Home Cosmetic Science Talk Formulating Advanced Questions Dissolving Azelaic Acid/Salicylic Acid using Betaine (Bioavailability Impacts?)

  • Dissolving Azelaic Acid/Salicylic Acid using Betaine (Bioavailability Impacts?)

    Posted by ZoeH on November 9, 2022 at 11:23 pm

    Hi, so I am trying to understand the nuances of delivering Azelaic Acid and Salicylic Acid to the skin, in particular for action against acne. I’m curious about if/how lecithin/phospholipids/betaine/glycine/urea could help dissolve and deliver these two acids.

    I have read this forum extensively and I’m still a bit confused. I have heard many mixed opinions about PH of salicylic acid, some people think it’s important and others don’t. I’ve heard that high PH salicylic acid is released more slowly and exfoliates less. 

    “the pH of the preparations only minimally influenced efficacy, local dermatotoxicity was significantly increased at acidic pH. This indicates that the quest to increase the amount of free, non-dissociated SA is, in fact, counterproductive as the more acidic preparations resulted in skin irritation and barrier disruption.” - A study called “Cutaneous bioassay of salicylic acid as a keratolytic”

    I have also heard that because salicylic acid is oil soluble, that is more important for penetration than acidity/amount dissociated.

    As for azelaic acid, azelaic.com recommends delivery using an ‘organogel’ emulsion which is primarily based on lecithin/phospholipids. Would lecithin also work to deliver salicylic acid? Would that have enhanced bioavailability and minimal irritation, as is promised for azelaic acid?

    I’ve read a study that says urea increases solubility of salicylic acid. I also saw someone mention on this forum that urea/betaine helps dissolve allantoin in water. People mention using betaine to dissolve salicylic acid (but then it might form betaine salicylate depending on ph? which is like half as effective as salicylic acid??) Also a product on ulprospector offers a Polyglycerin-6 (and) Azelaic Acid (and) Betaine as a water soluble azelaic acid that won’t crystallize. 

    “Betaine is trimethylglycine which is a zwitterion that can be positively and negatively charged. Likely it is creating a pH environment where the azaelic acid gives up both protons to become negatively charged and therefore water soluble.” - a redditor on r/chemistry

    betaine forms a hydrogen-bonded complex with salicylic acid rather than a salt, which increases its solubility; I’ve formulated with it at pH 3.0-3.5, with a 2:1 molar ratio of betaine to acid and it remains relatively soluble” - Bill_Toge

    I guess zwitterions like betaine/glycine form complexes with azelaic acid/salicylic acid which makes them easily water soluble, but are these complexes making the acids less active/bioavailable when fighting acne? Is there a time release effect? Do they no longer exfoliate?

    Sorry for being all over the place… I just get super confused when I hear conflicting information! I want to know the best way to deliver azelaic acid/salicylic acid to acne-prone skin while minimizing irritation. Thanks for listening to the rant…haha

    ZoeH replied 1 year, 3 months ago 1 Member · 0 Replies
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