Need some help from the chemists here

[pain-pateint]

Fellow O-Philes --

I need the chemists here to help me out with something. Recently, I came across this warning that drug testing labs are now able to distinguish marijuana use from Marinol use (Marinol is just THC in sesame oil. by prescription and at a great expense, BTW) -- see, http://blog.norml.org/2008/12/24/labs-testing-for-marijuana-use-by-marinol-patients/ . I have several clients that take Marinol and would like to know more about this.

Apparently, they are testing for some other cannabinoid besides THC. So, my questions are:

1. Exactly how do they do these tests and exactly what chemical or metabloite are they searching for? How long does this metabolite stay around?

2. For how long a period of time after marijuana use can this test make the distinction between Marinol and mj use? How "for sure" are the tests and how can they be challenged in court if necessary?

3. How expensive and prevalent are the tests, and can they be added to the "standard" five or ten panel tests I hear folks talk about?

4. Must samples be preserved or collected or processed any differently if this new testing is to be done?

4. Any other useful info you can offer to us Marinol patients to help out in not being victimized by these horrible, horrible tests?

Bad science! Bad, bad science! Bad science! Makes me feel sorry for the Catholic Church and angry at idiots like Galileo who came up with this whole "science" thing:cool:!

Thanks,

M

[ryan]

Wow, that is scary shit. I've never taken marinol but people I know who have always told me the high was alot different than smoking weed. I'm eagerly awaing someone who knows a little bit more about this to chime in with some good info..Great article OP.

[resorcinol]

1)There are multiple different assays used to test for drugs and their metabolites. The cheaper tests often look for drug by using antibodies that bind to the drug (the drug being an antigen).... a common one is Enzyme Linked Immunosorbant Assay (ELISA) -- the same test used to detect HIV infection. However these tests can give false positives as other substances besides the drug they're looking for could cause the chemical reaction.... so verification with GC/MS is always done when accuracy is important (Gas Chromatography / Mass Spectroscopy -- you can look them up if you're interested in how they work; they're two separate processes done in succession, GC separates the componants, MS tells you what's present). As far as what specific cannabinoids or metabolites they're now looking for, I don't know, and it really doesn't matter. The presence of ANY chemical known to occur in MJ along with THC proves MJ use and not just marinol, since marinol contains ONLY THC! It could be any of the 350 odd chemicals in the plant with a cannabinoid like structure. CBD is likely, though.

2)Same time period as a normal drug test for MJ... the other cannabinoids linger around in bodyfat for a long time too. If verified with GC/MS, you're screwed, a court will laugh at you (I know it sucks, drug testing is ridiculously unethical)

3)I honestly don't know. I do know that this new test won't be added to dipstick type assay tests. It'll likely be a GC/MS because distinguishing similar compounds like cannabinoids that differ only slightly in structure necessitate the accuracy of GC/MS. So it'll be somewhat expensive and I can't see it being used by anyone without a very specific reason.

4)No, I don't see why they'd need to be collected / preserved any differently.

5)Have somebody else take one marinol (who doesn't normally smoke pot), and have them piss in a cup a few hours later for you. Use this urine. Good luck finding somebody though. Synthetic urine won't work because it will show no THC, which is just as bad in this case. I'd say find a doc who won't use this test on you. If you have someone else do it, make sure they're clean of everything else too. This is what makes it difficult... it'll be tough to get a non drug user to get high on marinol for you so you can get urine with the right chemical profile. Maybe a really good friend would do it once a month for you (or however often your piss tested) assuming they don't get random UAs for work or something.

[robojunkie]

The short answer is that there is a way to test in order to differentiate marijuana use from Marinol/"dronabinol" or whatever they call the THC in the pill (chemically identical substance of course). What is done is that a compound called THCV-carboxylate (a similar cannibinoid to THC) is tested for via GC/MS and this compound as a normethyl derivative. This is only present in marijuana itself and is not produced via THC metabolism.

A GC/MS is a very precise test that is not easily susceptible to false positives. This is because the GC part (chromatography) separates out compounds via certain properties along a thin tube (diff comps have different retention times, ie how long it takes to pass through the "column") and this is often run against a standard of the comp looked for so that there is little question as to the RT. Then, this is the part that is "conclusive", the fraction with the "right" RT is blasted with electrons which breaks up the molecule into pieces. As every molecule (not including enantiomers, ie mirror image comps) is unique as in different comp equals different structure, any given drug or substance breaks up in predictable ways at specific bonds and in specific ratios. A mass/charge ratio detector then measures out the amounts, this is compared to the standard and boom, there's a positive test.

The ELISA (color test I believe, the "instant" type, I'd have to check to make sure I'm refering to the correct test name) is much less accurate and wouldn't likely be of "use" to the enemy here.

This test would be one of the high expense tests, but no different than any other GC/MS or GC/MS/MS test. The color tests are the cheapies. I honestly don't know how prevalent the test is, whether or not Marinol prescribing doctors are typically hard ass enough to want to bother to differentiate whether patients are adding pot to their medications, I tend to doubt this. Other than what metabolites are being sought there should be no difference in sample collection/storage/etc, only the actual comparison of test results to the standards in question.

Lastly I'm not sure of window for positive test but my hunch would be that it is present for less of a time period due to the presence of the carboxylate (lipophobic) group. However this is only one of many non-THC cannibinoids that could in theory be tested for and I imagine it most likely that different non-THC canns would used by different companies if any bother to do this on more than a specialty/special order type basis.

For some info on this particular metabolite check... http://www.jatox.com/abstracts/1999/may-june/222-elsohly.htm
for one write up I saw.

Hope this helps...