Whitening Cream too thick and not spreadable

edited August 13 in Formulating
I've recently formulated a skin whitening cream but the problem is that it is too thick and does not spread easily on the skin. 


Carbomer - 0.1%
TEA -2%
Metyle paraben - 0.1%

Borax - .7%
Glycerin - 2%
Propylene Glycol 1%
PEG 1%

White Oil - 1%
Steric Acid - 7%
Cetyl Alcohol - 6%
Lanolin - 0.3%
PP - 0.07%
Vitamin E - 3%
Almond Oil - 5%
Arbutin - 1%
Kojic Acid - 4%


Another problem is that the cream is causing bit burning sensation on some skin types 

Comments

  • Stearic acid and Cetostearyl alcohol ratios are through the roof, you should consider decreasing their percentage, or replacing them with something that has a lower melting point (I would recommend some Isopropyl Myristate and/or Caprylic/Capric Triglycerides). This should take care of the high viscosity of your product.

    As for the burning sensation I think it may be due either to the Borax or the Kojic Acid, or to both. So I would recommend removing the Borax, and reducing the Kojic Acid ratio (maybe halve it).
  • Sorry, Cetyl alcohol instead of Cetostearyl alcohol.
  • I find that to dilute weak acid to control concentration and pH are most effective way. Irritating is from pH too low. Do you measure pHon your final product?
  • Yes, the pH stays between 5.5-7

  • edited August 9
    1. You need a better emulsification system.  Borax??
    2. You can add a rapidly spreading (low angle) emollient to increase spreadability and to get an elegant skin feel.
    3. Both Kojic Acid and Arbutin are irritating, Hence they are hardly ever used together.
    4. Why 3% Tocopherol? This is actually likely to cause rancidity at this level, not prevent it.
    5. Why so much TEA (Triethanolamine) to Carbomer? Your carbomer level is at a very low level. The distributor of Carbopols recommends closer to a 1.5 TEA/1 Carbomer ratio.
    6. Only PET/testing will absolutely determine the answer, but I would postulate that you may have an under-preserved product with only Methylparaben at 0.1% alone.

    That is my initial impression.


    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications.
  • The pKa of Kojic acid is 7.6 
    when pH = 7.6 the free acid is 50%
    the most active of kojic acid and irritation is reduced.

    this is concept, I do not have experienced on kojic. 
    On glycolic acid, ph = 3.8 the irritation is less than ph= 3.4
  • edited August 11
    @Dtdang Yes, but since there is no emulsifier, the final pH is indeterminate. Also, it is a well-accepted fact that Kojic acid is unstable and that Kojic acid can be irritating. Its use is limited by regulatory standards in most regions. It also is really most effective in certain Fitzpatrick Skin types and not the best choice for age-related changes in skin color. For Whitening, it is best addressed to a Western African demographics, Fitzpatrick Type VI.
    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications.
  • @wasif234 if you want a natural stem then maybe phenoxyethanol/ethylhexylglycerin along with Stearic acid. Maybe you have too many actives and the chemistry is not balanced good luck Catherine 
    Dr. Catherine Pratt
    (B.Sc with HONS I , Ph.D Analytical/Organic Chem and Microbiology), Cosmetic Chemistry IPCS)
  • Regarding spreadability, it’s clearly due to amounts of stearic acid and cetyl alcohol. Try to reduce stearic to 2% max. Or don’t use
     it at all.  2-3% of cetyl and  0.2% of carbomer should improve spreadability.
  • They need to improve the emulsification system. Until then any existing drag is theoretical, can drive a revision BUT is not really relevant for the most part.
    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications.
  • Thanks a lot for your replies. I forgot to mention that I'm using kojic acid dp and tried after reducing % of steric acid and cetyle alcohol, it has improved the spreadability of the cream. Is there any emulsification element that is recommended to add in the formula?
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