Please help to fix my Ferulic Acid + Ethyl Ascorbic Acid serum

Hello everyone!
Very happy to join the community. 
I'm working on an emulsion serum with Ferulic Acid and Ethyl Ascorbic acid. I worked with several emulsifiers like Montanov 68, L, and 202, Olivem 1000(they were not light enough or i didn't like their feeling) and Eumulgin SG (this sample was seperated after 10-20 days) but finally tried Natragem EW and it looked perfect and my client finally approved it.  For 2 months i stored each sample in 4C, RT and for almost 3 days i stored it in 45C when i first made that batch. 3-4 days ago i discovered that they are separating. Before i realised the seperation, I've made new samples and sent it to the lab for stability testing,i guess they will fail eventually, this was heartbreaking for me but i wanna understand why it is happening, so that i can learn. I don't know so many exprerienced cosmetic chemists so if you check my formula and tell me what did go wrong, i'd be appreciated. 

A
AQUA 58,8
ETHYL ASCORBIC ACID 0,5
NIACINAMIDE 3
PENTAVITIN 0,5
ALLANTOIN 0,1
NATRLQUEST E30 0,1
B
PROPANEDIOL 20
FERULIC ACID 0,2
C
GLYCERIN 3
XG 0,3
D
NATRAGERM EW 4
CAPRYLC CAPRYC TRIGLISERIDE 5
SAFFLOWER OIL 0,5
JOJOBA OIL 0,5
E
LICORICE EXTRACT 0,5
GEOGARD 221 0,8
CENTELLA ASEITIACA EXTRACT 0,5
FRANKINCENSE EO 0,2
PALMAROSA EO 0,3
LAVENDER EO 0,2
OATMEAL EXTRACT 0,5
TOCOPHEROL 0,5

My method is: Prepare phases - Add Phase B to Phase A, add C to A+B, heat A+B+C and D separetly to 80C,  homogenise for 4-6 mins in high shear- low shear when cool down, below 40 add phase E and mix. Adjust the pH 4,5-5,00.

I have 2 questions; 
1-What do you think i can do to fix this formula?
2-Do you expertises think if i switch to a gel serum base, my job would be easier? Without lipid phase or emulsification, do you think i'd have more chance to get better stability results? 

Thanks for reading and sharing your ideas!

Comments

  • PROPANEDIOL 20 - I think this amount of propanediol can lower the viscosity of your formula and possibly contribute to its destabilization.
    What benefits do you expect from ferulic acid? If you want to improve vitamin C stability, I don't think it is necessary in this case because you are using a stable form of vitamin C.
  • majibomajibo Member
    PROPANEDIOL 20 - I think this amount of propanediol can lower the viscosity of your formula and possibly contribute to its destabilization.
    What benefits do you expect from ferulic acid? If you want to improve vitamin C stability, I don't think it is necessary in this case because you are using a stable form of vitamin C.
    Thanks for responding! 
    Normally i don't like mixing a lot of actives or ingredients but It is just what my customer asked for, as you mentioned, there is no need to add ferulic acid in this case. 
    I used propanediol for dissolving Ferulic acid, i made a couple of tests and with this ratio i was able to obtain a clear solution when mixed into water.

    I have 2 more emulsified serums with this base, has no propanediol in it, but their samples are not old enough to see if there will be destabilization. I'll see if the lab discovers before me.

