I found out that is quite difficult to stabilize urea in cosmetic formulations. Sometimes it can lower the viscosity of emulsions and it also can increase the pH of the cosmetic system after some time, and above pH 7 sometimes there's liberation of ammonium.
After some research I found out that is necessary to have a buffer solution to prevent pH alteration, but I am a little confused about it. Do I really need to prepare a buffer solution or just a pH adjuster (e.g. citric acid, alctic acid, sodium hydroxide) can already fix the problem? How can I prepare a buffer solution? Do I need to calculate something? I'm having trouble understanding it.
Also, anyone has any more tips about working with urea?
Thanks in advance!