Lotion Failure - troubleshooting

MakingSkincareMakingSkincare Member, Professional formulator
edited February 2014 in Formulating
I just had my first lotion failure ever today.  Formula below. I usually heat and hold separate phases for 20 mins at 75c however following discussions in my discussion group (which includes cosmetic chemists) regarding using the one pot method, in the name of experimentation, I decided to try the one phase/pot method but with two brand new ingredients - Methyl Glucose Sesquistearate as the sole emulsifier, and cetyl palmitate (instead of cetyl alcohol).   

I used a stick blender as always.  It didn't seem too bad (but v strange consistency) until i added the cool down phase then it thinned drastically and a few mins later separated.

Were there too many silicones. vaseline and esters for the emulsifier to handle? perhaps it needs two phases, not one?? I was advised that  Methyl Glucose Sesquistearate can be used as sole emulsifier but perhaps it needed another emulsifier or a higher % ??   Tried to rescue it by adding 0.3% xanthan gum at the end but it didn't work. 

Photos showing each stage of the process here - http://www.flickr.com/photos/30114490@N07/sets/72157640843199765/ (You can view it in order horizontally and you will see in the bottom left hand side I've described what's happening and numbered the photos).

HEATED PHASE
Water (deionised)44.40%
glycerin 5.00%
sodium lactate 3.00%
200x concentrated aloe vera powder 0.10%
liquid hydrolysed oats 3.50%
shea butter 12.00%
vaseline/petroleum jelly 3.00%
c12-15  alkyl benzoate 4.00%
Coco-caprylate 4.00%
cetyl palmitate 4.00%
Methyl Glucose Sesquistearate 5.00%
meadowfoam oil 4.00%
vitamin e 0.50%
dimethicone 4.00%
COOL DOWN PHASE
cyclomethicone 2.00%
liquid germall plus (Propylene Glycol (and) Diazolidinyl Urea (and) Iodopropynyl Butylcarbamate) 0.50%
panthenol liquid 1.00%


Jane Barber
www.makingskincare.com
www.learncosmeticformulation.com (free online course)
Formulation discussion forum (18,000 members): www.facebook.com/groups/makingskincare/

Comments

  • Chemist77Chemist77 Member, PCF student
    Was HLB value taken into account, secondly with such a high amount of oil phase I suppose a mix of emulsifiers would be more effective.
  • MakingSkincareMakingSkincare Member, Professional formulator
    edited February 2014
    Bob Zonis has kindly figured it out - I have a lotion which can't decide whether its o/w or w/o!!

    Looking at the spec sheet that Bob sent me (http://www.finecon.sk/admin/pdf/DS_TEGO_Care_PS_e.pdf), the emulsifier Methyl Glucose Sesquistearate (which can be used as a sole emulsifier without using the HLB system), has very special mixing, processing requirements and depending on how you mix/process it it will turn into either a o/w or a w/o emulsion.   I wasn't aware of these special requirements so I ended up with a lotion which can't decide if it's w/o or o/w !

    To save it, I added (Palm Kernel) Oil Polyglycerol-4 Esters which comes in liquid form so didn't need heating and it made the full conversion to o/w and looks stable now.
    Jane Barber
    www.makingskincare.com
    www.learncosmeticformulation.com (free online course)
    Formulation discussion forum (18,000 members): www.facebook.com/groups/makingskincare/
  • Chemist77Chemist77 Member, PCF student
    wow some piece of info.
  • PerryPerry Administrator, Professional Chemist
    I think a general principle is that you make more stable emulsions if you use multiple emulsifiers.  Whether you can do it with one ingredient doesn't mean you should. 

    But thanks for the info!
  • MakingSkincareMakingSkincare Member, Professional formulator
    Yes that's very true Perry.  I normally use the HLB system but I wanted to clearly see what this emulsifier would be like in terms of skin feel etc.  In the future I will be pairing this up with another emulsifier.
    Jane Barber
    www.makingskincare.com
    www.learncosmeticformulation.com (free online course)
    Formulation discussion forum (18,000 members): www.facebook.com/groups/makingskincare/
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