Phenoxyethanol replaced by phenethyl alcohol?

DoreenDoreen Member
edited August 3 in Formulating
Hi,

I have experienced some disadvantages of the use of phenoxyethanol and I wonder if phenethyl alcohol has any substantial advantages over phenoxyethanol in some ways, or if it is of no use to replace one for the other or if they’re even comparable at all regarding antibacterial properties.
I can imagine phenoxyethanol having a broader antibacterial spectrum as it’s (more often) purposely used for this reason, but I'm not sure.
To be honest I haven’t really been diving into the matter, as I have to place an order rather soon and I saw that the supplier stocks phenethyl alcohol too.

Solubility of phenoxyethanol in water is 0,5 gr/100 ml. Solubility of phenethyl alcohol in water is 2 ml/100 ml, the relative density is 1,02 gr/cm3 (wikipedia), so a solubility of 2,04% as opposed to 0,5% already seems at least one advantage.
However I don’t know the recommended or maximal level when used as preservative, because the European Union hasn’t  designated the substance for the use of preservation, so a limit hasn’t been set. Neither do I know the minimal inhibitory concentration.

My question to you all is: what are your experiences with phenethyl alcohol as antimicrobial. Do you know the recommended usage level. Can it cause comparable stability issues to phenoxyethanol, is it easier to work with and are there other things to keep in mind.

N.B. I will be pairing it up with methyl- and propyl paraben.

Thanks in advance!

Edited the the substance name as the name phenethyl alcohol is more used than its synonym phenylethyl alcohol.

Comments

  • MarkBroussardMarkBroussard Member, Professional Chemist
    @Doreen:

    Phenthyl Alcohol is an excellent addition as a preservative ingredients and you can use it as a direct substitute for EHG.  It is particularly strong against yeast/mold.  Your best approach is to make a concoction of Phenethyl Alcohol (50%) and Propanediol or Pentylene Glycol (50%) to enhance solubility.  Drop this mixture in at 1% to 1.5%.

    When I have trouble with mold, Phenethyl Alcohol is my go to ingredient, hands-down.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • DoreenDoreen Member
    @MarkBroussard
    Thanks for replying so quickly!
    I automatically assumed it's action would be mainly antibacterial, but it's nice to see that it is particularly active against yeast and mold.
    No need to pair it up with parabens then.
  • PharmaPharma Member, Pharmacist
    Phenethyl alcohol is particularly weak against gram-positive bacteria but being somewhat volatile makes it a good headspace preservative (better than phenoxyethanol). Advantage/drawback might be its rose scent. It can be irritating for the eyes and might taste unpleasant but I have no personal experience in that regard (besides, many cosmetic ingredients do that in concentrated form).
    It's recommended to be use in blends for example with wetting agents like glyceryl caprylate or caprylyl glycol (or such that @MarkBroussard already mentioned).
    If you want some reading: 1, 2, 3
    If/when I have to restock preservatives I am considering to give it a try.
  • MarkBroussardMarkBroussard Member, Professional Chemist
    Phenylpropanol is another option that is similar, but has a reduced rose fragrance ... of the two, I prefer Phenethyl Alcohol.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • DoreenDoreen Member
    @Pharma @MarkBroussard
    Thanks guys! 
    If I use preservatives like Dermosoft 1388 or Euxyl PE 9010 I always pair it up with glyceryl caprylate or caprylyl glycol at 0.3% (GMCY and Octiol: the German DIY supplier I order from stocks about everything from Dr. Straetmans!)
    Just like you, I always perform the hurdle technique. When I use e.g. Germaben II or Liquid Germall Plus just not so extensive. Although no matter the type of preservative, I always work accordingly to GMP rules for as much that is possible in an amateur home 'lab' (aka our den).

    I'm not particularly fond of rose scents, but I guess at a level of 0.5-0.75%, as Mark mentions, it won't pose much of a problem.

    I'll give the links a thorough read, Pharma. Thanks a lot!
  • MarkBroussardMarkBroussard Member, Professional Chemist
    Dermosoft 1388 + Phenethyl Alcohol (Dermosoft PEA) is a nice, effective combination.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • DoreenDoreen Member
    @MarkBroussard
    Thanks for the tip! :+1:
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