Tuesday, November 2, 2010

Preservative: Cosmocil CQ

Cosmocil CQ is a really novel preservative, relying upon polyhexamethylene biguanide (PHMB) as the preservative, which is neither a formaldehyde releaser nor a paraben based product. The INCI is polyaminopropyl biguanide. It's both a bacteriostatic and bactericidal preservative that should be combined with a fungicide like one of the parabens, potassium sorbate, or sodium benzoate (one of the organic acids).

In my research, I have found so many conflicting bits of information about this preservative, even from the company (Arch Chemicals) in their data sheets, so I've done my best to distill it all down to something easier to understand!   

It's cationic and the manufacturer notes it is incompatible with what they call strongly anionic systems, so I'd be careful using it with shampoo, body wash, and other foamy surfactant mixes. It is effective for pH 4 to 10, so you can use it with pretty much any product we make, with the ideal being below 6. It's soluble in water, ethanol, glycerin, and propylene glycol but insoluble in vegetable and mineral oils and esters, so you'll want to use in products that contain water. You can use it in your creations in the water phase while you heat it or add it just before emulsification. (One data sheet says it's heat stable to 140˚C, but when do we ever reach those temperatures? So I'm going with the stable to 80˚C suggestion.) The most frequent suggestion is that we should add it to the water phase before heating.

Summary of Cosmocil CQ
INCI: Polyaminopropyl biguanide
Usage: From 0.05% to 1.5%. Approved at up to 1.5% in the EU and 0.5% in Japan.
Not suitable for anhydrous products. Add in the heated water phase of your products pre- or post-emulsification.
Suitable for products with pH 4 to 10.


Christine E. said...

I tried Cosmocil at .7%, with .14% potassium sorbate and .115% citric acid, as per one suggested use in this pdf, but my formulation didn't hold up for even a couple of weeks. I didn't realise it had to be used in the heated phase though, so maybe that was a factor. I tried it again at 1% with .2% potassium sorbate in a deodorant, and so far (a few weeks in), it's holding up much better.

I'm not sure this is a preservative I'd feel comfortable using at the lower end again.

I notice here, it says Cosmocil's activity against various bacteria was tested at 1.5%. I'm wondering if that is a better % to use.

I'd love to hear from anyone with more experience using it.

daniel said...

I've used since May w/ max plus k sorbate max. In addition 1% lavender essential oil, 4% ethanol. Dunno if it would be as good w/o the extras though, but so far, clean as a whistle in my normal usage- jar w/ fingers daily in it. I have 3 very close friends using lotion with same formulation in pump bottle last 9 wks also. Good feedback so far. No fur, smell, or any other funkiness. OH!! it was 65% oil phase too! So can't say w/ more water phase. Gonna formulate with 75% water phase. Gonna push it to it's max with etracts, aloe, and hydrosols!!!!!!!!!! Will see next few weeks if it can tolerate all the fresh bug food!

Christine E. said...

Thanks, Daniel,that's interesting to know.

daniel said...

Also, cut out the citric acid because cosmocil works from 4- 10 ph. Add below 100 F, way after emulsion has formed. That table in the .pdf is for wet wipes.

It took about 4 fails for me at at first to get it. Archer, the manufacturer, has terrible customer service in the tech. department.

Did you try it again in an emulsion? Best of luck to you.

Anonymous said...

Thanks so much for creating this blog, it has been an amazing help while I try and put together a cream for my eczema!

I have had made a few good batches using mineral oil, cetearyl alcohol and cetearyl olivate/sorbitan olivate and was trying to use cosmocil 1% but it would destabolize the cream if I added it after emulsification as well as in the water phase with glycerin at 3%.

A normally thick cream has turned into a watery lotion if I add it to the heated water phase. If I add it to a cooled down cream it seems to make it curdle and the water separates out.

I have seen some companies on the internet selling creams with both these ingredients and was wondering what I could be doing wrong?

Thanks for your help!

Susan Barclay-Nichols said...

Hi Kevin. Olivem 1000 is notoriously unstable. I'll be writing some posts about it a few weeks from now, so I hope you can wait for them! I suggest visiting Lotioncrafter and look for this ingredient and the data sheet. You need to stabilize it and use a stick blender and...and...and.... There are so many different things you have to take into consideration with this emulsifier. It really is a pain in the bum!

Joyce Pires said...

Hi Susan!

I created a gel with 0,1% of Cosmocil 20% and it was kept in a climatic chamber a 40°C and 75% of relative humidity to conduce an accelerated stability study. After 3 months, the amount of PHMB is 0,05%, it means that the amount declined 50% percent. The water wasn't heated during the prepare. Do you think it could be the reason of this decrease?

Beth said...

I am looking to make a goat milk lotion and keeping it as "clean" as possible. What do you recommend that I use as a preservative?

Michelle Harmond said...

Beth- don't be that person that asks a vague question when all the answers are available by clicking the keys on your keyboard.