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Dear All,
I'm doing my PhD in Pharmacy
Title: Population Pharmacokinetic of drugs (Antibiotics)
Objective is to evaluate intersubject variability of drugs among
selected group of populations
My Question:
Minimum how many subjects will be required for evaluating intersubject
variability
With Regards
N.Raja
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At least, the data you got must cover the absorption and extinction
phase?
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The following message was posted to: PharmPK
I guess one of the issues you may need to consider is what parameters
affect
PK so the following paper may be useful:
Jamei M, Dickinson GL and Rostami-Hodjegan A (2009) A Framework for
Assessing Interindividual Variability in Pharmacokinetics Using Virtual
Human Populations and Integrating General Knowledge of Physical
Chemistry,
Biology, Anatomy, Physiology and Genetics: A Tale of 'Bottom-Up' vs
'Top-Down' Recognition of Covariates. Drug Metab Pharmacokinet 24:53-7.
The paper is freely available at:
http://www.jstage.jst.go.jp/article/dmpk/24/1/53/_pdf.
Regards
Masoud
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The following message was posted to: PharmPK
Some sampling may be needed before launching the full study. You would
then
use this to estimate needed sample size. The numbers will depend on
the
magnitude of the response, and the reliability you want to assign to
your
study. There are many texts and chapters on sampling-Prism puts out
a good
one and Gerrold ZAR's text on statistics provide guidance.
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If you search with Google for "population pharmacokinetics optimal
design" you will find many references to theory and application for
designing PK experiments including the estimation of between subject
variability.
There are some freely available programs for optimal design of
population PK trials e.g. WINPOPT, PFIM, POPED. If you search with
Google you can find the download web sites.
There is a large network of scientists who do this kind of work. If
you are serious about doing this kind of PK modelling you should try
to find someone to help you because it is not easy to start by yourself.
Here are some references to the theory and practice from the people
who started this area of optimal design and are very active in it today.
1. Mentre F, Dubruc C, Thenot JP. Population pharmacokinetic
analysis and optimization of the experimental design for mizolastine
solution in children. J Pharmacokinet Pharmacodyn. 2001;28(3):299-319.
2. Duffull SB, Mentre F, Aarons L. Optimal design of a population
pharmacodynamic experiment for ivabradine. Pharm Res. 2001;18(1):83-9.
3. Retout S, Mentre F, Bruno R. Fisher information matrix for non-
linear mixed-effects models: evaluation and application for optimal
design of enoxaparin population pharmacokinetics. Stat Med.
2002;21(18):2623-39.
4. Retout S, Mentre F. Optimisation of individual and population
designs using Splus. Journal of Pharmacokinetics and Pharmacodynamics.
2003;30(6):417-43.
--
Nick Holford, Professor Clinical Pharmacology
Dept Pharmacology & Clinical Pharmacology
University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New
Zealand
n.holford.-a-.auckland.ac.nz
http://www.fmhs.auckland.ac.nz/sms/pharmacology/holford
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