Drug info - Alkaloid decomposition in dry leaves

[amor999]

Cocaine in dry coca leaves (or tea) decomposes in time, even if the coca tea is stored in the best possible way (in closed boxes, at room temperature or lower).

Question: which is the decomposition rate?

Some info from the web:

From the old book "Indigenous Drugs of India" by Chopra, (even if coca leaves are not a Drug of India) coca leaves are mentioned and cocaine is supposed to be practically lost after seven months. But this time seems too short to me.

Other sources says several months or 1 year.

An interesting article (Manufacture of cocaine) says that the cocaine content (in coca leaves from Yungas, Cuzco and Mapiri) is
initially 0.7%, then drops to 0.5% after 1 month;
then becomes 0.4% after 6 mo; 0.3% after 1 year;
0.15% after 2 years; and 0% after 3 years (no trace)

However, an academic article by Aynilian, Farnworth et al says that cocaine is found in old herbarium specimens. A 44-year old coca leaf still contained 0,03%, that is quite much, considering that the leaves at the beginning have
a content of 0,7% (of the dry weight).
Is it possible that herbarium specimens are preserved in a special way? (However, someone says just the contrary, that the preservation treatment immediately destroys the alkaloids).

Suppose that the coca tea is actually coca flour/powder (grinded coca leaves): is this situation supposed to make cocaine decomposition faster?
And what if the coca flour is pressed in a closed box?
Is this supposed to make decomposition slower?

Final question: after 2 years, is it likely that coca flour in such situation still contains 0.1% cocaine or so?

Thanks
Amor999

Reputation Comments on this post:

very good questions, thought-provoking