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Help me make sense of this: effective and compatible over a pH range of 3 – 8.
As you know…I help out on beginner forums. Where preservative selection is done by polling other beginners. So here is the INCI of one they love to flock to:
Benzyl Alcohol (and) Salicylic Acid (and) Glycerin (and) Sorbic Acid
So… I see an alcohol…and two acids. All is somewhat good to this point. But …. What about that title… Mfg says this magic elixer works at a pH range up to 8! Now memba…most of these folks that have flocked to this, have never heard of a chelate….and they have piled more bug food into the formula than a F-bomb plus parabens could handle. That … and the pH…is just gonna be native. Heck…what good would adding lactic acid do? ????
So can one of you chemistry whiz’s tell me how those last two ingredients are gonna help when the pH gets much above 6?
I suspect the ‘eager to sell product’ mfg…is of the attitude…that JUST the Benzyl alcohol will carry the load in the 6-8 pH window? Am I wrong? Will these neutralized acids…have some magic residual activity I am just to dull to understand?
The mommies and I…look forward to your answer.
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21 Replies
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BTW… I do not use this as a preservation system…just trying to help those that do. 🙂
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well. Most of the effectiveness at a ph between 7-8 comes from the benzyl Alcohol.
The Sorbic Acid will lose its effectiveness around a ph of 7 before that point around a ph of 6 10-20 % of the Sorbic acid will be in acid form and therefore still active. at a ph of 4.5, it would be 80 %
For the Salicylic Acid, it is similar I think if I remember correctly the active point for the neutralization of Salicylic acid is around 6.5 . above that, the active concentration will be very low.
I guess the idea of the Product is depending on the Product you want to use one of the two will be active and therefore eliminate the bacteria and Molte. I personally would not consider using something like that it is better to have a conservation system that works exactly for your parameters because it makes the efficiency so much better.
I think from this conservation system you have to use at least 1% to be sure it works in all mediums well enough and probably you need to use another conservation medium to help like Pentylenglycol or something similar with 3 -5 %. above ph 6.5 two parts of the system will be useless so I can use Benzylalcohol in a similar amount and have the same effect without building up the salt level in my Formulation.
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I have seen the patent. They use these amounts of glycerin and acids because they can be dissolved in these ratios. Not because they are more effective.
For example if you increase the amount of an acid or don’t use that glycerin the Product would crystalize.
So it is a good idea to use some extra acid with this preservative.
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This is just marketing BS - slightly acid to 8 is cynical marketing at best showing profound ignorance of the objective.
Definitely weak vs Gram negative bacteria, again at any pH.
Do not use this stuff - build a system that should work in context of your product.
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@PhilGeis What would be your favorite “Gram - ” add-on….that would appeal to the ‘natural’ crowd? (I know…probably an oxymoron.)
Seems like a number of combos sold…are a touch weak in this segment. Preferably….don’t answer….phenoxy….hehehhe.
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Aware of nothing for the natural “just stick this in” .
Can construct effective systems that meet “natural” contrivance based on formula and with chelator, glycol (at decent %’s), organic acid, if benzyl alcohol - with benzoic acid, phenoxy (not phenyl), pH control, process and package design. Rarely see evidence of this in most of the clean beauty offerings.
Sal acid has even been used as part but with very narrow, buffered pH range.
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Dr Geis, @PhilGeis I came across this chart, which discusses the efficacy of benzyl alcohol based on pH. Naturally one knows the organic acids want a lower pH…but I had not seen this before. It does not show the rate of fall off…as pH increases. I believe I had read (maybe not true) that as pH rises, Benzyl alcohol is pretty much relegated to Y/M/F activity, and becomes progressively weaker on bacteria as pH rises?
Now the chart does title the category ‘optimal efficacy’…so maybe there is not a lot of ‘fall off’ of efficacy with rise of pH, in relation to Benz alcohol?
Could you elaborate…on the efficacy of Benz alcohol, in relation to this marketing blurb…and protection up to 8!!! We have already established the acids are worth ‘Jack Zero’ (stolen verbage)…. but what is happening to Benzyl…as we slide up the pH scale….to 8?
Thank You. From the grasshopper.
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Gram + and fungi generally ~5 or less. Dave Steinberg liked it up to 7 - for me 7 and broader efficacy (some v. Gram neg) with benzoic acid in surfactants.
What is ref 16?
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Dr Geis, @PhilGeis the reference 16 was this….and I do not have this book:
- E.Cahill, Benzyl Alcohol Monograph in: R.C. Rowe, P.J. Sheskey, P. J. Weller (Eds.), Handbook of Pharmaceutical Excipients, Fifth Edition, Pharmaceutical Press, 2006, pp. 69-71
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Here’s the book https://drive.google.com/file/d/0B8A98zYzLCDRb2xadjU2MnlkQXM/view?resourcekey=0-VOuv7UH-bSJiN_jaQhb3Q\\
says “optimal activity” below 5, little above 8. That’s what I understand. My comment re benzoic acid with surfactants up to 7 is data based.
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Thank you Dr Geis. I guess I have my reading cut out for me…over the next few days. Hopefully it is rainy…in the rain forest. ????
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Have a beer!
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Immortalizing the cell line will eliminate the frequent need to re-establish fresh cultures from specimens. Immortalized cell lines are capable of extended proliferation and should possess similar or identical genotype and phenotype to the parental tissue.
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@PhilGeis please give me your opinion about combination between phenoxyethanol and benzyl alcohol for pH between 5 and seven and is sensicare 1060 Piroctone Olamine (and) Phenoxyethanol (and) Glyceryl Laurate is effective in same range 5_7
Thanks a lot for your precious share
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<div>Do you know the percentage of each ingredient in this blend? </div>
Instead of this you can buy phenoxyethanol and piroctone separately and mix them. This way it will cost much less.
I am doing this one
1% piroctone olamine
5% caprylhydroxamic acid
In phenoxyethanol
@ 1% use it has 100ppm PO and 500ppm CHA + 0.2% EDTA and pH below 5
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Just curious @PhilGeis your thoughts on hydroxamates in cosmetic preservatives? I know our good friend Pharma….could not string enough swear words together in English…to really show his utter displeasure for them… ???? (He always teased me, that I struggled with English as my first language, and as his fifth language, he was much more adept.)
He wrote me a lengthy blurb once…. that disparaged me for life…from using them.
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Hydroxamates are ok versus fungi not Gram negatives
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I was looking more at the aspect….of the human. ????
Would you want it on your skin? (hydroxamates)
Fekher…. the additiion of piroctone olamine should pick up dandruff nicely. ????
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@PhilGeis I did not understand if sensicare c 1060 is effective in pH 5_7 or not?
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Phenoxy+EHG should be ok in that range v Gram negatives - do not trust supplier BS
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