How to prevent soaping effect in cream

seryou

Hi everyone,

I'm formulating a magnesium cream and am having issues with it soaping when applied. The formula is as follows:

Phase A
Water 42.5%
Glycerine 5%
Magnesium chloride hexahydrate 30%

Phase B
Caprylic/capric triglycerides 3%
Avocado oil 5%
Glyceryl stearate SE 5%
Cetearyl alcohol 4%
Polysorbate 20 2%
Beeswax 1%
Shea Butter 1%
Tocopherol 0.5%

and preservative 1%

I've read that the soaping could be caused by too much fatty alcohols or too much emulsifiers, but am not sure which one it could be or what levels to drop them down to so would love to hear your thoughts. I'd like to avoid dimethicone if possible.

Thanks!

MarkBroussard

@seryou:

Try dropping your Glyceryl Stearate SE to 2% and Cetearyl Alcohol to 2%.  Why so much Polysorbate 20?

Dimethicone ... will solve your problem.  I would suggest using it.

seryou

MarkBroussard said:

@seryou:

Try dropping your Glyceryl Stearate SE to 2% and Cetearyl Alcohol to 2%.  Why so much Polysorbate 20?

Dimethicone ... will solve your problem.  I would suggest using it.

Thanks Mark, I'll try this out. What levels of Polysorbate 20 would you suggest? I'm relatively new to formulation so this formula was given to me as a starting point. I personally have no issue with dimethicone but I don't have the final say on it

MarkBroussard

@seryou:

This is not a good formula for a beginner to use as a starting point.  Making these Mg creams is highly process dependent.

Polysorbate ... try 1%.  Dimethicone ... try to convince whomever you need to that resolving soaping in this formula without Dimethicone will be quite difficult.  I fail to understand why some are opposed to using Dimethicone ... it's actually a good ingredient.

Paprik

Amen to @MarkBroussard. 

Look at your oil/butter portion - 9%. 
Look at your emulsifier portion - 12%. No wonders you have soapiness. 
It is probably grabbing oils from the skin and try to emulsify it. (that is how crème cleansers work) as you have access of it. 

You would have to significantly increase your lipid portion. 

Beeswax (as low HLB) could help with the soaping effect, but I would choose a different ingredient. Such as glyceryl stearate (glyceryl monostearate). Or Sorbitan stearate. 

However, ultimately Dimethicone would be the hero ingredient. Seriously, nothing wrong with it. 

MattTheChemist

@MarkBroussard I think I have asked this before, but I can't find the thread. Have you tried any of the dimethicone alternatives like the LexFeel N series? Do you find they also have some anti-soaping properties? Just trying to source materials for clients that are anti-silicone for whatever bizarre reason they have. 

MarkBroussard

@MattTheChemist

Yes, I have tried dimethicone alternatives.  Nothing works nearly as good as Dimethicone.  I do find that the inclusion of 1% Jojoba Esters (the KW-20 water-soluble version) is the most effective, but not as good as dimethicone.  Carbomer can also be helpful.

What I usually do with dimethicone-resistant ciients is prepare a sample with alternatives and a sample with dimethicone and send them both to compare side by side.  Most often, when they see the difference, they come to the conclusion that dimethicone is not such a bad ingredient after all.

seryou

@MarkBroussard

Would you suggest the Polysorbate 1% alongside the lowered Cetearyl Alcohol and Glyceryl Stearate levels? And if I do use dimethicone what level should i start at?

Paprik

In my opinion you can even remove the Polysorbate. 
With Dimethicone, start with 1-2%.

seryou

@Paprik I actually did try removing the Polysorbate and just using the 5% GMS SE but the phases separated as soon as I started adding the oil phase, not sure why that is

Paprik

@seryou would you have any other non-ionic emulsifier? Blend preferably? GMS SE is anionic and for denser packing it would be better to add some of non-ionic surfactant. 

Are you using high shear? 

seryou

@Paprik I'll have to check when I'm at work but we have quite a few emulsifiers/blends, off the top of my head I know we have some Emulgades and Eumulgin, as well as some GMS/PEG blends. Do you have any particular blends you recommend? Would this be in place of the Polysorbate?

I believe it was low shear, as I was using a three-blade propeller with an overhead stirrer. I read somewhere that low HLB emulsifiers can only stabilise w/o emulsions so I thought that was what was going on but I could be wrong.

MarkBroussard

@seryou

Curious ... has the formula you are working on ever been made before?  Or, are you working off of a theoretical paper formula for a new product development?

seryou

@MarkBroussard I'm not sure if this exact formula has been made, but the person who put it together for me based it off of a previous Mg cream they had made in the past (though it was written from memory so likely wouldn't be the exact same). Should GMS on its own have been enough to emulsify?

MarkBroussard

@seryou

GMS solo? ... probably not.  You should pair this up with another high HLB emulsifier that builds viscosity.

Again, if you are new to formulating, this is not a good formula for you to learn from.  Try making the cream first without the MgCl ... you'll have better success with that.  Then move on to a version with MgCl.