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Preservative quantity suggestion for 0.5% allantoin+0.25% tetrasodium EDTA solution
I am making a simple solution of 0.5% allantoin + 0.25% tetrasodium EDTA in water.
pH adjusted to 5-5.5 with citric acid.
Packaging is in 220ml flip top cap.What amount of phenoxyethanol+ caprylhydroxamic acid do you recommend as preservative for this solution?
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11 Replies
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Try 0.3/0.5. Have seen stability issues with EDTA and another hydroxamic acid Zn complex ZPT . Don’t know if efficacy impacted. Suppose AET will reveal.
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@PhilGeis thanks
1. Do you mean 0.3% phenoxyethanol and 0.5% caprylhydroxamic acid?
2. Is this stability issue something we can see and notice by simple observation of product?
I am using 0.6% phenoxyethanol+ 0.15% caprylhydroxamic acid+ 0.2% tetrasodium EDTA at pH 5.1 in anionic emulsion and haven’t noticed any problem or instability in samples from 6 months ago. -
no - 0.5% phenoxy/0.3% cap hydroxamic acid. Be aware - this does leave a paper weakness vs Gram positive bacteria.
Prob not see - as in color or phase stability - but in AET testing.
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@PhilGeis would increasing the amount of phenoxyethanol or adding 0.3% glyceryl Caprylate cover Gram positive bacteria?
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not much - but test the product. Gram negatives are you biggest worry.
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PhilGeis said:not much - but test the product. Gram negatives are you biggest worry.
Thanks
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Can you describe packaging? Gram + (staph) is largely an in-use risk.
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PhilGeis said:Can you describe packaging? Gram + (staph) is largely an in-use risk.
It is 220ml HDPE bottle with flip top cap.
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@PhilGeis gentle reminder
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Prob ok.
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PhilGeis said:Prob ok.
Thanks
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