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Electrolyte free chelators
Hi all,
I would appreciate some suggestions for commonly available chelating agents that work well with Aristoflex AVC, preferably a strong chelator that is comparable to EDTA.
So far I’ve only come across citric acid (weak chelator I believe) and gluconolactone. Has anyone had experience using gluconolactone as a chelator? What was your usage rate?
Thanks in advance!
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11 Replies
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I have never heard of Aristo AVC being SO electrolyte intolerant that it could not handle .1 or .2% EDTA. There are many formulas with that combo. (Granted I use GLDA….so maybe I don’t know.)
The intolerance is immediately visible…. Simply mix the formula measurements of EDTA, H2O and Aristoflex….if it gels….they are fine.
Aloha.
My fav chelator…. GLDA. (Not inferring it is better than King EDTA.)
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Graillotion said:I have never heard of Aristo AVC being SO electrolyte intolerant that it could not handle .1 or .2% EDTA. There are many formulas with that combo. (Granted I use GLDA….so maybe I don’t know.)The intolerance is immediately visible…. Simply mix the formula measurements of EDTA, H2O and Aristoflex….if it gels….they are fine.
Aloha.
My fav chelator…. GLDA. (Not inferring it is better than King EDTA.)
Thanks for the suggestion and insights. I thought electrolyte instability might be a gradual process (loss of viscosity over time). I’ll test with 0.2% EDTA in my final product and see if there is any noticeable effect on the texture.
Sadly, GLDA is not available where I live, but I’ll keep an eye out
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Phytic acid
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@PhilGeis Isn’t phytic acid the worst of them all? No other chelate can have that many negative charges…As an educated guess, caprylhydroxamic acid would be better suited because it does form fairly stable complexes with metals but isn’t deprotonated to any significant level at a pH usually used in cosmetics (except soap). Personally, I wouldn’t bet on that compound. Kojic acid goes in the same direction…Another more potent hydroxamate, though with one positive charge, would be deferoxamin LoL. Joke aside, some polyphenols complex/chelate metals, though mostly trivalent ones (Al3+ is of no concern and Fe3+ does not exist in a cosmetic which contains antioxidants) and/or in alkaline conditions. Copper could be complexed with thiol ligands but common ones such as penicillamine are also electrolytes. On the fancy side of things, Salen ligands and similar would be very good non-electrolyte chealtes… though they are not approved for cosmetic use. -
@Pharma
I’ve had some luck with phytate.
Hydroxamates are good for fungi - not for pseudomonads. The best known are pyrithiones - Zn (ZPT) and Na. -
@PhilGeis Good to know. Maybe it’s because the negative charges don’t really count although it has a very high calculated ‘salt index’. Theory meets practice, in cosmetics that’s every time a surprise!I still wonder how exactly caprylhydroxamate inhibits microbes and why it targets fungi more than bacteria???I haven’t thought of pyrithione, a hydroxamate and a thiol in one small cosmetically approved molecule… good one 🙂 !
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@Pharma
My (just a ) guess was that pseudomonad siderophores have a greater affinity for Fe, Mg than hydoxamates - cap, ZPT, NaPT.
ZPT is used in Head & Shoulders - as a raw material, it’s supplied as a ~26% saturated slurry that comes contaminated with pseudomonads unless preserved. -
@ketchito “pseudomonad siderophores have a greater affinity for Fe, Mg than hydoxamates - cap, ZPT, NaPT.”
Does this sentence mean pseudomonad can consume Fe & Mg even after they are chelated by caprylhydroxamic acid or it means something else? -
Siderophores are sometimes hydroxamates but all are very good Fe3+ chelates, thousands times better than pyrithione. With iron 3+, they form one of the strongest non-covalent interactions known to mankind. The only biological means to get iron out of the complex is either by metabolising the siderophore molecule or, more easily, by reducing iron to its 2+ state which binds a lot less tightly.I don’t know whether this, a different metabolism or anything else is what makes them resistant to hydroxamates.
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Abdullah said:@ketchito “pseudomonad siderophores have a greater affinity for Fe, Mg than hydoxamates - cap, ZPT, NaPT.”
Does this sentence mean pseudomonad can consume Fe & Mg even after they are chelated by caprylhydroxamic acid or it means something else?@Abdullah You might want to read this:
Wherein, caprylhydroxamic acid (CHA) adopts this content energy potent mould fungus inhibition—growth of Aspergillus niger (A.Niger), and antibacterial principle: CHA is to Fe 2+And Fe 3+The efficient selective chelation is arranged, in the iron ion constrained environment, the growth restriction of mycete; Ferrum is the key element of growth of microorganism, and Microbiological release chelating agen (siderophores) is caught Fe from environment 3+And it is converted into Fe 2+CHA chelating Fe 3+Stability constant high, can prevent that mycete (A.Niger) from obtaining ferrum element; And it is still effective when pH value is neutral, is antibacterial desirable organic acid. (ref.: https://patents.google.com/patent/CN102920612A/en)
Caprylhydroxamic acid would compete with sidophores molecules to bind available Fe ions (same as brides compete for the last cheap nice dress during black friday). As @Pharma mentioned, sidophore binding with Fe ions is better when they are in the Fe3+ state. -
@ketchito this patent page is in English but when i download it, the language changes to Chinese. Is there any way to download it in English?
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