Probiotics and Preservatives

Hi there, 

I am currently doing a cosmetic chemistry course and have a formulation project underway. I don't have the full formulation thought out yet but I would like to use a Lactobacillus Ferment Lysate in my formula. My question is more general in terms of formulations:

Do you use a preservative like propylene glycol etc. when there are probiotics in the formula? If not, do you formulate under heavy (more than normal) sterilized conditions?

Thanks

Comments

  • PerryPerry Administrator, Professional Chemist
    What are you hoping the lactobacillus ferment lysate will do in the formula?

    Propylene glycol is not a preservative.  You need to use a proper antimicrobial preservative like parabens, formaldehyde donors, phenoxyethanol, etc.

    Lysates are by definition non-living and an antimicrobial preservative will not have any impact on them.
  • Bill_TogeBill_Toge Member, Professional Chemist
    Perry said:
    Propylene glycol is not a preservative.  You need to use a proper antimicrobial preservative like parabens, formaldehyde donors, phenoxyethanol, etc.
    it can be, at a sufficiently high level (15% or higher) - 1,2-diols have antimicrobial effects and the MIC decreases as the chain length increases
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • PerryPerry Administrator, Professional Chemist
    @Bill_Toge - good point. 

    Speaking of MIC, do you know a source listing the MIC of common ingredients?

  • PharmaPharma Member, Pharmacist
    Perry said:
    ...Speaking of MIC, do you know a source listing the MIC of common ingredients?

    I know, it's an older thread but you might still appreciate an answer.
    There is not ONE MIC for a certain compound. Every antimicrobial has a one (or several depending on how it was determined) MIC for every microbial species or even every serovar/cultivar. Unfortunately, this means that there is no reliable listing. You'll find short list for antibiotics against common pathogens, though.
  • PerryPerry Administrator, Professional Chemist
    @Pharma - Thanks. I was curious and what you say makes sense. The whole notion of an MIC applicable to all microorganisms seemed dubious.

  • PharmaPharma Member, Pharmacist
    You're welcome.
    That's the reason why preservatives have recommended usage ranges/concentrations instead. These, however, are usually well above the MIC.
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