I have found Harris et al, 2003, (see attached) which does attempt to measure bio-availability through intranasal and "smoking" ROA.

This study claims to demonstrate that intranasl administration is more efficient than vaporistaion/inhalation ("smoking"), which does not concur with my observations of people using "Ice" in the community.

I thought the bio-availability from intranasal route sounded quite high, til I read the methods; they administered the drug in a isotonic solution delivered as a fine mist spayed onto the mucosa, so it’s not a very good model of how people insufflate ("snort") it out here in the real world and is probably an overestimate…

Harris et al estimate for vaporisation/inhalation route is that 67% of the inhaled dose (+ or – 8%) gets into the plasma.

However they also state that up to 60% of the dose might be left in the pipe or destroyed through pyrolysis, and so not inhaled.

The device used was a “temperature controlled pipe” and I wonder if an experienced methamphetamine smoker using a glass pipe and a turbo lighter might learn to vaporise the drug more efficiently than a lab device designed by non-users, and also to inhale it in the most efficient way as well?

If anyone is aware of any published literature that is more definitive or more recent than this article, please post a reply here.

Thanks,

Paul.

This study; Pharmacokinetics of methamphetamine self-administered to human subjects by smoking S-(+)-methamphetamine hydrochloride.

Drug Metab Dispos July 1993 21:717-723; published online July 1, 1993, states the bioavailability of smoked methamphetamine was 90.3 +/- 10.4%.

I'll post the full text if I can get a copy.

Here it is, (attached). This study supports the general consensus of opinion, (that ~90% or more of the dose is absorbed via vapourisation/inhalation routes of administration).

There doesn't appear to be very much published research on this topic at all- if any readers are aware of any other studies please let me know.