Home Cosmetic Science Talk Formulating Salicylic acid effective in anhydrous formulas? (since oils don’t have pH..)

  • Salicylic acid effective in anhydrous formulas? (since oils don’t have pH..)

    Posted by Zink on March 24, 2014 at 9:25 pm

    SA’s functionality as an acid is very pH dependent, being a good H donor in a narrow range up to about 3.5 or 4. pH 3 is ideal. Now how will salicylic acid work in a anhydrous ointment?

    Zink replied 9 years, 8 months ago 4 Members · 5 Replies
  • 5 Replies
  • chemicalmatt

    March 25, 2014 at 5:31 pm

    It won’t.

  • cosmochem

    March 25, 2014 at 6:40 pm

    What are you using it for? If it is for Acne, may be you can try Benzoyl peroxide.

  • Zink

    March 25, 2014 at 9:30 pm

    Chemicalmatt. There’s more to it that acidity I believe, so It could work great.

  • Bobzchemist

    March 26, 2014 at 10:14 am

    The answer, like so many answers in cosmetic chemistry, is “it depends”. 

    If the SA in the anhydrous formula is able to penetrate into at least some of the stratum corneum, it may work well enough to provide exfoliation. The exfoliating effect of SA may not be dependent on it’s pH, either.
  • Zink

    March 27, 2014 at 2:10 am

    Wiki could give some hints, not sure which would apply for topical use: 

    Salicylic acid has been shown to work through several different pathways. It produces its anti-inflammatory effects via suppressing the activity of cyclooxygenase (COX), an enzyme that is responsible for the production of pro-inflammatory mediators such as the prostaglandins. It does this not by direct inhibition of COX like most other non-steroidal anti-inflammatory drugs(NSAIDs) but instead by suppression of the expression of the enzyme (via a yet-unelucidated mechanism).[23] Salicylic acid has also been shown to activate adenosine monophosphate-activated protein kinase (AMPK), and it is thought that this action may play a role in the anticancer effects of the compound and its prodrugs aspirin and salsalate. In addition, the antidiabeticeffects of salicylic acid are likely mediated by AMPK activation primarily through allosteric conformational change that increases levels of phosphorylation etc etc 
    Anyways, I guess I just have to test it.

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