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Fri Apr 29, 2005 10:50 am  |
I'm having a problem with the water-soluble L-ascorbic acid I'm using to formulate a serum.
It doesn't want to dissolve in cold water, but my understanding is that heat will destroy the properties of the AA.
What shall I do??
Mary Jane |
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Fri Apr 29, 2005 2:08 pm |
| It should dissolve with no problem. Make sure that you are using pure ascorbic acid crystalline & not ascorbic acid in an excipient. Also, make sure that your proportions are correct. What percentage are you trying to make? 10%, 15%, 20% ???? What other ingredients are you adding other than water & what order are you adding them in? |
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Fri Apr 29, 2005 3:42 pm |
| pbsadhaka wrote: |
| It should dissolve with no problem. Make sure that you are using pure ascorbic acid crystalline & not ascorbic acid in an excipient. Also, make sure that your proportions are correct. What percentage are you trying to make? 10%, 15%, 20% ???? What other ingredients are you adding other than water & what order are you adding them in? |
You can use heated warm water, or you can put it in a coffee grinder and grind it to a finer powder. |
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Fri Apr 29, 2005 5:41 pm |
| it wouldn't dissolve might be due to your water already saturated with the crystals... |
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Fri Apr 29, 2005 6:43 pm |
Thanks for the input, but I think I'm going to need more help.
What I'm using is labeled "L-ascorbic acid." I don't know if it is "pure" AA crystalline and not AA in an excipient, because I don't know what those two terms mean, nor do I know how I could tell from the packaging!
I am trying to make a 25% serum, which is the concentration used in the C-Scape Serum that I get from the dermatologist.
Following is my formula, in the order that I add them:
47% distilled water
25% ascorbic acid
25% propylene glycol
1% Vit. E
1% Poly 20
1% cyclomethicoe
Since I am making such a small batch (2 oz.) I'm not worrying about a preservative.
Any other suggestions?
Mary Jane |
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Fri Apr 29, 2005 10:24 pm |
Mary Jane,
An excipient is a filler (like cellulose, or some other type of starch usually) that an active or vitamin is blended into to act as a base. This is commonly done for vitamin powders that are meant to be ingested.
Pure crystalline Ascorbic acid should readily dissolve in water. If it is not, then there may be an excipient that is preventing dissolution.
I looked at your percentages for your formula. They add up to 100%. So that's good. But what is the order you are blending your ingredients in? You must pre-dissolve the ascorbic acid in the deionized water only, before you add your other liquid ingredients.
Also, how are you measuring out these ingredients? You need to be weighing them out by mass. 1g of the Ascorbic acid weighs more that 1g of water. So if you are not measuring them by mass, then your percentages are wrong. It will be more than a 25% concentration. |
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Fri Apr 29, 2005 10:37 pm |
ooops! I see you did give me the order in which you add your ingredients. YEs, add the AA just to the water. Do notuse heated or warmed water. It will immediately start degrading the hydrogen bonds in the AA & start early oxidation. Just put the water & AA in your glass bottle & cap it. Shake it vigorously for a few minutes. Then let it sit for like 10 minutes. Now add your PG & shake again. Shake it every time you add a new ingredient. If you are measuring it by mass, and there is no excipient in your AA, then it should dissolve easily - within a few minutes.
You can tell if there is an excipient in your AA from the packaging. It should say somewhere something like 20,000 U or U/g. (could be any number). What this means is units per gram. |
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Sat Apr 30, 2005 7:48 am |
I am weighing all of my ingredients on an accurate (I hope, cause it sure was expensive!) scale.
The container my AA came in says:
Description: Synthetic, active form of vitamin C as it occurs naturally. Purity 99.4%
Appearance: Fine white powder, ordorless
Solubility: easily soluble in water & alcohol
pH Value: 3 (0.5% solution)
Melting point: 192*C (378*F)
This is not a vitamin capsule, it is from a cosmetics ingredients supplier.
And what is deionized water? I have been using distilled water.
So it appears the product is okay, I guess I'm just being a serum-tard. 
Mary Jane |
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Sat Apr 30, 2005 8:28 am |
Mary Jane,
WOW! You should be good then - sounds like the right ascorbic acid & the scale is a must. I just noticed that yoou are using vitamin E too. (didn't notice last night b/c I was half asleep!) Is it the water soluble form of vitamin E or are you using an emulsifier? You have "Poly 20" listed, is that Polysorbate 20?
You need to blend the fat soluble components (vit E)into the sorbate & then emulsify that with the water & AA mix. Then once that is fully emulsified, you can add your glycol & silicone. What are you using to emulsify? A blender or something? |
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Sat Apr 30, 2005 8:51 am |
Thanks for the mixing tip - I'll try that next time. I'm making such small batches I can't use my stick blender, so I'm just shaking the bottle like crazy!
I think next time I'm going to try heating the water SLIGHTLY before adding the AA.
MJ |
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