Methyl Paraben vs IPBC comparison as anti fungal in lotion

AbdullahAbdullah Member
in Advanced Questions
In a lotion at pH 5, in combination with phenoxyethanol or DMDM hydantoin, how much IPBC will have the same anti fungal effectiveness as 0.2% methyl Paraben?
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  • PhilGeisPhilGeis Member, Professional formulator
    try 100 ppm but you need to get it into the product - pretty insoluble.
     
  • AbdullahAbdullah Member
    PhilGeis said:
    try 100 ppm but you need to get it into the product - pretty insoluble.
     
    Thanks 

    Looks like IPBC is not a good option compared to Paraben.
  • MaydayMayday Member
    According to this paper, they got a solubility of 5.947 mol IPBC/kg in ethanol at 25C. Given a molar mass of 281.03 g/mol, that gives a solubility of 167.1% in ethanol.

    I don't think I'm mistaken in my interpretation, because of the following passage:

    [...]The solubility of triclosan and IPBC in different alcohols is too high to be measured by the analytical method; thus, the gravimetric method was selected for this study.[...]
    ⚠️ I have a lot of ideas, but not much experience! Please keep this in mind when reading my suggestions. ⚠️
  • MaydayMayday Member
    MakingCosmetics' sells IPBC in a propylene glycol solution.
    ⚠️ I have a lot of ideas, but not much experience! Please keep this in mind when reading my suggestions. ⚠️
  • AbdullahAbdullah Member
    Mayday said:
    According to this paper, they got a solubility of 5.947 mol IPBC/kg in ethanol at 25C. Given a molar mass of 281.03 g/mol, that gives a solubility of 167.1% in ethanol.

    I don't think I'm mistaken in my interpretation, because of the following passage:

    [...]The solubility of triclosan and IPBC in different alcohols is too high to be measured by the analytical method; thus, the gravimetric method was selected for this study.[...]
    My plan was to solubilize IPBC in phenoxyethanol and then add it to formula. There are 1%,2% and 10% IPBC in phenoxyethanol commercially available so solubility would not be a problem. What i wanted to know was that which one is better value for money ;). 0.2% methyl Paraben is better value for money than IPBC if they are similarly effective. 
  • PhilGeisPhilGeis Member, Professional formulator
    You can try it
    I agree - prefer parabens (0.2 methyl/0.1 propyl)/
  • AbdullahAbdullah Member
    PhilGeis said:
    You can try it
    I agree - prefer parabens (0.2 methyl/0.1 propyl)/
    Thanks a lot. 

    As i import these ingredients from another country, right now i can afford only one Paraben because i have to purchase it in 25kg standard size. So will purchase only methyl Paraben.
    I will use it in combination with phenoxyethanol or DMDM hydantoin. 

    So do you have any suggestions on how much
     methyl Paraben+ phenoxyethanol+ EDTA 
    Or 
    Methyl Paraben+ DMDM hydantoin+ EDTA?

    Both at pH 4.1 and 5.1.


  • PhilGeisPhilGeis Member, Professional formulator
    Like DMDM H combination - and suggest EDTA as well.
  • MaydayMayday Member
    Abdullah said:
    My plan was to solubilize IPBC in phenoxyethanol and then add it to formula. There are 1%,2% and 10% IPBC in phenoxyethanol commercially available so solubility would not be a problem. What i wanted to know was that which one is better value for money ;). 0.2% methyl Paraben is better value for money than IPBC if they are similarly effective. 

    If IPBC is less than 20x more expensive than methylparaben, then the IPBC would be more economical because it's only 100ppm vs 2000+ppm. Methylparaben by itself may need to increase the concentration (to 3000ppm?) if you can't pair it with other parabens.

    I still think I prefer methylparaben because of its lower irritation potential, more widespread use in cosmetics/food, and better biodegradation.

    Suggestion: Phenoxyethanol@0.5% + Methylparaben@0.3% + Disodium EDTA@0.2%

    "Preservatives for Cosmetics 2nd ed." says 0.1% free acid (0.2% Disodium EDTA) is optimal for preservative boosting. However, if the main mechanism is in chelating calcium from microbe cell membranes to weaken them, then your water hardness will make a big difference in effectiveness. The more calcium carbonate in your water, the more EDTA you will probably need.

    DMDM Hydantoin usage is up to 0.6% in EU.

    ⚠️ I have a lot of ideas, but not much experience! Please keep this in mind when reading my suggestions. ⚠️
  • AbdullahAbdullah Member
    Thanks 

    Yes the water we use is hard water. But isn't very small amount of EDTA enough to make hard water soft? Like 60ppm
  • MaydayMayday Member
    edited January 28
    Depends on the level I think.
    According to my municipality's water report, my tap water is 156mg/L CaCO3. Assuming 1mol EDTA can chelate 1mol Ca2+ ions (maybe wrong, too conservative?) gave me 0.07% (700ppm) Tetrasodium EDTA when I did these calculations a while back.
    Water hardness charts seem to top out at 180 mg/L but I bet there are places  with much higher levels all grouped into the "very high" category.
    There's also lead and copper that could be in the water as well from the pipes, probably at much lower levels though.
    ⚠️ I have a lot of ideas, but not much experience! Please keep this in mind when reading my suggestions. ⚠️
  • AbdullahAbdullah Member
    Mayday said:
    Depends on the level I think.
    According to my municipality's water report, my tap water is 156mg/L CaCO3. Assuming 1mol EDTA can chelate 1mol Ca2+ ions (maybe wrong, too conservative?) gave me 0.07% (700ppm) Tetrasodium EDTA when I did these calculations a while back.
    Water hardness charts seem to top out at 180 mg/L but I bet there are places  with much higher levels all grouped into the "very high" category.
    There's also lead and copper that could be in the water as well from the pipes, probably at much lower levels though.
    This is very hard water.

    According to this chart for CaCO3 you may need 2.5 time more EDTA by weight to chelate it.

  • MaydayMayday Member
    edited January 28
    Thank you for that table. It's good news, actually!
    How I read the table: 1g EDTA-39% solution chelates 156 mg CaCO3. So if we had pure EDTA, 1g EDTA chelates 400mg of CaCO3.
    (Then to see how related by moles... Assuming tetrasodium EDTA—else how are they getting it into the water? 0.2630mmol EDTA to 0.3996mmol CaCO3 means 1 molecule of tetrasodium EDTA chelates 1.519 molecules on average of CaCO3.)
    In my case, my tap water is 156 mg/L CaCO3. So need 0.39g/L to chelate, which is only 0.039% (390ppm).
    ⚠️ I have a lot of ideas, but not much experience! Please keep this in mind when reading my suggestions. ⚠️
  • AbdullahAbdullah Member
    Mayday said:
    Thank you for that table. It's good news, actually!
    How I read the table: 1g EDTA-39% solution chelates 156 mg CaCO3. So if we had pure EDTA, 1g EDTA chelates 400mg of CaCO3.
    (Then to see how related by moles... Assuming tetrasodium EDTA—else how are they getting it into the water? 0.2630mmol EDTA to 0.3996mmol CaCO3 means 1 molecule of tetrasodium EDTA chelates 1.519 molecules on average of CaCO3.)
    In my case, my tap water is 156 mg/L CaCO3. So need 0.39g/L to chelate, which is only 0.039% (390ppm).
    You can try this amount and see if it can make your water soft enough.
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