Disclaimer: I am formulating for personal use only===================================
What is the best method for solubilizing SA ? And how do I overcome instant recrystalization as I add the water?
example: for a 2% SA gel, I used:
- 2% SA
- 8% propylene glycol
- 2% ethoxydiglycol
I do not have my notebook here, but I separatelly made a gel with either 0.5% or 1% sclerotium gum, as I wanted to add 1% vitamin E to the mix (I pre-made a 50%-50% mix of dl-alpha tocopheryl acetate and d-mixed tocopherols). I also remember using 1% or 2% panthenol.
Process:
- weigh SA
- add PG
- add EDG
- mix well until a clear solution is formed (I mixed with no heat and the mixture was clear after a few minutes mixing
- slightly heat the water and mix sclerotium gum until the gel forms
- pour the gel on top of the SA + Solvents blend.
What do I get? That is right - SA crystals. They go away as I heat the mixture and come back as it cools down.
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1. I have asked around and I have received this advice: I should use Na citrate as a buffer (I was going to use NaOH to raise the pH to 3.5-3.8). I was under the impression that I should do that before adding the water , to raise the pH to a 3.8 and later, if needed, to bring it down with lactic acid. I just got my hands on some na citrate so I may try this, but it is very difficult to measure with great accuracy, when you make a 50g or 100g batch! So, if you were me, how would you use the Na citrate and when in the process? if I am to add it to the SA+solvents mix, I will not be able to measure the pH , so I wonder: how much should I use ?
2. after seeing the crystals forming, and as I has some PG leftovers in my bottle, I decided to add some more to the mix (I did not weigh it though). And I also added some PS20 (1-2% in the end, as while mixing and heating water eventually evaporated itself from my beaker). It looked like my gel was finally crystals free, so I decided to put it in my airless opaque container and use it. After a week or so I noticed tiny crystals of SA in the gel. SO it really needs further investigation of the formula

. But the question is: is it still safe to use, or the SA crystals will be ineffective when present on skin?
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edited as I can't spell today!
Comments
Otherwice, BG and PG would be safe too. I can even say ( don't beat me
And the last suggestion: Are you sure your skin is "oily", or it's a kind of Hyperhydrosis? In this case you may want to use other actives than SA.
If you significant;y increase PG and decrease water it will help.
Add 1% sodium citrate to water first and mix till dissolved.
Sal acid will go into PEG-400 if you can use that.
The other thing you can do is raise the pH up till the salicylic dissolves. Not sure what pH it will end up being and not sure if this does anything to the salicylic but it will help dissolve it.