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Preservative lexguard HPO
Hi,
kindly asking for opinions regarding this preservative efficacy boosted with some EDTA, 2% glycols and pump containers. Composition is 45% caprylyl glycol, 30% phenoxyethanol and 10% hexylene glycol.
It is said to be effective in water only products at 1%, an addition of 0,3% of glyceryl caprylate is highly recommended in lotions.
Thanks in advance
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4 Replies
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Glycols and phenoxy are weak vs fungi.
Highly recommended? Maybe the supplier but doubt anyone familiar with preservation would recommend glycerol caprylate
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I appreciate your expert input. I will add some sodium benzoate. Whenever I add some sodium benzoate I do calculations doing the Henderson–Hasselbalch equation. I have read in this group before that in order for sodium benzoate to be effective there must be 0,1% in protonated form. Is that correct? Based on my calculations 0,25% is the needed amount at pH 4.5.
Thanks a lot!
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I understand and don’t find that so useful. We’re working in dynamics of formulas, microbes and consumer use. There is some degree of consistency/predictability and it more Edisonian than formulaic - derives from efficacy in formulas in use. Most folks here don’t have the luxury of on-demand validated challenge testing and post consumer use survey so they’re best advised to reapply the basic stuff within identified safe in use ranges.
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So you don’t think I’m just blowing you off on this, here’s an example.
Challenge test revealed that benzoate consistently added a lot for preservation of surfactant products, esp. at pH (7.5) well above benzoic acid pKa. We’ve known this for many years before it was described and technically addressed in the literature.
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