• Formulating

  Glycerin + preservative

  Posted by paulasbrito on March 6, 2018 at 4:46 pm

  Hello again guys.
  Well, maybe this is a stupid question but when you add glycerin to your formulations do you add it in the water or the oily phase?
  I am starting with this and my method is:

  - I heat the oily phase (approx 70ºC) until everything is melted
  - In a separate container I heat the water + glycerin + xanthan gum at aproxx 80ºC (and leave it for about 3 minutes at that temperature)
  - Then I mix the water+glycerin+xantham gum (until i get a clear aqueous gel)
  - then (everything still hot) I mix oily and aqueous phase until emulsifying everything and let it cool down - then preservative etc.
   Am I doing this right?
  Should I add the glycerin to the aqueous phase or the oily phase? or it doenst really matter?
  - Abou the preservative (I am using Benzyl alcohol + dehidroacetic acid (Cosgard)) and adding it to the already prepared emulsion when cooled down at 30ºC

  Maybe it would be better do dissolve the preservative in the aqueous phase….
  But then I would have to let the aqueous phase cool down before emulsifying it…

  Oh well… get ready to hear from me a lot these days.   
  Thank you so much!

  em88 replied 6 years, 11 months ago 3 Members · 3 Replies
• 3 Replies

• 

  OldPerry

  Professional Chemist / Formulator

  March 6, 2018 at 6:36 pm

  Glycerin is added to the water phase

• 

  paulasbrito

  Member

  March 6, 2018 at 10:22 pm

  thanks Perry!
  And the preservative? Should I add it too in the water phase after cooling down?

• 

  em88

  Pharmacist

  March 7, 2018 at 12:37 pm

  It appears to me that Cosgard has an other composition.
  How are you going to add the preservative in the water phase after cooling down? You are going to mix both phases at probably 60-70 C.
  Just add it after the emulsion is prepared and cooled at 25-30 C. 

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