Need help stabilizing formula

Hi Guys,

Can some one see what missing? I have tried and tried with always same result. Cream not stable

Please help

Here is the formula:

water 65,7
Carbomer 1
EDTA 0,1
Phenoxyethanol 0,7
Sodium Benzoate 0,5
Propylene glycol 2
Glycerin 3
Ceteareth-12 1,5
Paraffinum liquidum 5
Cetyl alcohol 6
Vegetable oil 12
D-Panthenol 1
TEA 1,5

Comments

  • PharmaPharma Member, Pharmacist
    nabilram said:
    ...
    Can some one see what missing?...
    A second emulsifier.
    I suppose 1,5% ceteareth-12 is not enough even if you have cetyl alcohol in your formulation (BTW 6% is a lot and hence tends to act like a wax/oil rather than a "co-emulsifier").
  • Hi Pharma,

    Thanks for your help. 6% cetyl Alcohol is to give it consistency and thickening.

    I have made the following changes but still same results.

    1- Added 1.5% Ceteareth-20 as co emulsifier
    2- Tried without carbomer and 2 emulsifiers Ceteareth-20,12




  • It not about how many emulsifiers but more about which ones. You usually want different types of emulsifiers. Can you source Arlacel 165? It's quite bulletproof. You can also mix Ceteareth-20 with Glyceryl Stearate SE.

    There is also nothing wrong with adding carbomer as it improves stability.
  • EVchemEVchem Member
    I have too many questions but hopefully it will help you find any other issues

    In what way is it not stable? Does it form properly and then fail overnight at room temperature, or after some time in an oven? Does it just not come together? 

    Which carbomer are you using?  To me 1% is the upper limit, is this much necessary because you have a decent amount of salt (sodium benzoate)?

    Most importantly, how are you mixing- can you give a  breakdown of what phases and what order you are adding things in, what temperature you are heating each phase to, etc?
  • It not about how many emulsifiers but more about which ones. You usually want different types of emulsifiers. Can you source Arlacel 165? It's quite bulletproof. You can also mix Ceteareth-20 with Glyceryl Stearate SE.

    There is also nothing wrong with adding carbomer as it improves stability.

    I don't have those emulsifiers. It will take me some time to source them but definitely will see to it

    Thank you
  • EVchem said:
    I have too many questions but hopefully it will help you find any other issues

    In what way is it not stable? Does it form properly and then fail overnight at room temperature, or after some time in an oven? Does it just not come together? 

    Which carbomer are you using?  To me 1% is the upper limit, is this much necessary because you have a decent amount of salt (sodium benzoate)?

    Most importantly, how are you mixing- can you give a  breakdown of what phases and what order you are adding things in, what temperature you are heating each phase to, etc?
    Hi Evchem,

    it form properly and then fail overnight at room temperature

    Carbomer is 940 type.  i have tested it and working fine

    Here are the phases


     A. water 65,7
    A. Carbomer 1
    A. EDTA 0,1
    C.Phenoxyethanol 0,7
    A. Sodium Benzoate 0,5
    A.Propylene glycol 2
    A.Glycerin 3
    B.Ceteareth-12 1,5
    B.Paraffinum liquidum 5
    B.Cetyl alcohol 6
    B.Vegetable oil 12
    B.D-Panthenol 1
    C.TEA 1,5



  • sorry forgot to mention temperature. Its 70° each phase then B in A cool down to bellow 40 and add phenoxyethanol
  • If you are willing to use 1.5%!!! of TEA, then why wouldn't you add it to the watephase instead of cool down and add 3% of stearic acid to your oil phase? I don't like TEA-stearate personally but that would be a cheap additional emulsifier that will improve stability. The pH should still be high enough to neutralise carbomer. If you are using TEA for neutralising carbomer it's too much.
  • If you are willing to use 1.5%!!! of TEA, then why wouldn't you add it to the watephase instead of cool down and add 3% of stearic acid to your oil phase? I don't like TEA-stearate personally but that would be a cheap additional emulsifier that will improve stability. The pH should still be high enough to neutralise carbomer. If you are using TEA for neutralising carbomer it's too much.
    I dont have stearic acid at hand. I have either Ceteareth-20 or polysorbate 80
  • Chemist77Chemist77 Member, PCF student
    I think @ngarayeva001 makes a very strong point here, can you not neutralize the carbomer before adding the oil phase. But that quantity is insanely high given the fact it's a cream and it will become very thick to mix. Reduce to maybe to 0.25% and adjust the TEA accordingly. 
  • It is much easier to work with carbomer when you add it to the oil phase.
  • EVchemEVchem Member
    I also think thickening the water phase could be helpful, with that much sodium benzoate you probably need additional carbomer.  You could always add the TEA to the hot water phase A and disperse the carbomer in the oil phase so it thickens during emulsification.

    940 is the one processed with benzene right?  I doubt it's very resistant to salts but I don't know what else you have available.

    Honestly carbomer and the sodium benzoate are probably  not a good combination. The Sodium benzoate will work better the lower the pH (at least below 5.5) but the carbomer will thicken best close to pH 6-7. I would swap one of those out. 

  • MarkBroussardMarkBroussard Member, Professional Chemist
    @nabilram

    You have 17% total oils phase and 6% Cetyl Alcohol, both of which are too high.  Lower your total oils to 11% or so and Cetyl Alcohol to 2%.  As noted by others, add a second emulsifier, each at 2%.  Hydrate your Carbomer in the water phase, form the emulsion and gel the Carbomer as the last step.

    I'm assuming you're trying to make some sort of hair cream?  
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • FekherFekher Member, Professional Chemist
    edited August 6
    Actually vegetable oil is not precise because evry vegetable oil has his adequat needed hlb seeing your Lol it seems that you didn't use the adequat blend of emulsifiers neither the adequat level.
  • I think 12% Vegetable Oil in emulsion is significantly high.  In most of the emulsion formulas I passed by, it didn't exceed 5% in the sum of all oils in the formula
  • In addition to the % of oil, it is the mixing issue: What kind of mixers are you using? is it Ultra Mixers, Over Head Mixers, or Homomixers? For what speed and for how long? these factors can make a big difference in the Stability Issue beside the temperature
  • nabilramnabilram Member
    edited August 8
    Hi Guys,

    Thank you all for your help. The oil content is too high, i believe now. Evchem suggestion to forgo sodium benzoate is a good idea.

    I have an ultra mixer and a stirrer as equipments.

    I will do some changes based on your input and get back with some feedback
  • chemicalmattchemicalmatt Member, Professional Chemist
    EDTA (Na2?), sodium benzoate - all those electrolytes, its amazing it stayed together in the first place. Friends don't let friends use electrolytes in the same formula as carbomers or any other acrylate copolymer. Drop those and your goop will stay together a whole lot better. Adding 1% stearic acid won't hurt either as ngaryev suggests. That is a lot of TEA for 1.0% Carbopol.
  • @chemicalmatt, I generally avoid electrolytes in most of my o/w formulations as I use Aristoflex AVC quite often. But as per my observations 0.1-0.2% of disodium or tetrasodium EDTA do not have negative effect on viscosity. 
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