Home Cosmetic Science Talk Formulating Questions about Urea.

  • Questions about Urea.

    Posted by MJL on April 1, 2019 at 1:09 am

    Hi, 

    I have a few questions about Urea. 

    1) Is it hard to “stabilize”?
    - Does it degrade or precipitate? Under what conditions?
    - Does it always change the pH of a product? Are there ingredients to add to prevent pH shifts? 

    2) Is there any difference at all between the various forms of Urea: Hydroxyethl, Imidazolidinyl, Diazolidinyl, and Urea USP? 
    - Is one form more stable/easier to work with than others?
    - Do ALL forms of Urea release formaldehyde?

    Thanks for your time. 

    MJL replied 5 years ago 4 Members · 5 Replies
  • 5 Replies
  • em88

    Member
    April 1, 2019 at 7:23 am

    1) Is it hard to “stabilize”?
    Yes
    - Does it degrade or precipitate? Under what conditions?
    It degrades. Water and temperature presence are enough.
    - Does it always change the pH of a product? Are there ingredients to add to prevent pH shifts? 
    Yes. You need to add a buffer system

    2) Is there any difference at all between the various forms of Urea: Hydroxyethl, Imidazolidinyl, Diazolidinyl, and Urea USP? 
    Not every compound with “urea” in the name is urea! Check the molecule to understand. 
    - Is one form more stable/easier to work with than others?
    Urea is only one. 
    Structural formula of urea
    - Do ALL forms of Urea release formaldehyde?
    Probably 

  • Aziz

    Member
    April 1, 2019 at 6:12 pm

    @em88 thanks for your valuable information . 

  • bill_toge

    Member
    April 1, 2019 at 10:03 pm

    em88 said:

    - Does it degrade or precipitate? Under what conditions?
    It degrades. Water and temperature presence are enough.

    that’s a new one on me - amides like urea are usually stable unless you have a lot of alkali present
    just out of interest, what does it degrade to?

    - Do ALL forms of Urea release formaldehyde?

    Probably

    only urea/formaldehyde condensates, e.g. imidazolyl urea, do this
  • em88

    Member
    April 3, 2019 at 2:09 pm

    Bill_Toge said:

    that’s a new one on me - amides like urea are usually stable unless you have a lot of alkali present

    There are many articles that mention a degradation of urea in NH3 and CO2.
    I’ve noticed myself an increasement of pH over time. 
    In creams is even easier to spot the bubbles of CO2. 
    https://www.ncbi.nlm.nih.gov/pubmed/25043489
     
    Indeed, taking in consideration that there are covalent bonds, urea should be stable, but in my experience urea was not stable.

    Bill_Toge said:
    only urea/formaldehyde condensates, e.g. imidazolyl urea, do this

    My mistake, was thinking about something else.  :) 

  • MJL

    Member
    April 7, 2019 at 3:02 am

    Thank you, @Bill_Toge

Log in to reply.