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SOLUBILITIES, MANDELIC ACID
Hi,
I am working on three mandelic acid peelings (30-40 and 50%), pH around 3. The problem I have is that in the 6th month all begin to precipitate. I use ethanol to solubilize it up to 30%. In formula I have 5% of propilenglycol (I am not sure if does it help). I found that the solubility of the mandelic acid in ethanol is 0,16M. I am stuck with the calculation of alcohol I need for 30% of mandelic acid….cause its turn out to be 300% of ethanol so it is impossible.
Could anyone explain me how to calculate the %ethanol I need to solubilize for example 30% of mandelic acid.
I would appreciate as well if you suggest me any tip or cosmetic raw material will help me solubilize mandelic acid.
Thank you in advantage,
Maes
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12 Replies
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181.0 mg/mL in water, from Human Metabolome Database. Seems marginally more soluble than in ethanol, but not so you can get that kind of increase. I don’t see any resolution for your question. -
Thank you Belassi.
The thing is that the sources do not really specificate the exact solubility, I found 0,16M in the open notebook science. But in most sources I read that mandelic acid is partially soluble in water and freely soluble in ethanol. So I am confused because this value (0,16M) it doesn’t fix with freely soluble… isn’t it?.
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Commercial high strength mandelic acid peels tend to use a mixture of water, propanediol, ethanol and glycerin as solvent. Proportions of each are not disclosed.
Note that propanediol means 1,3-propanediol (Zemea) which is not the same as propylene glycol (1,2-propanediol) and has somewhat different solvent properties. You may find that longer chain polyols are even better solvents.
With using multiple solvents, I think the determination of the optimum blend is a matter of trial and error rather than calculation.
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Thank you John, good tips
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Trail and error it is:we finally wound up with a mixture of 1,3 propanediol and pentylene glycol.Using mixed alpha hydroxy acids with which you can go lower and still make an acceptable peel without stinging.
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The thing is that we would like to have 3 peelings to different concentration 30% - 40% and 50%. I saw some brands with even 70% in their label (they don’t put the ingredients).
Some of the peelings I found online have the water before the alcohol in their label so it seems that water solubilize the mandelic better rather than ethanol.
Refering to the other solubilizers, according to your suggestions, 1,3-propanediol is better than propylene glycol. And then, glycerin or pentylene glycol? Where did you get all the information? hahahahha I’ve been searching a lot and it’s maddening! I find nothing! I would appreciate if you know any source of information
Thank you again
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I found the information I offered via Google using the keywords mandelic acid 50%. It took me less than one minute.
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you are lucky as I did the same and I didn’t find such information, most I found use propylene glycol. But thank you again
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Somehow we have missed the main problem which as you initially said was precipitation after six months presumably at ambient RT meaning need for cosolvent with water.For three variants suggest make up 30:70 -50:50 &70/30 propanediol/water and do low temp i.e. 40C to accelerate flaking with control based on your current system.
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Hi!!!
According to my lab testings I would say that:Mandelic is more soluble in alcohol rather than water and better using alcohol+water rather than alcohol alone (being the alcohol the main solvent).
The thing is that I should probably increase the % of propanediol (cosolvent) in formula. Good idea that I didn’t take into account.
Thank you very much
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Hi! I was also having a hard time solubilizing mandelic acid but I discovered just today that TRANSCUTOL CG can completely and easily dissolve mandelic acid in just a minute! ?
Add water to mandelic acid.
Add Transcutol CG (you can start at 0.3%, depending on the amount of your mandelic acid)
and watch how the magic works!I hope this will be helpful to everybody trying to handle mandelic acid.
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