Sunday, December 17, 2006

Anti-viral meme

Ok, so Log Base 2 has been in hibernation lately. So what has reactivated this blog? Anti-viral tissues, that's what! At the drugstore today, I saw a box of Kleenex Anti-Viral tissues. Yikes, I thought: Kleenex impregnated with Tamiflu! Well, to be honest I can't tell for sure ...

Here's how the manufacturers of Kleenex describe their product:
"Only KLEENEX® Anti-Viral* Tissue has a moisture-activated middle layer that is scientifically proven to kill cold and flu viruses.* When moisture from a runny nose, cough or sneeze comes in contact with KLEENEX® Anti-Viral* Tissue's special middle layer, cold and flu viruses are trapped and killed."
Their footnote clarifies:
"* In the tissue within 15 minutes. Virucidal against: Rhinoviruses Type 1A and 2 (rhinoviruses are the leading cause of the common cold); Influenza A and Influenza B (causes of the flu); Respiratory Syncytial Virus (RSV, the leading cause of lower respiratory infection in children)."
Incidentally, the image above depicts the RSV virus. (And double-incidentally, it bugs me that in that last sentence, the word "virus" is effectively repeated. Like when you say "PIN number". Or "double-incidentally".)

Anyway, I guess the chemical constituents of Kleenex Anti-Viral tissues are a trade secret, because the best description I can find on their website is that it's a "blue-dot layer with special anti-viral* formula". Of course! It's those ingenious blue dots!

I do wonder, however, if perhaps this will just breed Kleenex-Anti-Viral-resistant viruses. Similarly, I've wondered if the ubiquitous anti-bacterial agent, triclosan isn't doing something similar with bacteria. But maybe you could say the same thing about good old soap? Hmmm ... I think we need a microbiologist to comment.

I leave you with this rather entertaining commercial for Kleenex Anti-Viral from YouTube.

Update 04Jan2007: I did a little investigation, and believe I've uncovered the secret of the blue dots! It's U.S. patent number 7115273, which is for:
"A soothing anti-viral lotion composition and a lotioned tissue product having a surface with the lotion composition applied thereto, and methods for making and using the same. The lotion composition includes an anti-viral organic acid and a topical delivery system. The topical delivery system includes one or more polyesters which allow incorporation of the organic acids into the lotion formulation, controls their delivery, and maintains them in the stratum corneum. The lotion composition may optionally contain a surfactant, an irritation inhibiting agent, and other additives."
(In case you're wondering, those additives may include "oils, waxes, fatty alcohols, humectants, and the like.") And how do you squeeze all that into a tissue?
"The anti-viral lotion composition may be applied to the tissue product by any of the methods known in the art such as gravure printing, flexographic printing, spraying, WEKO, slot die coating, or electrostatic spraying."
Translation: blue dots! The patent goes into lots more technical detail. A brief sampling:
"Preferred anti-viral organic acids comprise at least one member selected from the group consisting of carboxylic acids having the structure R-COOH, wherein R is a C.sub.1 C.sub.6 alkyl; C.sub.1 C.sub.6 alkyl carboxy; C.sub.1 C.sub.6 alkyl carboxyhydroxy; C.sub.1 C.sub.6 alkyl carboxy halo; C.sub.1 C.sub.6 alkylcarboxy dihydroxy; C.sub.1 C.sub.6 alkyl dicarboxyhydroxy; C.sub.1 C.sub.6 lower alkenyl; C.sub.1 C.sub.6 alkenyl carboxy; C.sub.1 C.sub.6 alkenyl phenyl; or substituted phenyl radical."
That tissue you're holding is a miracle of modern chemistry!
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