Preservative System

JonahRayJonahRay Member
edited April 11 in Formulating
Hi guys!

My team has been working on 3 o/w emulsions and we were using a blend of Phenoxyethanol + Caprylyl Gycol as our preservative system. We had 100 individuals try our products and roughly 30% reported a 'warming','tingling' or 'burning sensation'. We were VERY surprised by this reaction. Through a knock out experiment and further tests we discovered the preservative blend of Phenoxyethanol + Caprylyl Glycol was the problem ingredient. As we are trying to achieve a more 'clean formulation' for our client, they've restricted what we can use as preservatives. I now have a few samples that I've collected and I would like to know your opinion on them and maybe help determine which of these 'alternative' preservative systems is likely more robust..

1) Triethylcitrate + Caprylyl Glycol + Benzoic Acid
2) Caprylhydroxamic Acid + 1,2-Hexanediol + Propanediol
3) Caprylhydroxamic Acid + 1,2-Hexanediol + Butylene Glycol
4) Benzyl Alcohol + Benzoic Acid + Glycerin + Sorbic Acid

I'm aware that some have different pH restrictions. We also tried 2 additional preservatives but they had really strange smells that our focus group did not enjoy. Those were:

5) Sodium Levulinate + Potassium Sorbate
6) Gluconolactone + Sodium Benzoate

Comments

  • MarkBroussardMarkBroussard Member, Professional Chemist
    @JonahRay:

    I am particularly fond of:

    Penethyl Alcohol + Pentylene Glycol + Propanediol (Linatural Ultra-3 from Lincoln Fine Ingredients) ... very effective and it has a broad pH range.

    Dermosoft 1388 from Dr. Straetman's:  Glycerin, Water, Sodium Levulinate, Sodium Anisate.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • @MarkBroussard Thank you for suggesting additional options. Unfortunately at the moment I only have those listed above to play with. Which would you suggest?
  • PerryPerry Administrator, Professional Chemist
    I'd say try #4 and #1 on your list. But you'll have to keep your pH below 5.0
  • @Perry Thanks!

  • MarkBroussardMarkBroussard Member, Professional Chemist
    @JonahRay:

    #1 contains Caprylyl Glycol and Benzoic Acid, #4 contains Benzyl Alcohol ... so, if you are trying to stay away from a preservative that has ingredients that can cause irritation or flushing reaction, your best bet would be #2.

    I've used it before and it is an effective preservative.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • @MarkBroussard Thanks for you help! Lots to think about!
  • Bill_TogeBill_Toge Member, Professional Chemist
    edited April 11
    in addition to the above, glyceryl caprylate works well in combination with others - it's strong against bacteria but weaker against yeasts and moulds
    Cosphatec GmbH have a wide range of preservatives, with plenty of technical data behind them
    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
  • MarkBroussardMarkBroussard Member, Professional Chemist
    But, do take care with Glyceryl Caprylate ... you need to add it when your emulsion cools down to room temperature.  Even then, you should expect some loss in viscosity that could be significant and, depending on the emulsifiers, it make break the emulsion completely.  Be sure to not use more than 0.3%, so you would need to complement it with another preservative.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

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