Purell has busted out the “Original Formula” label to distinguish the infamous hand gel from its successor. The active ingredient of the original formula is 62% Ethyl Alcohol, which primarily acts to denature/coagulate proteins. Bacteria, those evolving little buggers, can not become resistant to this mode of inactivation. Ethyl Alcohol also dissolves lipids, so it works better on enveloped virus (e.g. influenza) then nonenveloped virus (e.g. norovirus, adenovirus, rotavirus).
The new formulation, Purell VF481, is showing a 4 log reduction of norovirus and adenovirus using the fingerpad test with infected stool to artificially inoculate fingers. Concentrations of adeno-/noro- are determined using quantitative reverse-transcriptase, with the log reduction a comparison of concentrations on fingers before and after ABHS use. Since this is working so well against non-enveloped virus, I wonder how it does against spore-formers.
I have no idea what the active ingredient is for VF481. A Google Search of “Purell VF481″ only turns up about 170 listings. The method of ethyl alcohol inactivation doesn’t mesh with increased virucidal activity. I think there’s something else in there.
According to “Disinfection, Sterilization, and Preservation” by Seymour Block: for both bacteria and virus: methanol < ethanol < isopropanol < propan-1-ol. Maybe that has something to do with it…
Anyway they’re already selling it (in Europe at least)… so I imagine the ingredient is listed right on the packaging.
