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.
- 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.
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?
edited as I can't spell today!