From: Martin P jedimart2004@yahoo.com
Subject: [NMusers] "First-pass" 3-compartment model
Date: Tue, August 10, 2004 8:41 am
NM users,
Is there a control routine & model out there for a "first-pass"
three-compartment open model (ie. elimination from the second
peripheral compartment rather than the central)? If not, I have a
specific formula for it that I'd like NONMEM to try and form estimates
with, but am unsure of how to write the proper routine.
Any help is greatly appreciated.
Martin
"First-pass" 3-compartment model
From: Luann Phillips luann.phillips@cognigencorp.com
Subject: RE:[NMusers] "First-pass" 3-compartment model
Date: Wed, August 11, 2004 6:47 pm
Martin,
There is not a standard ADVAN for this type model. If the system is
linear, you could implement it with ADVAN5. If you have any nonlinearity
then you would need to use ADVAN6.
Example:
Oral Drug(dose to depot) with first order absorption to the central
compartment and elimination from the peripheral cmt.
$PROB 3 cmt model with elim from peri
$INPUT <>
$DATA <>
$SUBROUTINES ADVAN5
$MODEL COMP=(DEPOT,INITIALOFF,DEFDOSE) ;cmt=1
COMP=(CENTRAL) ;cmt=2
COMP=(PERI) ;cmt=3
$PK
KA=THETA(1)*EXP(ETA(1))
CL=THETA(2)*EXP(ETA(2))
Q=THETA(3)*EXP(ETA(3))
VC=THETA(4)*EXP(ETA(4))
VP=THETA(5)*EXP(ETA(5))
S2=v2/1000;
;ADVAN5 expects Kij parameters where i=cmt number where flow originates
; j=cmt number where flow stops and 0=outside the system
; Note the following equations are just to demonstrate that you can
; still model macro parameters in ADVAN5 as long as you provide the
; equations for the micro rate constants.
; For ease of demonstration, the equations below are similar to those
; for a standard 2 cmt model with elimination from the central.
; I have not checked whether they are appropriate for a 2 cmt model with
; elimination from the peripheral.
K12=KA ;flow from depot to central
K23=Q/VC ;flow from central to peri
K32=Q/VP ;flow from peri to central
K30=CL/VP ;elimination from peri
$ERROR
same as usual
Regards,
Luann
_______________________________________________________