Home Cosmetic Science Talk Formulating Trying to stabilize formula am i missing something??

  • Trying to stabilize formula am i missing something??

    Posted by chemicalooze on January 25, 2023 at 2:05 pm

    There is a formula for an SPF BB cream that I trying to create a sample for that has been incredibly hard to stabilize (keeps separating / going down in viscosity) and I’ve tweaked it as much as I can but feel like I am doing something wrong. Can a fresh pair of eyes take a look at it? 

    Water phase:
    Water qc
    Glycerin 0.5%
    Zemea propanediol 1%
    Hyaluronic acid 0.05%
    Extracts in glycerin 0.45%
    Caffeine 0.01%
    Niacinamide 0.02% 
    Magnesium aluminum silicate 0.45%
    Xanthan gum 0.15% 

    Oil phase: 
    Caprylic/Capric triglyceride 6.5%
    Glyceryl stearate citrate 2.5%
    Stearic acid 2.5%
    Glyceryl stearate SE 2.5% 
    Sorbitan monostearate 1% 
    Lecithin 1%
    Sunflower oil 2%
    Coconut oil 0.5%
    Shea butter 0.25%
    Tocopheryl acetate 0.02%
    UV filters 15% 

    Cool phase: 
    Decyl glucoside 11%
    Lauryl alkyl 1%
    Aromatic oils 0.3%
    Preservative 1%
    Iron oxides 5.19%
    Citric acid 0.06%

    After everything has been mixed, I used an overhead homogenizer to disperse everything. It needs to be stable around 30,000 cps but keeps separating and/or losing viscosity or coming out much too thick. The formula has already been approved so I cannot add or subtract anything, can only mess with the concentrations and procedure. Any suggestions? 

    Abdullah replied 1 year, 4 months ago 6 Members · 13 Replies
  • 13 Replies
  • Abdullah

    Member
    January 25, 2023 at 2:45 pm

    What is the pH? 
    Do you you know what each ingredient is doing in your formula? 
    For example what is 11% decyl glucoside doing there?

  • Paprik

    Member
    January 25, 2023 at 5:43 pm

    Are the UV filters solid? If so, I don’t think you have enough lipid. 
    Also do not understand much 11% Decyl glucoside. 

  • ketchito

    Member
    January 26, 2023 at 2:56 am

    I agree with the comments above. It might be the 11% of Decyl glucoside what’s causing the issue. This is a surfactant mostly used in cleansers. 

    Also, what’s Lauryl alkyl??

  • OldPerry

    Member
    January 26, 2023 at 3:23 am

    Also, it might not be enough Xanthan gum to suspend the particles. Maybe try a slightly higher percentage.

  • MarkBroussard

    Member
    January 26, 2023 at 11:20 am

    @chemicalooze:

    As noted, the Decyl Glucoside at 11% does not make any sense in this formula, nor does “Lauryl Alkyl”.  If you need to leave these in the formula, take them both down to 0.1%.  What was the logic of putting high levels of surfactant in an SPF cream?

    But, I’ll also note Iron Oxides at 5.2%?

    Also, what preservative are you using and what UV filters?  One of the preservative components may be affecting your viscoisty/stability if it contains capryly glycol, for instance.

  • chemicalooze

    Member
    January 26, 2023 at 12:24 pm

    Abdullah said:

    What is the pH? 
    Do you you know what each ingredient is doing in your formula? 
    For example what is 11% decyl glucoside doing there?

    pH needs to be 6-7. The decyl glucoside is being used as an emulsifier.

  • chemicalooze

    Member
    January 26, 2023 at 12:25 pm

    Paprik said:

    Are the UV filters solid? If so, I don’t think you have enough lipid. 
    Also do not understand much 11% Decyl glucoside. 

    Ten percent is made up of solid titanium dioxide and zinc oxide then there’s also octocrylene 

  • chemicalooze

    Member
    January 26, 2023 at 12:30 pm

    ketchito said:

    I agree with the comments above. It might be the 11% of Decyl glucoside what’s causing the issue. This is a surfactant mostly used in cleansers. 

    Also, what’s Lauryl alkyl??

    That was a typo and it should say lauryl alkane. The decyl glucoside is meant to emulsify the formula. When I’ve tried making the formula with a lower percent of the APG, it seems to break after the oil phase. Do you have any suggestions on what to make higher? 

  • chemicalooze

    Member
    January 26, 2023 at 12:34 pm

    @chemicalooze:

    As noted, the Decyl Glucoside at 11% does not make any sense in this formula, nor does “Lauryl Alkyl”.  If you need to leave these in the formula, take them both down to 0.1%.  What was the logic of putting high levels of surfactant in an SPF cream?

    But, I’ll also note Iron Oxides at 5.2%?

    Also, what preservative are you using and what UV filters?  One of the preservative components may be affecting your viscoisty/stability if it contains capryly glycol, for instance.

    The APG was meant to help emulsify everything and I guess I wasn’t seeing it as harmful in that percentage. The iron oxides are in that percent to match the client supplied product’s color. 

    The preservative system is Caprylyl Glycol, glyceryl laurate, and glyceryl undecylenate. Could you elaborate on how it would be affecting my parameters/how to address the issue? 

    The UV filters are titanium dioxide, zinc oxide, and octocrylene. 

  • MarkBroussard

    Member
    January 26, 2023 at 1:42 pm

    @chemicalooze:

    Decyl Glucoside as an “emulsifier” at 11%?  You already have Glyceryl Stearate Citrate, Glyceryl Stearate SE, Sorbitan Stearate and Lecithin in your formula.

    Your problem is two-fold:  You have way too much Decyl Glucoside, which really shoul not even be in this formula, but if you are locked-in, drop it to 0.1%.

    But, your main problem is that your preservative components generally blow viscosity of emulsions.  For that, there is no solution other than to ditch the preservative.  The only way you’re going to get it to not affect viscosity is to drop it to 0.3% or less and at that level it will be ineffective at preservation.

  • Abdullah

    Member
    January 26, 2023 at 9:02 pm

    11% decyl glucoside can be irritating.

  • ketchito

    Member
    January 27, 2023 at 12:26 am

    I agree with @MarkBroussard. Decyl glucoside is not really an emulsifier (high polar head, short alkyl part). If you want a glucoside-based emulsifier, choose Cetearyl glucoside. Check if removing Decyl glucoside solves the issue. If not, then check if the preservative is also destabilizing your system.

  • Abdullah

    Member
    January 27, 2023 at 3:21 am

    Or use lauryl glucoside if you have to use that in such high quantity. 
    Lauryl has better emulsifying, better viscosity and less foaming than decyl glucoside.

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