Andreas,
Thanks for the suggestion. However, I think its only necessary to
enforce 0 to 1 boundaries on the individual value of F1 when one is
modelling absolute bioavailability.
In this example I gave the individual 'apparent' bioavailability can be
due to a variety of differences from the implicit mean of 1 (e.g. actual
bioavailability, protein binding, dose errors, etc). The only constraint
required is that F1 be non-negative. This is taken care of by the use of
EXP transformation of ETA.
Nick
andreas lindauer wrote:
Nick,
In your code example for the estimation of a 'relative
bioavailability' wouldn't it be necessary to use a logit
transformation to keep F1 between 0 and 1? Something like: F1 =
1/(1+exp(BSV_F1))
Regards, Andreas.
____________________________
Andreas Lindauer
Department of Clinical Pharmacy
Institute of Pharmacy
University of Bonn
An der Immenburg 4
D-53121 Bonn
phone: + 49 228 73 5781
fax: + 49 228 73 9757
--
Nick Holford, Dept Pharmacology & Clinical Pharmacology
University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand
n.holf...@auckland.ac.nz tel:+64(9)923-6730 fax:+64(9)373-7090
mobile: +33 64 271-6369 (Apr 6-Jul 17 2009)
http://www.fmhs.auckland.ac.nz/sms/pharmacology/holford
