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Re: Population PKPD using hair drug concentration

From: Leonid Gibiansky <lgibiansky>
Date: Fri, 12 Jun 2015 09:54:45 -0400

Dear Bernard,

This looks like really interesting problem. Based on the idea that it
should be a long delay, I would start with the transit compartment model
(you can google for the references on this type of models) with the
input from the plasma compartment. The last compartment will represent a
barber shop. The number of transit compartment can be increased until
you get a sufficiently long delay. Observation compartment can be either
the last one, or the sum of several, depending on how measurements are
done (at a particular hair length, or by grinding the hair together
before measurement). Depending on whether hair can eliminate the drug
(or it happens only in the barber shop), hair clearance can be assigned
to all or only to the last of those transit compartments.

It could be that a simple effect compartment model with a very slow ke0
could describe it as well but you should be able to see it by increasing
or decreasing the number of transit compartments.


Leonid Gibiansky, Ph.D.
President, QuantPharm LLC
e-mail: LGibiansky at
tel: (301) 767 5566

On 6/12/2015 8:56 AM, Bernard Ngara wrote:
> Dear all
> I am a working on a study that measures both short and long term
> exposure to drug using plasma and hair drug concentration. What
> methods can I use to model hair drug concentration. You can give
> references so that I can read.
> Thanks once again.
> Regards
Received on Fri Jun 12 2015 - 09:54:45 EDT

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