L-Ascorbic Acid and is protein encapsulated????????? Any Input

mflick1mflick1 Member
edited February 2014 in Formulating
Hello, 

I was hoping someone could help shed light on the below for me. I have a customer with a Vit C serum which they claimed was 10% Vit C. I had it tested only to find that 2.2% was actually in there. When I came forward with this information, the below response is what I received. Does this make sense to anyone? Any helpful comments are appreciated :-) I have some thoughts but not sure if they are correct. 

"One form we use is 7% L-Ascorbic Acid and is protein encapsulated to help stabilize it and prevent oxidation, the second form is 3% pure L-Ascorbic Acid.  What we found from the lab tests is that the protein encapsulated L-Ascorbic Acid will not show up on a test for L-Ascorbic Acid because it's encapsulated in the protein.  Our lab tests showed Vitamin C levels of 2.9%, so the samples we tested and the samples you had tested are only picking up the L-Ascorbic Acid not encapsulated in protein."

Also, isn't there a test for encapsulated product?

Thanks

Comments

  •  I guess the best way would be to speak with the manufacturer to supply an assay method for protein encapsulated vitamin C. Most suppliers would supply this (well, in pharmaceutical fields at least).

    However, I have my doubts - it doesn't add up to me.
  • gfeldmangfeldman Member
    edited February 2014
    It seems unlikely that bound L-ascorbic acid would not disassociate during HPLC analysis (due to organic solvents involved, ect), but not having worked with bound Vit C in the past I cannot say for sure. What I can say is that if you degrade the proteins with high heat and/or 6M Guanidinium chloride they will unfold, releasing any bound L-ascorbic acid. Assay the solution again after doing so and you should be able to find out for sure.

    (^^ If you want to go through all that trouble, otherwise use a vendor that is more upfront with you about the materials you are working with)
  • It would probably be easier to use a protease and a low pH  to digest the proteins and release the vitamin C - but there is also the danger of the Ascorbic acid would oxide and disappear anyway.


  • AvickAvick Member
    edited February 2014
    Perhaps they are referring to DHAA: http://en.wikipedia.org/wiki/Dehydroascorbic_acid

    We run an assay that requires reaction with DL homocysteine to reduce the DHAA to ascorbic acid.

    Free ascorbic acid and "total Vitamin C" can be two different measures, especially if the source is a plant extract.
  • BobzchemistBobzchemist Member, PCF student
    If it's that hard to assay the Vitamin C, how could it possibly have any effect on skin?
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
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