Which of these two preservatives is stronger?

Which preservative is stronger? 

1. 90% phenoxyethanol+ 10% caprylyl Glycol
2. 90% phenoxyethanol+10% Ethylhexylglycerin


  • PharmaPharma Member, Pharmacist
    As usual, the correct answer is 'It depends' ;) .
  • PhilGeisPhilGeis Member, Professional formulator
    edited August 9
    As Pharma said - and neither is esp good vs fungi. nor shlould be considered a complete preservative system.
  • AbdullahAbdullah Member
    edited August 9
    @Pharma @PhilGeis yeah everything depends on whole formula and also this preservative is not very strong for fungi. But if we use this at 1% in shampoo which one of these two will be stronger? 
    Shampoo is SLS/SLES/CAPB/APG at 3/7/2/2 active surfactant
  • MicroformulationMicroformulation Member, Professional Chemist
    What is your metric for "stronger?" Perhaps you could better say "more effective." In that case, like in every preservation system, this could be objectively graded solely by PET/Challenge Testing.
    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications. BS.Pharm Albany College of Pharmacy, Union University.
  • PaprikPaprik Member
    But if you would ask which one I like more, No. 2 is the answer :D 

    1. usage between 0.75 - 1.5%, pH range 4-8. heat stable "only" to 80°C
    2. usage between 0.5 - 1%, pH range <12, heat stable.

  • @Paprik thanks
  • @Microformulation yeah more effective i mean. 
  • PhilGeisPhilGeis Member, Professional formulator
    Answer to specific question is neither - they're both just phenoxy with a little extra boost and each could be argued a little better than the other.  To get a functional answer re. a complete system, you'd need to include product formula, package and making quality dynamics. 

    As Microformulation said, challenge test is metric.  That's all you have, but it's not validated to making or consumer use.  FDA enforcement reports - no doubt every cosmetic recalled passed a (at least USP) challenge test.  It's a price of entry but good and poor systems pass - and the very great number of  recalls in recent years is primarily associated with this prob pass and certain primary reliance on politically-correct, marginal preservatives.  I'd classify as such cap glycol, glyc caprylate and other esters, PEA, EHG, cap hydroxamate, gluconolac tone, etc.  Maybe not only due to the preservative systems - alone they're poor but the typically small to moderate sized companies recalling products likely have a poor understanding of micro risk control in formula, package and making context.

  • @PhilGeis it is 
    SLS/SLES/CAPB/APG @3/7/2/2 active surfactants.
    Cationic guar 0.2%
    Amodimethicone emulsion 2.5%(0.75% silicone)
    Guar gum 0.1%
    EO 0.5%
    Citric acid 
    pH 5.1

    The bottle is HDPE but i want to change to PET to reduce the cost.
     with flip top cap.
    Sizes 200ml and 500ml.
  • PhilGeisPhilGeis Member, Professional formulator
    edited August 11
    Neither is esp good.  Suppose your policy prevents isothiazolinone.  I'd prob use #2 and add EDTA and NaBenzoate.  Better check stability in PET.  Suggest ISO AET with added cepacia.

    What is your making risk?
  • @PhilGeis thanks 
    What do you mean by "What is your making risk"?
  • PhilGeisPhilGeis Member, Professional formulator
    What is the microbiological quality of your manufacture?
  • @PhilGeis i think it is good. 
    I make shampoo in 200kg tank each time.
    I wash the tank properly after emptying the tank and before using it again. 
    When not in use, the tank is in the same room with raw materials, completely dry. During use we shift it to another room.
    All other equipments are cleaned, used and stored like this.
    I haven't used alcohol to clean the tank or other equipments yet.

  • PhilGeisPhilGeis Member, Professional formulator
  • @PhilGeis it follows all these guidelines.

    how do you sanitize?
    i wash them properly befor and after work and store them dry and clean. What else should i do for sanitization and why?
  • PhilGeisPhilGeis Member, Professional formulator
    Sanitization to kill microorganisms, esp. those that can contaminate product.  Many use alcohol - esp. 70% ethanol.
  • @PhilGeis which equipments should i sanitize? 
    Tank, homogenizer, Pipes, other small equipment Or all equipments?

    How many times and when should i sanitize with alcohol?

  • PhilGeisPhilGeis Member, Professional formulator
    All those. - everything that touches product.
    Alcohol is best for surfaces and small objects - that should be cleaned before santizatiion and covered until used.  Tanks, lines, flow paths best with heat (hot water or steam ) and in an assembled florm through proess..  Chemical sanitization (hypochlorite) requires rinsing and that demands high standrd foir rinse water.
  • @PhilGeis how much contact time of alcohol 70% will sanitize the equipments? Seconds or minutes or more?

  • PhilGeisPhilGeis Member, Professional formulator
    tens of seconds to 1 minute on a clean surface
  • @PhilGeis how should i use alcohol? 
    I mean is it ok to put some alcohol on a garment and apply to surface of tank or any other method? 

    How should i sanitize the 2 meter pipes? 
  • PhilGeisPhilGeis Member, Professional formulator
    edited August 17
    Tyically sprayed.
    Tanks are a problem - you'll approach a flammability/exp[osion hazard in a closed vessel. Can you use hot water?
    You should sanitize all product contact surfaces,
  • @PhilGeis it will be open when vassel during spring alcohol. Do you mean if i close it after spraying i will approach flammability? 

    Yes i can use hot water. 
  • PhilGeisPhilGeis Member, Professional formulator
    Use hot water  - 80C
  • @PhilGeis for how much time? 
  • PhilGeisPhilGeis Member, Professional formulator
    edited August 18
    30 minutes - this allows enough time thag heat penetrates 
  • @PhilGeis thanks
Sign In or Register to comment.