Merckx index said:This is very interesting, and certainly relevant to the discussion. It is a very old paper, and you would think that if pharmacists were aware of the problem that long ago, they would have avoided cross-contamination by now. Those trays that were pictured upthread certainly look disposable to me, and would obviously solve the problem. But I'm not a pharmacist, and don't know what they use.
Anyway, let’s look at the numbers. I couldn’t access the full paper, so I don’t know how much variability there was in the amount of contamination, and how much it depends on the friability of the pills, let alone how friable probenecid pills are. Also, of course, if the pills are sealed in some manner, this would drastically reduce the amount of contamination.
The number they quote was obviously a worst case scenario, and corresponds to about 200 ug/capsule. Some of this would come off as the capsules were handled, filling them with bicarb, putting them in some kind of container, etc., but there would still likely be a substantial amount remaining. So if he Impey took several of these capsules, he might, as a worst case, ingest up to 1 mg. Again, this is assuming that the level of contamination was just as with aspirin in this report.
As I discussed earlier on this thread, at what I think are current detection levels, an athlete would have to consume about 25 ug probenecid to test positive within about twelve hours later. So the contamination theory is certainly possible. It depends, of course, on how much contamination probenecid pills could produce, and the level of the substance that Impey actually tested for.
Wrt taking bicarb during a it, why wouldn’t he just dissolve it in his water bottle? Would seem to be the simplest way to take it.
Thank you. Very informative and valuable data. I read it and conclude, it's a legitimate possibility in the right circumstances.