes SA
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What is your final pH?
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