Home Cosmetic Science Talk Formulating Preservative System

  • Preservative System

    Posted by JonahRay on April 11, 2019 at 5:08 pm

    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

    MarkBroussard replied 5 years, 3 months ago 4 Members · 8 Replies
  • 8 Replies
  • MarkBroussard

    Member
    April 11, 2019 at 5:50 pm

    @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.

  • JonahRay

    Member
    April 11, 2019 at 5:54 pm

    @MarkBroussard Thank you for suggesting additional options. Unfortunately at the moment I only have those listed above to play with. Which would you suggest?

  • OldPerry

    Member
    April 11, 2019 at 6:11 pm

    I’d say try #4 and #1 on your list. But you’ll have to keep your pH below 5.0

  • JonahRay

    Member
    April 11, 2019 at 6:17 pm

    @Perry Thanks!

  • MarkBroussard

    Member
    April 11, 2019 at 6:24 pm

    @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.

  • JonahRay

    Member
    April 11, 2019 at 6:33 pm

    @MarkBroussard Thanks for you help! Lots to think about!

  • Bill_Toge

    Member
    April 11, 2019 at 7:00 pm
    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
  • MarkBroussard

    Member
    April 11, 2019 at 8:35 pm

    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.

Log in to reply.