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Inactivation of Preservatives
Is the inactivation of 2-phenoxyethanol by non-ionic surfactants such as polysorbate 20 or PEG-100 Stearate a very large concern even if those surfactants are used at 1.5% of a face cream formula? Thinking of using an anionic-surfactant based formula instead.
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14 Replies
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Phenoxyethanol is not deactivated by nonionic surfactants. Most overlooked property of phenoxyethanol is that it does not act well alone as a preservative. It is most effective “cooperating” with polyols, parabens, phenolics, PCMX, etc.
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I read on this link that there is some inactivation. Is this false? https://www.americanpharmaceuticalreview.com/Featured-Articles/38885-Antimicrobial-Preservatives-Part-Two-Choosing-a-Preservative/
”benzyl alcohol [16], 2-phenoxyethanol [42], 4-chloroxylenol [20] and m-cresol [25] should not be formulated with non-ionic surfactants. Chlorobutanol [43] and 2-phenylethanol [37] are adversely affected by the presence of non-ionic surfactants, e.g. polysorbate 80.”
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Does anyone know?
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I’ve personally never experienced this problem.
I’ve also never heard of phenoxyethanol being deactivated by non-ionic surfactants before. -
natzam44 said:I’ve personally never experienced this problem.
I’ve also never heard of phenoxyethanol being deactivated by non-ionic surfactants before.I should add that phenoxyethanol can be weakened by large amounts of ethoxylated surfactants but this is usually a non-issue.
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I was quite puzzled because the link I shared seems very much like a reputable source yet they say that non-ionics can inactivate phenoxyethanol… maybe % of the non-ionic surfactants is major here.
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Parabens can get deactivated by non-ionics, especially polysorbate 80 (and to a lesser extent 20 and 60). I’ve never heard this about phenoxyethanol.
Here some information from a book called Surfactants in Cosmetics by Rieger/Rhein:
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A very interesting read there Doreen. Thank you. I f you check out the website url that I linked, you will see that phenoxyethanol seems to have issues with non-ionic surfactants too. I think I may stop using Arlacel 165 and switch over to glyceryl stearate and sodium stearoyl glutamate.
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I know that information that phenoxy is deactivated by highly ethoxylated compounds comes from some crafter suppliers including lotoincrafter https://lotioncrafter.com/products/phenoxyethanol?_pos=1&_sid=6197b176d&_ss=r
Still don’t know whether it’s true or they just misunderstood something. -
@LuisJavier
You’re welcome! And thanks for the link, I will have a thorough read as soon as I have time.
@ngarayeva001
Interesting. Now I must say that Lotioncrafter doesn’t always provide 100% accurate information, but this indeed is puzzling. -
You’re welcome
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It seems that lotioncrafter maintains that even sodium benzoate is inactivated by non ionic surfactants. https://lotioncrafter.com/products/sodium-benzoate
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The effect is not limited to a distinct chemical structure but mostly to a lipophilic, non-ionic structure (of preservative and emulsifier), surfactant-like behaviour, and preservative/emulsifier interactions (which is a result of the former two properties; like attracts like). I cite above citation by @Doreen: “…alcohol, phenyl alcohol, and phenyl ethyl alcohol…/…lipophilic preservatives (e.g. paraben esters)…”.Most publications as well as most formulations of interest (obviously, pharmaceuticals are studied in more detail than DIY stuff) are based on traditional preservatives of which parabens stand out as particularly lipophilic, non-ionic, and surface-active. Alternative preservatives such as phenethyl alcohol, caprylyl glycol, GMCY, or 1,2-hexanediol etc. show similar lipophilic and surface-active properties which makes them prone to inactivation phenomena. Their yet rather scarce use (in science) is the one reason why there are also only few publications and investigations available showing this inactivation (and any other effect, too). -
All of the above is really making me desire to skip the peg-100 stearate and replace it with sodium stearoyl glutamate.
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