Home Cosmetic Science Talk Formulating New preservative question

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  • New preservative question

    Posted by Margaret on January 12, 2023 at 5:29 am

    There is a new preservative available to the DIYer called TRISTAT PC 90.
    It is 90% phenoxyethanol & 10% capryly glycol

    Currently I use the following in my skin creams for preservatives (plus hurdle ingredients like 6% propylene glycol):

    0.3% Phenoxyethanol
    0.5% Germall + 

    Could I substitute the 0.3% TRISTAT for 0.3% Phenoxyethanol (PLUS the 0.5% Germall +)   and  expect the same level of preservation? NOTHING else would be different about the skin cream, just possibly using the Tristat preservative.

    Thank you for any comments!

    PhilGeis replied 1 year, 10 months ago 4 Members · 13 Replies
  • 13 Replies
  • Graillotion

    Member
    January 12, 2023 at 5:57 am

    Margaret said:

    There is a new preservative available to the DIYer called TRISTAT PC 90.
    It is 90% phenoxyethanol & 10% capryly glycol

    This is new? :)  It was called Optiphen….forever.  Nothing like dusting off a classic, and putting a new bow on it. :)  (I guess that is what marketing is!)

    .3% to .3%…would not be an identical match…due to the Optiphen being at a 90% ratio of phenoxy.

    FYI….carbon chain length of PG…is pretty short… I will speculate… 2% of Pentylene glycol will do as good a job….and feel better. :)  The effectiveness increase with carbon chain length.

  • Abdullah

    Member
    January 12, 2023 at 12:14 pm

    Yes 
    No problem 

  • PhilGeis

    Member
    January 12, 2023 at 12:41 pm

    As Graillotion said, the “new preservative” is not novel -  a marketing combination and nothing special.  You need something for fungi.

    Your current preservative is overkill.  Drop the phenoxy entirely, Germall+ should ~3000 ppm.  A chlelar (EDTA is appropriate).

  • Margaret

    Member
    January 12, 2023 at 3:06 pm

    O.K. thanks all you fine people!

     I had NOT realized this Tristat & Optiphen are different combinations of phenoxyethanol & capryly glycol. 

      I have been using the phenoxyethanol with the Germall +  only the last 1 1/2 years approx.  because it’s supposed to be slightly volatile from what I read on a real cosmetic chemist’s blog/web-site, so I figured I’d add that to the CREAM since fingers go into the product.  I’m happy to read I can just go back to Germall + only. Woopee  :)!

    I use sodium phytate at 0.3%. Once that’s gone I’ll go back to the EDTA at 0.2%.

  • Graillotion

    Member
    January 12, 2023 at 7:23 pm

    Margaret said:

    O.K. thanks all you fine people!

     I had NOT realized this Tristat & Optiphen are different combinations of phenoxyethanol & capryly glycol. 

      I have been using the phenoxyethanol with the Germall +  only the last 1 1/2 years approx.  because it’s supposed to be slightly volatile from what I read on a real cosmetic chemist’s blog/web-site, so I figured I’d add that to the CREAM since fingers go into the product.  

    I use sodium phytate at 0.3%. Once that’s gone I’ll go back to the EDTA at 0.2%.

    ….Not different combinations….the EXACT same combo. :)

     I think you have read some terms…and mistaken some similar sounding terms.

    What you want on the glycol…is ‘Pentylene’ glycol.

    Pentylene Glycol (formulatorsampleshop.com)

    What you want as the head space preservative….is: ‘Phenethyl’ alcohol, not Phenoxy!

    Perfumers Apprentice - Phenyl Ethyl Alcohol

    (Hehehehe….sure sounds like you were trying to follow my protocols…I have posted on other pages. :) )

    And Yes….your current system was rather redundant, and did not achieve you desired effect.  Switching to Phenyl Ethyl…will also be redundant, but will give you the desired ‘head space’ result you are looking for.

    Aloha.

  • Graillotion

    Member
    January 12, 2023 at 7:48 pm

    @Margaret I would be remiss to not say…. Phenyl ethyl alcohol…has a pronounced ‘rose’ scent.

  • PhilGeis

    Member
    January 12, 2023 at 8:08 pm

    Phenyl ethyl is not so good vs. Gram positives.  For headspace - IF it volatilizes from your product at level - it might inhibit Gram neg’s and fungi.

    https://microbeonline.com/phenylethyl-alcohol-agar-pea-principle-composition-and-preparation/

  • Graillotion

    Member
    January 12, 2023 at 8:17 pm

    PhilGeis said:

    Phenyl ethyl is not so good vs. Gram positives.  For headspace - IF it volatilizes from your product at level - it might inhibit Gram neg’s and fungi.

    https://microbeonline.com/phenylethyl-alcohol-agar-pea-principle-composition-and-preparation/

    What do you think of O-Cymen-5-ol as strictly a head space preservative (add-on)…. I guess in comparison to PEA?  @PhilGeis  I always have a big pile of that on hand.

  • PhilGeis

    Member
    January 13, 2023 at 12:51 pm

    O-Cymen-5-ol vapor pressure is a bit < PEA’s.  Don’t know if either would be effective for headspace from cosmetic matrix
    Are you sure you need headspace preservation?

  • Graillotion

    Member
    January 13, 2023 at 8:19 pm

    PhilGeis said:

    O-Cymen-5-ol vapor pressure is a bit < PEA’s.  Don’t know if either would be effective for headspace from cosmetic matrix
    Are you sure you need headspace preservation?

    I do have two products in jars that consumer touches….so…. Yes! :) (Especially since I don’t use P’s and F’s.)

  • PhilGeis

    Member
    January 13, 2023 at 8:35 pm

    @Graillotion
    Consumer touches?  Can you explain?
    Have you seen contamination on inner package surfaces?

  • Graillotion

    Member
    January 13, 2023 at 8:47 pm

    PhilGeis said:

    @Graillotion
    Consumer touches?  Can you explain?
    Have you seen contamination on inner package surfaces?

    Consumer extracts product with finger. 

    No…But I already use PEA in the product…and jump through all the preservation hoops…plus some extra ones.  :D

    Product below…. finger extraction of product.

  • PhilGeis

    Member
    January 14, 2023 at 12:13 pm

    @Graillotion
    I think you’re ok without an attempt at head space protection.  Open pots have been around for around a century.  My experience - we didn’t worry about growth on inner package surface.  

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