Home Cosmetic Science Talk Formulating Requesting Guidance for Gel

  • Requesting Guidance for Gel

    Posted by DSTANK on April 2, 2020 at 11:52 pm

    Hello all,

    I am trying to formulate a pain relief gel.

    Below is the formula:

    Ingredients %w/w
    Menthol 7.55
    Capsaicin 0.5
    Clove oil 1
    Glycerin 0.5
    Aloe Vera Juice 30
    Carbopol 980 1.3
    10% NaoH (Q.S to adjust pH) pH adjustment
    Water 28
    Isopropyl myristate 1.5
    Isopropyl alcohol 29

    Problem : The alcoholic portion with active tends to separate from Carbomer base (with Aloe, Glycerin and Water)

    Kindly guide me to resolve the issue.

    amitvedakar replied 3 years, 11 months ago 4 Members · 5 Replies
  • 5 Replies
  • EVchem

    Member
    April 3, 2020 at 11:33 am

    The first thing I would look at is if your level of IPA can dissolve all of those actives just by itself.  I also attached this guideline in case it helps. If it is separating, is it after neutralization? The large amount of aloe vera juice is going to interfere with your carbomer, you should cut that down significantly.

    What is your order of addition? That’s also going to be key here.

  • DSTANK

    Member
    April 3, 2020 at 5:07 pm

    Thank you EVchem for your response and neutralization guidelines. 
    I will go ahead and cut down on Aloe vera juice.

    Order of addition: Dissolve Actives in alcohol in one beaker. To another beaker hydrating carbopol in water, aloe juice and glycerin mixture. Once its completely hydrated added IPM and mixed well. In the end added alcoholic phase to the carbomer phase. Mix it at slow speed. (The alcohol phase does not very well blend with carbomer phase). After this step, I started neutralizing the carbomer.

    Separation description: There is carbomer gel with alcoholic phase (Orange colored with capsaicin) adhering to container walls, separated from the matrix  (Translucent whitish gel) . No precipitation is observed.

    Please me know if I am missing a breakthrough step/ingredient here. Any guidance would help

  • EVchem

    Member
    April 6, 2020 at 1:19 pm

    I’d recommend trying to neutralize before adding alcohol. You’ve got a high amount of carbomer, it really shouldn’t need to be over 1%. 980 is also not very tolerant of electrolytes, which your aloe juice is full of. If you are able to get Carbopol ultrez 21 or 20 that should help.  Hydrate the carbomer totally by itself first, then adding in glycerin/aloe/what have you. You’ll be able to see if the amount of aloe you want to add breaks the gel right away so you know to adjust your amount.

    Also, your alcohol level is too high to use NaOH as a pH adjuster, try TEA if possible or cut your alcohol. This document has lots of insights even though it’s for sanitizers with higher alcohol content.

  • mhart123

    Member
    April 7, 2020 at 1:47 pm

    You need to better solubilize the menthol.  Try adding 20% propylene glycol to your alcohol phase and that should help give you a nice smooth, clear gel.

  • amitvedakar

    Member
    April 8, 2020 at 8:09 am

    capsaicin 0.5% or 0.05%?

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