From: Suzette Blanchard <suzette@sdac.harvard.edu>
Subject:[NMusers] initial condition model
Date: 7/24/2003 8:25 PM
Greetings,
Could someone help me with how to set
up an initial condition - one compartment
model with first order absorption (i.e. a recursive
one compartment model with first order absorption
that would allow a random effect on the initial
concentration) in NONMEM?
Thank you,
Suzette
=================================
Suzette Blanchard, Ph.D.
Research Scientist
Frontier Science Foundation
1244 Boylston St. Suite 303
Chestnut Hill, MA 02467
Email: suzette@sdac.harvard.edu
Phone: (617) 632-2007
Fax: (617) 632-2001
initial condition model
From: Lewis B Sheiner <lewis@c255.ucsf.edu>
Subject: Re: [NMusers] initial condition model
Date: 7/25/2003 2:14 PM
Suzette,
You seem to want an intial condition on the state vector, in
which case the usual trick is to put a unit 'dose' into the
central compartment at time zero, associated with a value of
F for that compartment (and for time 0 only) which equals a
(new) theta plus a (new) eta
(see http://www.cognigencorp.com/nonmem/nm/99oct052000.html
for an extended discussion).
However, in the spirit of the approach & discussion at
http://www.cognigencorp.com/nonmem/nm/99apr022003.html,
you might instead set F for the 'initializing' dose equal
to the observed (individual-specific) baseline concentration
value times V, plus a (new) eta whose variance is constrained
to equal that of the observation error.
LBS.
--
_/ _/ _/_/ _/_/_/ _/_/_/ Lewis B Sheiner,MD (lbs@c255.ucsf.edu)
_/ _/ _/ _/ _/ Professor: Lab. Med., Biophmct. Sci.
_/ _/ _/ _/_/_/ _/_/ Mail: Box 0626, UCSF, SF,CA,94143
_/ _/ _/ _/ _/ Courier: Rm C255,521 Parnassus,SF,CA,94122
_/_/ _/_/ _/_/_/ _/ 415-476-1965 (v), 415-476-2796 (fax)
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