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urea ointment
hi, we try to make a 40% urea product in oil/fat base. but the urea does not disolve well enough.We have made a 40% waterbased urea cream and it looks good but in use it is not usable as it chrystalizes to 100% urea on the skin. Any tips are welcome. I am not a formulator but the owner of a EU based cosmetic company.My formulator is stuck with this project.
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13 Replies
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My formulator is stuck with this project.
40% Urea? And you wonder why the formulator is having trouble? -
Can’t you just grind the urea into the anhydrous base? It’s so polar that it’s not really soluble in anything other than water or alcohol.
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jrnb, this project was simply a bad idea. Scrap it and move on. Like Bob said, urea is water-soluble only, and it does nothing to soften skin in the solid state form.
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There are brands already making this product and 40% is a well known formulation for nail removal product. So it must be possible. I will discuss the grinding. Thank you!
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Using a 3-roll mill is probably your best choice. Other grinding methods do not cope well with high-viscosity products like ointments.
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40% is a well known formulation for nail removal product.
WHAT? Please explain! -
I saw that too. Apparently, used long enough, it will actually dissolve finger/toe nails.
https://dailymed.nlm.nih.gov/dailymed/archives/fdaDrugInfo.cfm?archiveid=27288
https://www.webmd.com/drugs/2/drug-77924/re-urea-40-topical/details
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@jrnb You should be able to triturate with glycerine for water base using a lot of elbow grease and 5-10 % glycerine to avoid crystallization on skin.I don’t know what oils you are using but you should be able to do the same with lanolin or petrolatum.
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The urea must be in fine particles and I think Merck can provide it.
You can dissolve urea in a mixture of glycerol and alcohol which can be incorporated in the simple ointment base (10% lanolin, 90% petrolatum)-
Without using an emulsifier?? And wich amount of glycerine we use,what about preservatif?? I m dealing with the same issue
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A. Lanolin is being used as the W/O emulsifier here. B. There is no absolute level of Glycerin that predictably self-preserves. Glycerin can be used as an adjunct as it decreases free water but free water needs to be tested for. C. This is a very low-water product as it is a W/O emulsion. Challenge Testing would still likely be performed. https://cosmetics.specialchem.com/inci-ingredients/lanolin
cosmetics.specialchem.com
Lanolin (Emulsifying agent): Cosmetic Ingredient INCI
Find more about Lanolin (CAS 8006-54-0) cosmetic ingredient used as a hair and skin conditioning agent. Check related commercial grades and formulations.
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Thanks a lot for your answer, i think i would refer to add a preservative, may be paraben complex?? Another question please,if we are solublising the urea in glycerine,then the aqueous phase will be 45%, or we will just considering the amount of glycerine?? Im beginner ????
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This is very helpfull. Thanks.
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