Wednesday, April 19, 2017

Pretty sure that's not non-toxic?

Wired magazine had a fun article about rat contraception in New York City (of course.) It had this interesting little paragraph (emphasis mine): 
Credit: Sigma-Aldrich
...ContraPest works by attacking oocytes, the egg precursors that every female mammal is born with. The active ingredient in the product is something called 4-vinylcyclohexene diepoxide, or VCD. It’s tongue-numbingly spicy, but totally non-toxic—except to oocytes. Specifically, it binds to a receptor that, when activated by a survival factor, keeps the egg precursor alive and healthy during a female’s baby-making years. But when VCD binds, it interferes with that signal and the oocyte dies. “The chemical destroys the eggs in their very smallest form so the animals can’t ovulate anymore,” says endocrinologist Pat Hoyer, who spent two decades figuring out the mechanism in mice and rats. No eggs, no offspring.
I'm not crazy in thinking something with two epoxides should have a hard time being called "totally non-toxic", am I? The Sigma-Aldrich MSDS seems to indicate that you should avoid using VCD as hand lotion...

9 comments:

  1. I just assumed it would be prone to nucleophilic attack and mess with DNA, but my brief Google detective work suggests "VCD acutely reduced hepatic levels of the antioxidant, glutathione". At any rate, I think the Wired writer might be exaggerating its safety profile.

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  2. From the SenesTech web site FAQs:

    Is there a risk to human handlers that are putting the bait out? Or to humans in general?
    No. Our product, as formulated and when used as directed, is not harmful to the skin and cannot be inhaled. Although one of our plant-derived active ingredients may have a temporary effect on fertility in humans, a 165 lb. person would have to ingest 2 gallons of the product every day for 15 days to be possibly affected. There are no documented cases of cancer or illness in humans from the two active ingredients in SenesTech’s product. In fact, our plant-derived active ingredient is being used in clinical trials to combat certain types of cancer.

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    1. Just because it doesn't have any documented cases of cancer associated with it doesn't mean it's not carcinogenic. VCD is a GHS Category 2 carcinogen (a suspected human carcinogen). Looking at the structure, I expect it would crosslink DNA quite nicely.

      Also, vinylcyclohexene is derived from butadiene, not plants. (And plant-derived doesn't imply anything about safety in the first place.)

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  3. This document (https://ehs.ucsf.edu/.../4-Vinylcyclohexene%20diepoxide%20CASNo106-87-6.doc_ says that vinylcyclohexene is a confirmed animal carcinogen, but I don't knbow what the reference is. If that's accurate, then it seems like one might be concerned, even if the carcinogenicity were in rats.

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  4. Anybody know what, if any, regulatory approval is required before this stuff can be used for the intended application? Judging from the NIOSH info, I kinda doubt it will pass (https://www.cdc.gov/niosh/ipcsneng/neng0820.html).

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    1. I would expect the EPA to say it's theirs to regulate, via the Federal Insecticides, Fungicides and Rodenticides Act (usually called FIFRA, for obvious reasons).

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  5. Remember, epoxides are not as reactive as people think. Yes, they can open but need significant encouragement.

    This is similar to when people vilify sucralose (Splenda) for having a primary chloride. Also, not very reactive.

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    1. epichlorohydrine and ethylene oxide are demonstrably very nasty to human health. Also, a Fumagillin-derived diepoxide named Beloranib originally developed for cancer/anti-angiogenesis was recently pulled from phase III clinical trials for weight loss, after two patients had died. These were morbidly obese patients with underlying genetic disorder so it is not clear if the deaths were related to treatment, however the development was halted as FDA afterwards required a whole slew of additional human safety question to be answered before the drug could be approved...

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  6. another compound which acts along the same lines is Tris(1-aziridinyl)phosphine oxide...not pretty and nothing I would consider "safe"

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