Home Cosmetic Science Talk Formulating Alcohol Denatured 40%

  • Alcohol Denatured 40%

    Posted by natchemist on October 17, 2014 at 11:58 pm

    Quick question…

    Why this ingredient label has a percentage next to the INCI name for alcohol ?
    Active Ingredients: Salicylic Acid (2%) (Acne Treatment)
    Inactive Ingredients: Water, Alcohol Denatured (40%), Butylene Glycol, PPG 5 Ceteth 20…….
    Chemist79 replied 10 years, 2 months ago 5 Members · 8 Replies
  • 8 Replies
  • Chemist77

    Member
    October 18, 2014 at 12:58 am

    Quick reply

    to emphasize the absence of preservative if it has been omitted because I suppose (and please mentors correct me if I am wrong) <30% ethanol eliminates the need of preservative, secondly to show that it is 40% ethanol and has to be used accordingly on the skin type. Last but not the least, maybe to emphasize that since it >60% it cannot be used as a sanitizer.

  • nasrins

    Member
    October 18, 2014 at 2:17 am

    alcohol increases penetration of some actives like whitening agents, but with destroying the barrier layer on skin, so in high percentage it damages substances which keeps ur skin healthy and overall it dries the skin…but the qustion here is that why should we used denatured form?or is there any problem if we use not denatured one?

  • Chemist77

    Member
    October 18, 2014 at 2:33 am

    Denatured is generally used to avoid the abuse of the material, there is no other reason I suppose for this. Absolute alcohol is generally used for pharma and to some extent for OTC products.
    In the above case it is there for one more very important reason and that is to aid in the solubilization of Salicylic acid which has a very low aqueous solubility.

  • nasrins

    Member
    October 18, 2014 at 3:04 am

    U mean alcohol( not denatured) doesnt solubilize salysilic acid? I dont think so…denatured makes it unfit for consumption but why is so important in cosmetics I dont know

  • Chemist77

    Member
    October 18, 2014 at 3:24 am

    Read carefully what I wrote, nowhere have I mentioned that alcohol absolute or denatured would affect the solubility of salicylic acid. But the presence of water FOR WHICH I MENTIONED AQUEOUS would definitely retard the solubility and hence ethanol has been used.
    Hope that is pretty plain to understand now.

  • Chemist77

    Member
    October 18, 2014 at 5:02 am

    I wrote the word ‘abuse’ so that the humans cannot consume it after buying it for other reasons. This is the reason why denatured alcohol is used, although in many countries I have seen absolute too being sold but then the regulations are strict to the last drop of the material. 

    In fact many countries have restrictions for precursor solvents too like acetone and you have to furnish all the info re it’s use. 
  • belassi

    Member
    October 18, 2014 at 3:27 pm

    Here in Mexico I can buy any quantity I want of pretty much anything, including pure ethanol. I suppose people don’t drink it because in the supermarkets one can buy industrial alcohol disguised as a low-quality spirit for next to nothing. I have to say, that 40% alcohol is not something I would ever sell, or put on my skin! 

  • Chemist79

    Member
    October 19, 2014 at 4:53 pm

    Not sure which region you are in but from an EU perspective it looks like either biocidal or medicinal labelling rather than a cosmetic.

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