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Re: Scaling for pediatric study planning

From: Leonid Gibiansky <LGibiansky>
Date: Fri, 19 Sep 2008 11:20:49 -0400

Just to add:

c) how do we allometrically scale a VM rate constant of the
Michaelis-Menten elimination model:

DADT(1)= ... -A(1)*VM/(KM+C1)

d) do we need to allometrically scale a KM constant of the
Michaelis-Menten elimination model ?

any experience with these quantities (for example, if they were
estimated, what were the estimates, with the precision)?

My suggestion would be NOT to scale a), b) and d), and scale VM as the
rate constant (~ WT**(-0.25)) but I do not have "rock-solid" data to
support those suggestions.

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

> Dear NM_Users,
> we have all been good students and listened to Nick when he told us
> again and again the rock-solid truths of allometry:
> Volume: *(WT/70)
> CL: *(WT/70)**0.75
> any rate constant related to distribution or elimination: *(WT/70)**(-0.25)
> Here my questions:
> a) how do we allometrically scale a first-order rate constant of
> absorption after oral dosing?
> b) how do we allometrically scale a first-order rate constant of
> absorption from a subcutaneous injection site?
> Thank you for your thoughts,
> Joachim
> __________________________________________
> Joachim GREVEL, Ph.D.
> MERCK SERONO International S.A.
> Exploratory Medicine
> 1202 Geneva
> Tel: +41.22.414.4751
> Fax: +41.22.414.3059
> Email: joachim.grevel
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Received on Fri Sep 19 2008 - 11:20:49 EDT

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