• Formulating

  Vitamin C + Alpha Arbutin Serum - Stability Issue

  Posted by AMS on April 26, 2024 at 7:54 am

  I have prepared the following water base serum formulation: Ethyl Ascorbic Acid 8.0%, PPG 3.5%, Glycerine 2.5%, PEG 40 2.0%, D Panthenol 2.0%, Niacinamide 3.0%, Alpha Arbutin 4.0%, Phenoxyethanol 0.8%, Vitamin E 0.5%, Alantoin 0.1%, Aloe Vera 200x 0.05% and balance water.

  Two months storage in ambient showed reduction in viscosity from 860 to 470 cps and in oven at 45 deg C, the viscosity reduced to 180 cps. The colour of serum also changed from initial Pale Yellow to Dark Brown.

  I understand that Vitamin C serum tends to oxidize over time but the viscosity reduction is too much in two months time and may lead to consumer dissatisfaction in application. Any suggestions please.

  Regards,

  cosmetic_chemist_vietnam replied 2 days, 21 hours ago 4 Members · 4 Replies
• 4 Replies

• 

  chemicalmatt

  Member

  April 26, 2024 at 12:32 pm

  @AMS It is not clear what is described by “PPG” or even “PEG-40” and those polyols (we know what those acronyms mean) are your key thickening ingredients. E.g. PPG-15 Stearyl Ether + PEG-40 Stearate: now we have something to go on. That combo would produce a nice emulsion, BTW, one that is oxidatively stable as well. You might also use a Poloxamer PPG/PEG block copolymer to achieve 1000 cps sustainably. But alas…

  • 

    AMS

    Member

    April 29, 2024 at 7:51 am

    Thanks, PPG (polypropylene glycol) used in the formula. I have added now ferulic acid @0.5% and increased the level of Vitamin E from 0.5% to 1.0%. Hope this would help in keeping the viscosity stable. Any suggestion, look forward to.

    regards,

• 

  ketchito

  Member

  April 29, 2024 at 8:35 am

  As @chemicalmatt mentioned, it’d be nice to have full INCI names for your ingredients. If PEG-40 is PEG-40 hydrogenated castor oil, then your Polypropylene glycol won’t probably be enough to give thermal stabilization of your viscosity.

• 

  cosmetic_chemist_vietnam

  Member

  May 3, 2024 at 10:07 pm

  In my opinion, you should use gelling agents like xanthan gum or sodium hyaluronate. You can also consider using Alpha Tocopherol 1% plus Ferulic Acid 0.5% to increase stability of Vitamin C derivative. I have never used the combination of EAA and Alpha Arbutin before, so I am not sure about the interaction between this 2 materials.

  • This reply was modified 2 days, 21 hours ago by  cosmetic_chemist_vietnam.

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