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45% Urea Cream
Hi Brains Trust
I’m trying to develop a 45% Urea Cream, but finding I’m having trouble dissolving the urea. After cool down, it re-forms crystals.
Am I trying to do the impossible? I note that the only other 45% urea creams on the market are Alibaba, Amazon or Temu, so are highly dubious.
However, my client is demanding!
Current formula is stable but crystalline.
Please see attached percentage and ingredients.
Any advice would be appreciated.
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13 Replies
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Its a tricky formula. You generally need a 1:1 urea and water, that leaves only 10% for the rest of the ingredients, most of which is preservative, ph ingredients…Because urea is a crystal, it tends to crystalize. Are you trying to make a cream? Your best bet with such high urea is to experiment with a water and urea 1:1 and forget about dreams for something emollient. Glycerin tends to help but unless you use an airtight jar, it’ll dry and crystalize.
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This reply was modified 3 days, 2 hours ago by MaidenOrangeBlossom.
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Thanks for your kind response. Yes, I’m trying to make a cream, but as you can see, I quickly run out of room in the formula for anything else. Perhaps I’ll just propose a gel-based emulsion.
I have this as a reference product, although I’m starting to doubt the legitimacy of it.
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I don’t know how they did that, if it can be done that’s incredible. The packaging looks fairly air tight. They must have figured out a way to incorporate the urea without a 1:1 water ration and used PG instead. I’ve never used PG due to the potential allergens but the heels would probably be ok.
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Yes, it seems unlikely it’s real.. looking at all the ingredients in addition to the 42% urea and 2% salicylic acid! I wouldn’t use PG either, but even if it was glycerin, it’s still an unbelievable formula.
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This reply was modified 3 days, 2 hours ago by
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Although I don’t agree with having high doses of hygroscopic humectants as the only way to achieve moisturization (emollients and occlusives are also needed for a full benefit), you can certainly make a cream with high doses of urea. You can check at this patent: US20050042182A1 - Topical compositions of urea - Google Patents
Now, get rid of unnecesary ingredients and focus on the ones that make the emulsion (don’t forget about the glycol -some papers suggest a mixture of water:PPG is the way to go-, structuring agents, preservatives and a chelant, of course). Adding urea during the cool-down process makes it more prone to crystallization since there’s less free water to dissolve it. You could alternatively add urea in the water phase at the start of the process (T increases urea solubility) and make your emulsion perhaps at 60-65°C, but keep at this T not for long….so the emulsion should be fast and furious.
patents.google.com
US20050042182A1 - Topical compositions of urea - Google Patents
US20050042182A1 - Topical compositions of urea - Google Patents
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That patent wasn’t much help. It’s a patent for a product for urea content between 20 and 48%, if I read it correctly. And it’s in a propellant so it foams, like a shaving cream I assume. Thanks anyway!
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You are WAY over the saturation point for urea there, which is right around 45%. IF all you had in this was water and 45% urea you would still be in danger of precipitation as soon as it cooled below 15C. Your sources are flatly mistaken in calling for that amount. The product medical doctors use to dissolve nails (overnight) is only 40% urea in water stabilized with a lactate buffer, just to give you reference. And, what’s with all that triacetin?
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Is that 40% solution just in water or with humectants as well? Do you know what it’s called so I can look it up? Thank you!
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Thank you for that info. My client is actually a doctor, and very demanding. She insisted that I incorporate the triacetin at a 1:10 ratio with the urea. Apparently it helps to stabilize it. But yeah, I’m really not enjoying this project. I’m not sure where’s she’s getting her information from, but I’m glad to hear about this 40% overnight treatment.
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The doctor is likely mistaken about the T. Most doctors don’t take pharmaceutical or compounding courses so they often don’t understand that urea cream doesn’t require an active pharmaceutical ingredient like T. Most people want one product to do everything but whatever this is treating, it won’t be as effective. For a 45% urea product, you would literally only have room for maybe 2-3 drops of oil, pea size amount of butter, a dimes worth of humectant. Best to maybe have 2-3 different products.
If she insists on a 45% product, there wont be any room to add an medical grade anti fungal etc.
For example for stubborn heel cracks, a 40% urea is a good enough but then adding a second layer of jojoba with glycerin is very effective but worth the mess, and of course any topical meds a doctor might prescribe. Once you start working with urea you’ll be able to see strong limitations. It will generally always end up crystalizing after some months. I’m sure there are chemists who made the product that you found who have the capability but I also wonder what machinery they’re using too.
With urea, you have to add a chelator and at min a 1:1 water ratio for optimal stability. I am not sure where PG comes in but would be worth a try. I think its interesting if someone has figured a way to avoid the crystallization.
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I might see if I can make a simple gel with it… 45% in a cream base just seems a bit unattainable at this point. I’ve even seen claims of 60% urea in a stick format which I find highly dubious.
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I can’t see how it would be stable at 60%, I’m guessing that either people heat it lightly to dissolve the crystals or its sold in small amounts. Its such a sticky solid ingredient that if there is a way to process it, I’d like to know.
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Yes, I’m imagining it’s crunchy and crystalline!
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