Home Cosmetic Science Talk Formulating Natural presevation

  • Natural presevation

    Posted by Lisa18 on August 18, 2018 at 9:54 am

    Goodmorning everyone.
    I’m working with a preservative system (for me new) in biological formulations. I tested the mixture: benzyl alcohol, dehydroacetic acid and benzoic acid at 1% with challenge test and occlusive patch tests at 48 h and the products were non-irritating.does anyone have experience with this preservative system? have you had skin sensitization reactions in the finished product? Thanks in advance! lisa - clear

    Lisa18 replied 5 years, 7 months ago 4 Members · 9 Replies
  • 9 Replies
  • Sibech

    Member
    August 18, 2018 at 10:25 am
    I do not have experience with that particular system (and the proportions of the various compounds have not been mentioned.
    I can hover tell you that Benzyl alcohol is a well-known allergen (and you cannot claim “fragrance-free” with it) and will likely cause some level of sensitization in a subset of consumers.
    Also, about 0.2% of the population will likely display irritant contact dermatitis with benzoic acid (concentration dependent though).
  • Lisa18

    Member
    August 18, 2018 at 11:25 am

    thanks Siber! the preservative system is composed as follows: about 80% benzyl alcohol, about 12% benzoic acid and about 8% dehydroacetic acid. the% of benzyl alcohol in the finished product is around 0.8%. We have carried out patch tests on the finished product and they are not irritating. What other tests can we carry out for the safety of the product? with the preservatives allowed by the Cosmos specification there are not many choices unfortunately ..
    thank you so much
    lisa

  • oldperry

    Member
    August 20, 2018 at 1:33 pm

    Well, you should also do a preservative efficacy test (PET)

  • doctorbrenda

    Member
    August 20, 2018 at 2:29 pm

    Lisa,
    The preservation efficacy and potential for allergen/sensitizing reactions are two separate things.  Efficacy tests are much easier to provide accurate results for because the testing methods are pretty straight forward, with less margin for error.  The results of the latter will be quite different (more variable data) depending on how the patch tests were done.  Did you do these on animal or human subjects?

  • Sibech

    Member
    August 20, 2018 at 3:35 pm

    I might have misunderstood but in general I hear preservation efficacy test as a challenge test which was mentioned in the original question.

  • Lisa18

    Member
    August 20, 2018 at 6:40 pm

    Hello Doctorbrenda,

    we conducted occlusive patch tests on human skin. the application lasted 48 hours and were non Irritant. To test the effectiveness of the preservation system we performed a challenge test
  • Lisa18

    Member
    August 20, 2018 at 7:08 pm

    Thanks doctor Brenda. I have performed occlusive Patch test on human skin (48 h application).To test preservative efficacy we performed challenge test.

  • doctorbrenda

    Member
    August 20, 2018 at 10:01 pm

    That’s good, because it is more valuable.  Besides the fact that most of the companies that have third-party sources performing their cosmetic testing employ unskilled workers, little or no education/training, and there is little or no supervision to ensure the protocols are performed accurately… the biggest issue is that researchers with real science degrees are inclined to agree that there is no evidence that animal experiment data can be extrapolated to predict results in human subjects, nor provide any useful information to construct hypothesis testing in the future.

  • Lisa18

    Member
    August 21, 2018 at 6:32 am

    Thank you for your comments. do you believe that the results of a 48 h occlusive patch test are quite exhaustive?

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