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Home Cosmetic Science Talk Formulating Dissolving Allantoin

  • Dissolving Allantoin

    Posted by Mandy007 on April 27, 2022 at 1:33 pm

    I am using 0.5%  Allantoin to formulate a O/W Emulsion.  In the beginning stages I used glycerin to dissolve the allantoin and then added the mixture to the cool down phase of my mixture but then I read that 1,3 propanediol is a better solvent to dissolve it.  My question is how long should I leave the allantoin to dissolve in the 1,3 propanediol ? I left mine to dissolve for about 6 hours and I could still see some undissolved bits.  By the way, I am dissolving 0.5% allantoin in 2.5% 1,3 propanediol.  Grateful for some guidance.  

    fareloz replied 1 year, 1 month ago 9 Members · 14 Replies
  • 14 Replies
  • ketchito

    Member
    April 27, 2022 at 2:03 pm

    @Mandy Did you try adding allantoin directly to the emulsion, during the cool down phase?

  • MarkBroussard

    Professional Chemist / Formulator
    April 27, 2022 at 2:05 pm

    @Mandy:

    Two options:  (1) Heat the Allantoin + 1,3-Propanediol to 50C … should dissolve right away.  Or, as @ketchito mentioned, just add the Allantoin directly to the emulsion when it cools to 50C and homogenize.  The Allantoin will dissolve in the emulsion.

  • Mandy007

    Member
    April 27, 2022 at 4:44 pm

    ketchito said:

    @Mandy Did you try adding allantoin directly to the emulsion, during the cool down phase?

    No I have not, I have always tried to dissolve it in a solvent first at room temperature then add it to the cool down phase. 

  • Mandy007

    Member
    April 27, 2022 at 4:46 pm

    @Mandy:

    Two options:  (1) Heat the Allantoin + 1,3-Propanediol to 50C … should dissolve right away.  Or, as @ketchito mentioned, just add the Allantoin directly to the emulsion when it cools to 50C and homogenize.  The Allantoin will dissolve in the emulsion.

     If I heat the Allantoin in the 1,3 Propanediol, how do I avoid recrystallization ?  I know allantoin is famous for recrystallizing if heated hence why I have not tried any methods that require me to heat it. 

  • MarkBroussard

    Professional Chemist / Formulator
    April 27, 2022 at 5:00 pm

    @Mandy007

    As long as you keep the temperature below 55C and Allantoin at or below 0.5% you will generally not get recrystallization.

  • Mandy007

    Member
    April 27, 2022 at 8:07 pm

    @Mandy007

    As long as you keep the temperature below 55C and Allantoin at or below 0.5% you will generally not get recrystallization.

    Thank you. I will try as you suggested. 

  • Graillotion

    Member
    April 27, 2022 at 8:24 pm

    Mandy007 said:

    @Mandy:

    Two options:  (1) Heat the Allantoin + 1,3-Propanediol to 50C … should dissolve right away.  Or, as @ketchito mentioned, just add the Allantoin directly to the emulsion when it cools to 50C and homogenize.  The Allantoin will dissolve in the emulsion.

     If I heat the Allantoin in the 1,3 Propanediol, how do I avoid recrystallization ?  I know allantoin is famous for recrystallizing if heated hence why I have not tried any methods that require me to heat it. 

    I think the main reason people get recrystallization is because they are trying to over saturate the solution with allantoin.  Keeping your levels at the .5, you should be fine.  However, to be nit-picky…it should be .5% of your water soluble ingredients…hehehe… not .5% of total formula.

    As Mark said…a little heat…should make that slip right into solution…. but not necessary. 

  • Rockstargirl

    Member
    April 28, 2022 at 1:01 am

    I’ve always just tossed it in the water mix and poof it’s gone. And I use 3%. 

  • Microformulation

    Professional Chemist / Formulator
    April 28, 2022 at 1:43 am

    I’ve always just tossed it in the water mix and poof it’s gone. And I use 3%. 

    You may want to check on that. The listed solubility in water cited in a Technical document is 0.57 g/100 mL (at 25 °C) and 4.0 g/100 mL (75 °C). 
  • Abdullah

    Entrepreneur
    April 28, 2022 at 12:10 pm

    @Microformulation can you explain this please.

    Does 40g/L mean in 1 litter water mix 40g allantoin or in 960ml water add 40g allantoin that becomes 1L?

  • chemicalmatt

    Member
    April 29, 2022 at 5:25 pm

    Here’s a hack for allantoin solvation: urea greatly increases allantoin solubility in water. Add them both: one a skin protectant the other a skin softener.

  • Graillotion

    Member
    April 30, 2022 at 2:39 am

    Here’s a hack for allantoin solvation: urea greatly increases allantoin solubility in water. Add them both: one a skin protectant the other a skin softener.

    @chemicalmatt I use a slightly different version of urea, HydroVance, aka: Hydroxyethyl Urea.  Would you say this hack works with this as well?

    I guess the next logical question would be, is there any (proven) benefit, taking allantoin higher than .5%?

    Aloha.

  • Graillotion

    Member
    May 2, 2022 at 7:49 pm

    .

  • fareloz

    Member
    May 3, 2022 at 8:14 am

    Some sellers say that betaine helps to dissolve allantoin