    Do you see any other uncompetable ingredients, weird percentages or a major error in the formula? 
  • Is ethyl ascorbic acid not stable on its own? I’m curious why you need the ferulic acid? For knowledge too please!
  • majibomajibo Member
    Is ethyl ascorbic acid not stable on its own? I’m curious why you need the ferulic acid? For knowledge too please!
    It is stable on its own, no need to add it to this formula for protecting the formula, but if you use L-ascorbic, then you may want to use it for stabilisation. I guess you may get antioxidant benefits if you adjust to a specific pH.
  • Maybe you could try Ethyl Ferulate (ferulic acid ester) instead of ferulic acid? In emulsions according to the manufacturer you can use it at 2%. Even if it is optimistic, 0.2% should not be a problem.
  • majibomajibo Member
    edited May 5
    Maybe you could try Ethyl Ferulate (ferulic acid ester) instead of ferulic acid? In emulsions according to the manufacturer you can use it at 2%. Even if it is optimistic, 0.2% should not be a problem.
    Thanks for the advice! I'll check with the suppliers if they have Ethyl Ferulate. So do you think Ferulic Acid may caused the problem?
  • No, I'm still thinking 20% propanediol is the problem, but you need it to dissolve the ferulic acid. As far as I know, Ethyl Ferulate has only two manufacturers:
    https://www.gfn-selco.de/en/productsearch/ethyl-ferulate-cos
    https://www.gfn-selco.de/en/products/products-a_z/ethyl-ferulate-natural
    You can try also ethyl ferulate already dissolved in sunflower oil:
    https://www.rahn-group.com/en/cosmetics/product/9/
  • majibomajibo Member
    No, I'm still thinking 20% propanediol is the problem, but you need it to dissolve the ferulic acid. As far as I know, Ethyl Ferulate has only two manufacturers:
    https://www.gfn-selco.de/en/productsearch/ethyl-ferulate-cos
    https://www.gfn-selco.de/en/products/products-a_z/ethyl-ferulate-natural
    You can try also ethyl ferulate already dissolved in sunflower oil:
    https://www.rahn-group.com/en/cosmetics/product/9/
    Thank you very much for your time, info and kind sharings!  i'll give another try for dissolving ferulic in a lower percentage. May be i was mistaken, i'll retry it. 
    I'll try to reach the distributors of the products.
     Also see the other serums without propanediol if they fail. I'll keep updated here. Again, thanks a lot for your responds!
  • majibo said:thanks 
    Is ethyl ascorbic acid not stable on its own? I’m curious why you need the ferulic acid? For knowledge too please!
    It is stable on its own, no need to add it to this formula for protecting the formula, but if you use L-ascorbic, then you may want to use it for stabilisation. I guess you may get antioxidant benefits if you adjust to a specific pH.

  • chemicalmattchemicalmatt Member, Professional Chemist
    edited May 10
    @majibo You'll want to heed the advice of @grapefruit22 in reducing the polyol content there, but I think your main problem here is too much reliance on so very little emulsifier and hoping xanthan gum can carry the burden of rheology stabilization. The total polyglyceride fatty acid (PEFA) content of Croda's NatraGem EW (try to use correct spelling next time, please) is less than 2.0% solids in your formulation. This is a mixed/multi ester PEFA, the least likely to stand on its own. You need a buddy emulsifier in there. I'd employ a discrete monoester PEFA such as Polyglcyeryl-4 Stearate, Polyglcyeryl-6 Oleate, etc. or another chemistry such as a fatty acid carboxylate. I just presented a paper on this subject so I know whereof I speak. Croda's lit - like  so many other specialty chemical suppliers' - must always be subject to critical analysis.  In this case that NatraGem system will not work on it's own without a helper. Finally, xanthan gum is another substance abuse problem among cosmetic formulators and I think there needs to be an intervention. 

  • Bill_TogeBill_Toge Member, Professional Chemist
    edited May 11
    also, ethyl ascorbic acid is only stable relative to ascorbic acid: it'll go brown in aqueous formulas, but it'll take much longer to do so
    the big advantage it has over ascorbic acid is that it's much more soluble in non-aqueous solvents
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • majibomajibo Member
    @majibo You'll want to heed the advice of @grapefruit22 in reducing the polyol content there, but I think your main problem here is too much reliance on so very little emulsifier and hoping xanthan gum can carry the burden of rheology stabilization. The total polyglyceride fatty acid (PEFA) content of Croda's NatraGem EW (try to use correct spelling next time, please) is less than 2.0% solids in your formulation. This is a mixed/multi ester PEFA, the least likely to stand on its own. You need a buddy emulsifier in there. I'd employ a discrete monoester PEFA such as Polyglcyeryl-4 Stearate, Polyglcyeryl-6 Oleate, etc. or another chemistry such as a fatty acid carboxylate. I just presented a paper on this subject so I know whereof I speak. Croda's lit - like  so many other specialty chemical suppliers' - must always be subject to critical analysis.  In this case that NatraGem system will not work on it's own without a helper. Finally, xanthan gum is another substance abuse problem among cosmetic formulators and I think there needs to be an intervention. 

    @chemicalmatt Hello, thank you very much for your informative comments!

    Ok, so i thouhgt NatraGem EW would handle different oil percentages with different polarity of oils-that's what Croda told me-.  My mistake was thinking about percentages, i thougt this emulsifier would handle %6 percent of oils. You are totally right about being critical about what suppliers say, even if it is a mixture, i'll never rely on just one emulsifier now on. I should probably dive into emulsifiers deeper, do you have any source to advice for me to learn? Thanks for the co-emulsifier advices. 

    This formula should meet Organic&Vegan standarts so i'm not sure what more option i have about replacing Xanthan Gum. I'd rather use Sclerotium Gum but i couldn't find it in here, that's why i had to rely on Xanthan Gum. 

    Thanks again and again for your time!
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