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Dissolving salicylic acid in ethanol faster & easier for jessner peel
I am making modified jessner peel of this formula
Salicylic acid 14%
Lactic acid 14%
Citric acid 8%
I have ethanol 70%
I have made two samples
1. 50g size
I added salicylic acid to ethanol in RT, mixed for 20 minutes with spoon but SA didn’t dissolve completely, then added lactic acid, then added citric acid. 3g ethanol had evaporated so i added 3g more ethanol and mixed for 10 minutes. . During mixing some SA was sticking and solidified on the walls of the pot in which i was mixing them. At the end there was some undissolved solids but i bottled it. When i saw it next day, it was completely dissolved and uniform.
2. 100g size
Next day i made another batch. Added all the ingredients in a 120ml bottle and shaked for 5 minutes once in each hour. But it didn’t dissolve completely at the end of the day.
Next day there wasn’t any undissolved solids but something string floating as of the picture. I continued shaking bottle for 5 minutes each hour but this thing didn’t dissolve.
My question is
1. Can we use high shear homogenizer to dissolve salicylic acid in ethanol? I red somewhere that it created heat and isn’t suitable specially for large batches.
2. Dissolving SA in ethanol, some ethanol evaporates during mixing, what is the best thing we should do about it? Specially in lage batches.
3. What is your best method to dissolve SA in ethanol or reduce the time of dissolving?
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10 Replies
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The Jessner and Modified Jessner products are made with 95% Ethanol. That is a factor as well.
“Jessner’s Solution has been used for over 100 years as a therapeutic agent to treat hyperkeratotic epidermal lesions. This superficial peeling agent constitutes a mixture of salicylic acid, resorcinol, and lactic acid in 95% ethanol.” (Dr. James Dolezal, Delasco)
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That is a good point.
I will try but unfortunately it is difficult to find 95% ethanol here.
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It won’t work with 70% ETOH. I can tell you that from personal experience.
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Will it crystalize later or it doesn’t dissolve properly at first at 70% ethanol?
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It will crystalize eventually. Also, the lower ethanol content - the lower penetration (but not sure if it is important for ethanol over 60% content)
You can check solubility of SA in ethanol-water solution of different proportions in study called “Solubility prediction of salicylic acid in water-ethanol-propylene glycol mixtures using the Jouyban-Acree model. (see attached image).
As you can see water presence decreases the solubility dramatically.
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I couldn’t understand this chart. Can you explain it that what is what in this chart?
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The first column is a ratio of water to alcohol:
1 - 100% water, 0% ethanol
0.7 - 70% eater, 30% ethanol
…
0.3 - 30% water, 70% ethanol <- your solution.
The second column is solubility per liter. According to the chart it is 191.28 g in 1 liter of 30% water, 70% ethanol solution. Or 19,13g + 100ml solution. Since your solution is not 100% pure ethanol-water mixture and SA also counts in your formula, it seems 14% is too high
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Thank for explaining
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It will recrystallize fairly quickly. It would predictably fail stability each time.
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