Lotion Formulation...What am I doing wrong??

Chloe_LJChloe_LJ Member, PCF student
Hey there. I'm trying to formulate a lotion based off of an existing product. The product is great, it's thick and smooth and absorbs very nicely. I've attempted to replicate it with various ratios of the ingredients listed, but cannot get my version to stay emulsified. The ingredients listed that I would imagine act as the emulsifiers are stearic acid, beeswax, and cetyl alcohol, and I know none of these things are typically utilized as emulsifiers themselves. I heat both the water and oil phases to 70-80 degrees C and mix with an emulsion blender. What am I doing wrong that's causing my lotion to separate? Are there factors I'm not considering? Thanks in advance for any insight.

Comments

  • You need to saponify stearic acid so it can act as proper emulsifier. You'll need an alkali like triethanolamine or sodium hydroxide.
  • Chloe_LJChloe_LJ Member, PCF student
    You need to saponify stearic acid so it can act as proper emulsifier. You'll need an alkali like triethanolamine or sodium hydroxide.
    Would benzyl alcohol cause saponification in stearic acid? If not, then there's nothing on the ingredient list of the existing product to cause that reaction...
  • Chloe_LJ said:
    You need to saponify stearic acid so it can act as proper emulsifier. You'll need an alkali like triethanolamine or sodium hydroxide.
    Would benzyl alcohol cause saponification in stearic acid? If not, then there's nothing on the ingredient list of the existing product to cause that reaction...
    It wouldn’t. Can you share LOI?
  • PharmaPharma Member, Pharmacist
    It doesn't necessarily need saponification: Search the forum for 'cold cream'.
  • Pharma said:
    It doesn't necessarily need saponification: Search the forum for 'cold cream'.
    To my understanding cold creams are produced by saponifying fatty acids present in beeswax (e.g. cerotic acid) with borax. Is there a way to produce stable cold creams without any base?
  • MarkBroussardMarkBroussard Member, Professional Chemist
    Potassium Hydroxide will yield a softer, more shiny white cold cream that Borax or Sodium Hydroxide.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • PharmaPharma Member, Pharmacist
    Original cold cream relied on wax only which hardened the 'emulsion'... however, this approach has been abondoned by most due to its inherent instability issue.
    In Europe, small additions of sodium or potassium soaps or standard emulsifiers are used to increase stability instead of borax which is more common in northern America.
    An example formulation made and used in hospitals in Lucerne: Wax 7g, cetyl palmitate 8g, almond oil 60g, water 26g
  • GordofGordof Member
    Depending on the amount of oil in the oil phase you can stabilize only with beeswax and Cetearyl Alcohol and stearic acid. But the Productions steps are very important. 

    You need to heat oil and Water to 75 - 80 °C. Add the Cetearylalcohol to the Water Phase and let it melt. Homogenize for 2 to 3 minutes without oil just with the Cetearyl alcohol. Afterwards, do the Emulsification step adding oil to water Slowly. under homogenisation and then homogenize (dose not look stable at that point). 

    cool down to 40 °C under slight homogenisation and steering and Homogenaze another 3 to 5 min due to the fact that Cetearyl alcohol will recrystallize as well as the Waxes and they need to be very fine dispersed in the system. 

    Cool down under stirring until the product is at 25-20 °C (maybe you need to homogenize a little to get an even creme depending on the waxes and the melting points.

    I developed 2 Products that way but it would be easier as the others wrote if you just use some alkali for the stearic acid that would boost the stability of the system quite a lot. 

    Tobias 
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