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Hi
Does anybody know what to do when doing a repeated doses
pharmacokinetic experience the trough concentrations cannot be
measured or fall below the quantification limits of the assay?
Thanks for your help.
marcela
Back to the Top
Hi
Does anybody know what to do when doing a repeated doses pharmacokinetic
experience the through concentrations cannot be measured or fall bellow
the quantification limits of the assay?
Thanks for your help.
marcela
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[Let's see if this gets out ;-) -db]
Dear Marcela:
Actually, in PK work there is no lower limit of
quantification. In toxicology, where the sample is the only source of
information as to whether or not the drug is present, yes, of course.
However, in PK work, as the drug is usually excreted with some sort
of a half-time, you actually know the drug is never really ever gone.
You know when the dose way given and the sample drawn. So you know
the drug is present. The only question then is how much is present -
a very different question. We have said this for quite a while. The
issue is discussed in Therap. Drug Monit. 15: 380-393, 1993, and has
been many times in this bulletin board, so I won't inflict this on
everyone again.
Best regards,
Roger Jelliffe
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Copyright 1995-2010 David W. A. Bourne (david@boomer.org)