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Peter,
>
> I would appreciate receiving any available information (especially
> references) concerning the absorption of alcohol (ethanol) in humans. What
> is an accepted Ka value for alcohol? Most papers in the forensic
> literature focus on the time of the peak BAC and then, in effect, treat
> alcohol absorption as a zero-order process (with parameters dependent upon
> the type of alcoholic beverage consumed).
You might take a look at a review on ethanol PK in Clinical
Pharmacokinetics 1987; 13:273-292 for an overview of absorption models.
A simple first-order absorption model (as implied by your request for an
'accepted Ka') is probably as inappropriate as asking for an 'accepted
half-life' for ethanol i.e. models which describe ethanol input and
elimination usually need to be more sophisticated than the elementary
first-order one compartment stuff. But it depends on your application of
the model how fancy you need to be. Ethanol has rate dependent extraction
when taken orally (probably in the liver - I dont accept the gastric ADH
hypothesis). So if you really want to model oral absorption you cant
assume the extent of absorption will be independent of absorption rate.
--
Nick Holford, Dept Pharmacology & Clinical Pharmacology
University of Auckland, Private Bag 92019, Auckland, New Zealand
email:n.holford.at.auckland.ac.nz http://www.phm.auckland.ac.nz
Tel:+64 (9) 373-7599 x 6730 Fax:373-7556
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Maybe I'm all wet, but if you're looking for a Ka for EtOH, it would
seem that you would have to separate the absorbtion component from the
elimination portion. Saturation of the elimination mechanism would be needed.
At that point, you could do a comparison between oral absorbtion and IV infusin.
(as long as you had a big enought sample population)
Bob B.
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Take for example, treatment of a methanol overdose. Ethanol treatment
can be very close to the enzyme saturation point. If at that point, you
converted from IV EtOH to PO EtOH, wouldn't that give you some decent Ka info?
Bob B.
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