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
_______________________________________________________
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
_______________________________________________________