How preservatives kill microbes in cosmetics

How do microbes die from preservatives in cosmetics?

- by contacting with preservative
- by eating the preservative

Comments

  • vitalysvitalys Member
    The most preservatives destroy the cell membrane of the bacterial or fungal cells. However, some of the solutions like hypertonic solutions (NaCl for example) cause the cell death too. 
  • PhilGeisPhilGeis Member, Professional formulator
    Not much information on specifics -  that they work is enough for their suppliers and customers. Likely they have multiple killing functions, one as vitalys said re membranes.  
  • AbdullahAbdullah Member
    @vitalys @PhilGeis ;
    So at molecular level if a molecule of a preservative worked on and destroyed the cell membrane of a microb and killed it, would that molecule still be available there to do that with other microbes or it will not function the same anymore? 
  • vitalysvitalys Member
    @Abdullah
    All the preservatives work on the molecular level. Some of them come into direct chemical contact with membrane lipids (for instance alkali) and saponify them whilst another denature the proteins (formaldehyde and formaldehyde releasers), third disrupt enzymatic system of the bacteria or fungi, fourth changes the intracellular pH of the cell, which lead to the cell death. 
  • AbdullahAbdullah Member
    @vitalys thanks
  • AbdullahAbdullah Member
    @vitalys thanks

    My point is this. For example
    Piroctone Olamine is used @ %0.05-0.2 in leave on anti dandruff Products according to Clariant. There is also a broad spectrum preservative blend nipaquard po5 by Clariant (phenoxyethanol %0.95, Piroctone Olamine %0.05). If we use this preservative blend to protect a leave on Product itself, and even add an extra %0.05 or 0.1 Piroctone Olamine, would this Piroctone Olamine be available to kill dandruff causing yeasts on scalp of consumer after dealing and killing microbes in the Product it self?

     Or should i use another broad spectrum preservative blend to kill microbes inside the product itself and let Piroctone Olamine be available to kill yeasts on consumer scalp?


  • PhilGeisPhilGeis Member, Professional formulator
    You need a preservative system in addition to your active - Piroctone olamine. Assume you're developing an antidandruff shampoo. This would be a drug product in some countries - have you addressed drug product regulations in your country?
  • AbdullahAbdullah Member
    edited May 10
    @PhilGeis currently i am using it only in Shampoo for preservation purpose at %0.04 with %0.8 phenoxyethanol. I use this because it is less expensive and more strong than what i previously used( %0.1 caprylhydroxamic acid+ %1 Glyceryl Caprylate). I don't claim or expect it to help dandruff. I don't even think that at such small quantity in a rinse off product it would help with dandruff. But i have plan for a leave on Product with small quantity of this ingredient after making completely sure that it can really help with dandruff in ≤%0.1 .

    If i claim "helps with dandruff", does it make a cosmetic Product a drug? 
  • PhilGeisPhilGeis Member, Professional formulator
    Have you PET generated data for its preservation effect?.  There are many materials on positive lists that are pretty useless as preservative.   It's pretty insoluble in water - tho it reportedly can be dispersed surfactant solutions.
    Caprylhydroxamic acid and glyceryl caprylate are pretty poor preservatives for comparison.

    Anti-dandruff is a drug claim in US and Piroctone olamine is not an approved active.  Don't think it is in EU.
  • AbdullahAbdullah Member
    edited May 10
    @PhilGeis ;
    Have you PET generated data for its preservation effect? no. Isn't available in our country or at least i don't know where to do it.
    Currently In order to be sure about effectiveness of my preservative system i copy popular broad spectrum blends after I find examples of this blend used in the same product that i want to use it and shows its efficacy (in this case shampoo) and then use it at maximum allowance level.

    Caprylhydroxamic acid+ Glyceryl Caprylate was a copy from Inolex but when you said it is not strong enough specially in Shampoo i changed it to this one.

    It is very easily soluble in surfactant. I mix it with CAPB and then add it to water. Cold process and very easily soluble.

    This is the nipaquard po5 composition. 
    Phenoxyethanol  %0.95
    Piroctone Olamine  %0.05

    And according to Clariant examples in Shampoo It kills all bacteria is 2 days and fungi in 14 days. This is at %0.5 of this preservative is shampoo formula that even doesn't have chelating agent. 

    I don't know where did i read that "it helps cure something" does mean "it cures something" so it is not a drug claim. 
    Maybe i have misunderstood. 
  • PhilGeisPhilGeis Member, Professional formulator
    edited May 10
    "Broad spectrum" is marketing hype - do not rely on supplier data and claims.  Octopirox (Piroctone olamine) is primarily a substantive antifungal in context of dandruff treatment.    

    If you can't access PET (and that is a problem as you are responsible for the microbiological safety of your products), use systems found in major marketer products of the same type.  You'll not find much/any Octopirox there.
  • AbdullahAbdullah Member
    @PhilGeis i will take this in mind.
    Thanks
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