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SILICONES
Hi,
I am formulating a cream and I want to use Cyclomethicone Pentamer (13%). If I am not wrong….usually silicones are add to the oil face before emulsion but I Know that Cyclomethicone Pentamer is volatile. So, to avoid its volatility, would it be correct if I added at the end of the formulation (below 30ºC) solubilized in alcohol? or it is better to added alone after adding alcohol (7%)? I am not sure about that…
I would appreciate your help. -
4 Replies
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I’m uncertain as to what you are referring, but from the context, I would hazard a guess that it’s cyclopentasiloxane? Otherwise known as fluid 1585.
13% would be a LOT. It’s often found in hair care because it volatilises under a hair dryer so it’s useful as a “disappearing vehicle”.
I really doubt you can dissolve it in alcohol. I do have experience with it in skin creams. I use it at 0.15% (and dimethicone petrolatum at 0.15%) in a cream that is basically a knock-off of an E&C hand cream. It (in my opinion) should be treated as any other kind of silicone in that it needs an emulsifier, and as we all know, silicones do not behave in a similar and predictable way such as esters or polar oils. So, the creams that have silicones in, I use stabilisers to prevent emulsion failure. -
While Cyclopentasiloxane is volatile, you do not need to cool down that low before incorporating it into the emulsion … cool your emulsion down to 45C or so and then incorporate the Cyclopentasiloxane under homogenization. You really don’t need to add more than 0.5% to 1.0% unless you have some specific reason for adding much more. No need to mix it with alcohol.
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Thank you very much… yes I know its too much % of silicone but I can’t change the estructure… only the elaboration….
Belassi can you recommend me any silicone emulsion stabilizers for other times. I would appreciate it
Thank you again!
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You can use carbomer, eg Carbopol 940, probably about 0.2% and that will need an appropriate pH range; or choose a different carbomer if you require a more extreme pH. The sensorials of different carbomers are noticeably different on the skin. Ultrez 20 is not like 940.
Or you could use a gum or mixture of gums. 0.2% Xanthan gum is an effective stabiliser with acceptable sensorials and a bit less fussy to formulate with than carbomers, and tolerates a wider pH range.
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