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Anyone know what can be used to gel an alcohol (absent water)?
Hi there,
I am working on developing an anhydrous serum which, functionally, consists of just l-ascorbic acid (and potentially other vitamin acids besides it) dissolved in glycerin. I was able to achieve this but the problem of course is that pure glycerin is aesthetically unacceptable to daub onto skin.
Now I have strong reasons to insist on keeping this a water-free formulation, so I cannot just add water and a gelling ingredient (pectin, guar gam, xanthan gum, etc.) to improve the consistency. I need to find a way to gel glycerin (an alcohol) in the absence of water.
Does anyone have any tips? Or other tips for improving the aesthetic feel of this serum so long as they don’t require the addition of water?
Many thanks in advance! -
20 Replies
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Is there such a thing as anhydrous glycerin? At least 0.5% is water if you use the 99.5%
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Yes, so water is an incidental ingredient of the final product as the glycerin is a humectant and will draw some from the environment etc. But I need the water to be practically nonexistent. I have a few reasons for it: 1) The % of acids dissolved in glycerin is relatively high, if we had an aqueous solution, the PH would be low and the product would be irritating to the skin. 2) Also l-ascorbic acid is notoriously unstable in water 3) I would then need to preserve the serum (although if the glycerin % is high enough compared to water, say 50-60% and up, I could get away with no preservative, but that still doesn’t help with stability etc.). So I just need it to be glycerin + some sort of geller / thickener that plays nice with it in the absence of water.
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Maybe you could get away with a dispersion or emulsion in a silicone base? That might give it some heft without the sticky feeling of glycerin. I don’t know if this is feasible because silicone emulsions aren’t my thing, but it could be worth a think. There’s some very nice silicone polymers that could help.
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try hydroxypropyl cellulose
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I see your reasoning but I don’t believe it stands any chance of working.
L-ascorbic acid is therefore relatively soluble in water. It is much less soluble in glycols such as propylene glycol (50 mg/ml) and in alcohols such as ethanol (10 mg/ml in absolute ethanol) and insoluble in glycerin as stated in the prior art. -
Aloe vera gel?
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Bill, I came across a hint towards hydroxypropyl cellulose in another search. Any tips for incorporating it? Ballpark ratios? homogenization procedure? Temperature?
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Belassi, that “prior art” is old old school. There’s new art in the patent world to make it work.
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p.s. Belassi, I came across your comment re: hydrolyzing oat proteins via a tiny bit of lye and then neutralizing with lactic acid. I could hydrolyze colloidal oats by just cranking up the heat. It’s the same phenomenon as your porridge thickening when cooking. The oats self-emulsify.
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em — aloe vera gel contains water.
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@medaura all you need to know can be found in this manufacturer’s brochure
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Thanks Bill but according to their tech sheet it’s insoluble in glycerin. See screenshot
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@em88
Aloe Vera is 99% water -
Yeah, that’s right. My bad. I did not understood the problem correctly.
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to keep it simple hydroxypropyl cellulose is the easy way.
sorry for the long link, what about ussing high molecular weight PEGs, what viscosity so you need to achive?
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@luiscuevasii indeed a good suggestion but that Acusol 830 itself is a 28% ASE in water.
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As many have said, HPC (Klucel) is the best solution. Look at some of the Minoxidil Gel (high alcohol) patents for direction.
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I have seen a few products using pyroxylin. It should be soluble in ethanol.
https://www.hpra.ie/img/uploaded/swedocuments/2160432.PA0278_015_001.479da2a9-91d8-4232-a145-f71d0c7fae69.000001Product%20Leaflet%20Approved.150506.pdf -
Who’d a thunk it… Apparently xanthan can be used to thicken glycerol. See this brand new paper on Researchgate: https://www.researchgate.net/publication/242663890_Thickening_glycerol. They say that you have to add a suitable salt to avoid stringiness. Their, very reasonable, assumption is that the salt drives the xanthan into its helix form, just like in water, avoiding the stringy coil form.
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