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Hi all,
To study the distribution of a drug in various compartments, do we need
to determine the concentration of drug in various compartments after a
single dose or after attaining constant blood levels obtained by
multiple dosing? Which one is more rational?
Regards,
Jimmy
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The following message was posted to: PharmPK
There is no general answer to your question I suppose. The kinetics of
concentrations in the different organs may be totally different than in
blood.
Therefore, if you determine the distribution for only one timepoint,
the only
interpretable result can be achieved at steady state, because in all
other cases
you never know in which phase of kinetics you are in a particular organ.
However, also the steady state experiment has the pitfall that in many
cases
organs which are loaded slowly, e.g. brain and adipose tissue, reach
the steady
state significantly later than blood.
A good way out of this dilemma is supporting the experiment with
PBPK-modeling.
Such simulations give an idea of the typical timescale in the various
organs.
Of course if you are only interested in the situation a certain
timepoint, e.g.
because exactly this timepoint is important for your application, than
you have
to consider only this timepoint and the decision between one
application or
steady state has to be made according to the particular application as
well.
Regards
Walter Schmitt
Bayer Technology Services
AS-Biophysics
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