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Benzoyl Peroxide Shampoo Issues. Help?
Hey there,
I was wondering if anyone would care to tackle an issues I’m having with a benzoyl peroxide shampoo using Carbopol Aqua SF-1.
Over the course of a few months it transforms, separating from a nice thick white shampoo into a solid curd suspended in a clear liquid. We were having this problem with a few other similarly based medicated shampoos and I solved the issue by switching surfactants. But the benzoyl peroxide in this formula is being particularly uncooperative. Having tried a myriad of different surfactants with variations of the same unusable result, I submitted problem to the chemists at Essential Ingredients. They came back to me with a ‘new’ formula involving yet another surfactant, which yielded even worse results after 3 months, an amorphous solid floating in clear liquid. Below is the formula. Any thoughts would be greatly appreciated. Thanks
The only surfactant I tried that didn’t created a blob was SLS. Instead it was simply rendered cloudy opaque over a few months.Benzoyl Peroxide Shampoo
Water 46%
Carbopol Aqua SF1 10%
Sulfochem ALS-K 31%
TEA 99 1%
Chembataine 4%
Curoxyl Benzoyl Peroxide 42 6.5%
Kathon CG-ICP 2.5% -
7 Replies
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Curoxyl 42 Benzoyl Peroxide is formulated as a suspension in a gel … it’s Carbomer-based, but Essential Ingredients will not provide specific information … trade secret. And it is easily dispersible in water.
Part of your problem may be that Sulfochem ALS-K is designed for low pH formulations and Carbopol Aqua is most stable at pH 6.5+.I’ve used Curoxyl 42 in a face wash and a serum with no separation problems.You might try switching to a Betaine/Sulfoacetate/Sulfosuccinate blend and eliminate the Carbopol Aqua SF-1 and try thickening with Hydroxyethylcellulose or HEC with a touch of Xanthan Gum. -
Thanks very much for the response Mark.
I like your idea of moving away from SF1, since after trying so many surfactants it seems to be the common denominator. I’ve used Natrosol HRR in our ointments but never in a shampoo as a thickener, sounds interesting. I’ll see what I can come up with.
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How about HPMC for an all COLD process, thickens better and provides a good freeze/thaw stability.
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That’s a good suggestion @Miliachemist.
@matthewk: I find that HEC gives the best results if used in the ratio 2 Parts HEC to 1 Part Xanthan Gum. I would be hesitant to use HEC alone. -
Call Essential and speak with Mike Davies. He can help.
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I’m working with their chemist at the moment. In September they sent me a new formulation still SF1 based with a new surfactant blend which yielded similar results after a month in the oven. The problem is that each iteration requires time to measure the reaction and as I said before I’ve tried nearly every surfactant available to me with similar results. One chemist I spoke with over a year ago mentioned the issue could be simply the oxidation of the BPO42 destabilizing the formula, due to it’s instability. I was told that the suspension they use is for regulating transport, but also to mitigate the inherent oxidation. I also read that certain Benzoyl Peroxide products have a shelf life of three months once opened. I’m wondering if these surfactants are accelerating the oxidation process and if this instability could be a factor in our results.
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Well … it’s a peroxide, so anything that can oxidise, will!
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