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BP and Water



So I guess BP is water insoluble, meaning that it cannot be dissovled by water. This is actually interesting to know because (yes, I did have a mishap with my water bottle this morning) but this also great information for all of the swimmers out there.

So, (and this might be a stupid question to ask, but I must) BP cannot be "washed off" at all (well after it dries)? I know it is absorbed...but just into the skin? Into the system? I will study this a bit more, and I'm simply curious.

Here is an excerpt I found discussing the solubility of BP:

"One of the most commonly used ingredients in over-the-counter acne treatments in cream, gel, and wash form is benzoyl peroxide. It is an anti-bacterial agent that kills the bacterium (Propionibacterium acne) involved in the formation of acne. The formulation of these products is extremely difficult owing to the instability of benzoyl peroxide. Benzoyl peroxide is soluble in polyethylene glycol (PEG) and isopropyl myristate, but it is not stable in these solvents. Also, it is practically insoluble in water and only slightly soluble in ethanol but is very stable in the presence of these solvents. The stability of benzoyl peroxide in PEG or isopropyl myristate is increased upon addition of water or ethanol. Students take on the role of the process chemist and use peroxide strips to investigate the stability of benzoyl peroxide in an over-the-counter acne medication in solutions of water, ethanol, PEG, 50:50 ethanol:PEG, 50:50 water:PEG, isopropyl myristate, and 50:50 ethanol:isopropyl myristate."-The Journal of Chemical Education

So not only is it not watre soluble, but it is stable in this environment.