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I am currently investigating the pharmacokinetic parameters of a drug
in GHANA. Owing to lack of adequate facilities here, I have been
compelled to use only urine samples and hence only urine data in my
analysis. The urinary excretion rate data, when plotted semi
logarithmically, is similar to the log plot of plasma concentration -
time profile following oral administration of the drug.The implication
here is that the excretion rate data can be analysed in a similar
manner by non -compartmental analysis as the plama conc. -time
profile.My bone of contention, however, is how to analyse this data
of a plot of ln(excretion rate) versus time, by using non -
compartmental analysis for estimating parameters like ka, t1/2a, AUC,
V, CL, tmax, Cmax, etc.
I would be most grateful if any one could offer me detailed and
comprehensive assistance in solving this problem of mine. Reference of
any reliable source is also welcome. Thanks for your valuable help.
From Ango Bediako
Dept. of Pharmaceutics.
KNUST, Kumasi Ghana.
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The following message was posted to: PharmPK
Dear Dr Bediako,
If I understand your question you are looking for an easy way to
calculate these PKS parameters from urine data; I'm pleased to hear you
have a reasonable concentration-time profile already since in my
experience that can be difficult to obtain from urine collections.
If you were to use Pharsight's WinNonlin program to analyse this
data we have a very easy to use NCA (non-compartmental analysis) wizard
that provides 3 models;
Model 210 - Extravascular input i.e. oral
Model 211 - IV bolus
Model 212 - Constant infusion
The expected inputs for these models are start and endtime of
the urine collection intervals, volume and concentration of the urine
samples collected, dose is optional (although of course preferred).
WinNonlin also has an extensive library of other built-in PK, PD
and PK/PD models, statistics and IVIVC wizards; as well as allowing you
to build your own, user-defined, models to address any kind of data.
You will find many other people on this list are using this software and
sometimes people are able to share code for specific problems they have
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