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Depilatory
Hi everyone!I am working on depilatory formulation. All the formulation I found were mentioning base viz NaOH, Ca(OH)2, etc. I know that this product should be at high pH, but how high exactly for it to be effective? and what does actually the base do here? I ever read it somewhere that high alkalinity helps soften the keratin (whether it is on skin or on the hair itself) so that they are easily removed. Is that really the case and mechanism of action?
Please let me know if you have any knowledge on this pal and TIA!oh anyway im using ammonium mercaptoacetate for the active ingredient -
2 Replies
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What you are noting is the free alkali hydroxide species used to form water-soluble thioglycolate salts with 80% thio (aka mercaptoacetic) acid. We made thioglycolates in situ with these, balancing the calcium hydroxide (add first!) with some sodium thio salt and free alkali. Calcium thio is the safer keratoyltic if I remember - and its been a long while - while sodium hydroxide merely boosts the pH to 12.5 necessary to work fast. Similar to activity of alpha/beta hydroxyacids on the low end of the pH scale, alkali thioglycolates work just as well at pH9 but a LOT SLOWER and that gives them more time to irritate your skin, thus the pH boost. 15 minutes contact time and wipe away the hair.
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Thank you so much fro the explanation, it is very helpful!
chemicalmatt said:What you are noting is the free alkali hydroxide species used to form water-soluble thioglycolate salts with 80% thio (aka mercaptoacetic) acid. We made thioglycolates in situ with these, balancing the calcium hydroxide (add first!) with some sodium thio salt and free alkali. Calcium thio is the safer keratoyltic if I remember - and its been a long while - while sodium hydroxide merely boosts the pH to 12.5 necessary to work fast. Similar to activity of alpha/beta hydroxyacids on the low end of the pH scale, alkali thioglycolates work just as well at pH9 but a LOT SLOWER and that gives them more time to irritate your skin, thus the pH boost. 15 minutes contact time and wipe away the hair.
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