Antimicrobial activity of organic acids & non-traditional preservatives

Does anyone have a good resource for specific antimicrobial activities of individual preservatives, mainly organic acids and non-traditional preservative? I’m trying to make my own broad spectrum (or close to broad spectrum) preservative combination, but I’m having a tough time finding what preservatives are affective against what microbes (gram pos, neg, yeast, mold, etc.). I know I will eventually have to challenge test, but it would be nice to start with a theoretical broad spectrum combo first.

I’m currently looking at dehydroacetic acid, dechlorobenzyl alcohol, caprylyl glycol, glyceryl caprylate, chlorphenesin, hexamidine diisethionate, phenethyl alcohol, etc.

 

Parameters: mainly lotions, ph 4-5, sensitive skin, hypoallergenic, non-Parabens, non-Formaldehyde Donors, non-Isothiazolinones, will add EDTA, glycerin, antioxidant if need be

Comments

  • JvicJvic Member
    I haven't found any conclusive sources yet, but I thought I'd post some helpful links I've found for anyone who is interested in learning the specific antimicrobial activity of preservatives:

    Nice search tool (only the companies preservative products are included): 
    http://www.lonza.com/products-services/consumer-care/personal-care/formulaprotect/formula-protect.aspx

    Interesting experiment with natural preservatives (note: this is not properly conducted study but helpful to get started): 
    https://thenerdyfarmwife.com/natural-preservatives-for-homemade-lotion-and-cream/

    Excellent Powerpoint Overview:
    http://www.cbinet.com/sites/default/files/files/English_Don_pres.pdf

    Another popular overview (this is all over the internet but important place to start) thanks Makingskincare:
    http://www.makingskincare.com/preservatives/

    List of many preservatives:
    http://www.ashland.com/Ashland/Static/Documents/ASI/Personal%20Care/SkinCare_Preservatives_Brochure.pdf

    I've been able to discern quite a bit of info on antimicrobial activity of individual preservatives from the above material. I'm still looking, if anyone as any other source.
  • PerryPerry Administrator, Professional Chemist
    Great list of links.

    I'm not sure I understand what your question is however.

    You'll find that in the cosmetic industry there are not a lot of compiled resources of data like the one you seem to be implying. This is because topics like preservatives are researched mainly by companies who are looking to use the information to create products (preservatives) to sell. They don't readily share information that would be helpful to competitors.
  • JvicJvic Member
    Thanks Perry. I figured as much since I've been researching the topic for weeks now. I ask the question because I would like to have complete control over what preservative ingredients go into my formula rather than using a commercial, premixed preservative combination. I guess I'll just have to put the pieces together from various sources and challenge test different combinations.
  • MicroformulationMicroformulation Member, Professional Chemist
    Start here. This is a pdf overview of Preservation. It is a few years old so the usage data (most popular preservatives) is dated, but the updated data has been posted on here recently.

    My advice on learning preservatives is to step away from a comapanies listing of preservatives and instead learn the chemical classifications (ex. paraben, organic acid, etc.) and the way to best use them. Then you will see once you select the correct preservative class or group that will work best in your Formulation, you can likely find a matching product from most suppliers.

    Also and lastly, preservation is based upon the characteristics of each Formula, not a one size fits all situation. In addition it is not just a matter of adding a preservative, mixing and being done. Follow the Hurdle Technique as outlined in the presentation. Factors such as the packaging, pH and Manufacturing sanitation have a factor as well. As David Steinberg says often, "The best preservative is good cGMP."


    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. BS.Pharm Albany College of Pharmacy, Union University.
  • JvicJvic Member
    @Microformulation ;This is a great presentation and pretty much what I was looking for. I actually was only looking for antimicrobial activity of preservative classes so that I had a starting point. So, this is a perfect source. Yes, I will be taking into account pH, packaging material, available water, pump bottle, good cGMP, co-preservative and chelators, etc. Hurdle Technique is a nice summary/outline to follow. Thanks, this will be very helpful.
  • BobzchemistBobzchemist Member, PCF student
    To add to Perry's point, a lot of this information is also distributed in professional seminars or masters-level courses. The people who give the seminars certainly don't want the information freely out on the web that they present for $1,000 to $2,000 per person - and the people who take the seminars/courses have no incentive to post it either.
    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."
  • MicroformulationMicroformulation Member, Professional Chemist
    Remember that Free water (Aw) makes for a cool theory. However, it can not be calculated. It must be measured, both in R&D and also in Production. The equipment is specialized. Using Aw is one of the tricks of the "preservative free" market. But again, lacking the equipment to properly measure this value, it simply becomes a part of the overall Hurdle process, not a standalone.

    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. BS.Pharm Albany College of Pharmacy, Union University.
  • JvicJvic Member
    Is it even reasonable to get Aw down to 0.7 (or even 0.92) in a emulsion like a lotion and still have an aesthetically pleasing product? So, I guess my question is it worth measuring the Aw to try to get a "preservative free" claim? It seems like it would make more sense to to add glycols and polyols to the point where it's aesthetically acceptable as part of the Hurdle process?
  • JvicJvic Member
    Interesting article on that subject 
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