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Re: OMEGA BLOCK with mixture model?

From: Nick Holford <n.holford>
Date: Fri, 17 Apr 2009 09:08:29 +0200

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.holford
mobile: +33 64 271-6369 (Apr 6-Jul 17 2009)
http://www.fmhs.auckland.ac.nz/sms/pharmacology/holford

Received on Fri Apr 17 2009 - 03:08:29 EDT

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