Cosmos-approved preservative for clay mask

Hi guys
I’m formulating a. Lay mask containing, honey, clay and glycerin, no water. I tried dermosoft 1388 4%, leucical 3%, and aspen bark 2% all together. It failed the challenge test, any suggestion? I need Cosmos-approved preservative. I really appreciate your help


  • PharmaPharma Member, Pharmacist
    Dermosoft 1388 requires you to lower the pH. Since there is as good as no water present whilst your clay may have strong pH buffering capacity, doing so will be tricky. If you want to use levulinic and anisic acid, you shouldn't add them in their water soluble salt form (i.e. Dermosoft 1388) but as free acids. Still, you'd need a low pH.
    Heat treating your clay might also help.
    The bacteriocins in leucidal (I don't know which one but that doesn't really matter) are likely to adhere to clay and the aspen bark extract is something which troubles me somewhat: Aspen contain an elevated level of salicylates but mostly as glucosides, not free and active salicylic acid. Unless Activemicrotechnologies hydrolyses that, their extract won't be as good as pure salicylic acid. And BTW that one also requires a low pH in order to work properly.
    Which organisms did grow in the challenge test?
  • ShellyJShellyJ Member
    edited January 6
    @pharma thank you so much. 
    I adjusted the PH to 5.2. 
    So what is your suggestion? Using anicic and levulinic acid instead of dermosoft+ salicilic acid ? 

  • @pharma honestly I was about to send samples for challenge test, and I saw mold on top of the formulation. 
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