NONMEM Users Network Archive

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Re: Predict AUC based on trough concentrations

From: Leonid Gibiansky <LGibiansky>
Date: Thu, 18 Feb 2010 00:16:34 -0500

Yaming
I think you need to have THETAs, ETAs and OMEGAs in the control stream
even if you do not use them. Try to add

Y=F+THETA(1)+ETA(1)+EPS(1)
$THETA
0 FIXED
$OMEGA
0 FIXED
$SIGMA
0 FIXED

instead of
Y=F

Also, you can get AUC much easier than by adding 560 points per subject:
re-write your system in terms of differential equations and add AUC
compartment


$DES

...
DADT(5)=A(2)/S2


Values of A(5) at any time is the AUC from time zero up to the current time

Thanks
Leonid

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




Hang, Yaming wrote:
> Dear NONMEM Users,
>
> I have a study where I'd like to predict AUC based on 2~3 trough
> concentrations. There are about 500 subjects and I intend to predict
> drug concentration for 560 time points for each subject (10 time
> points/day * 56 days). The EBE for model parameters for each individual
> have been generated and they will be fed into NONMEM for calculation of
> drug concentrations. The following is the relevant NONMEM code:
>
> $INPUT ID DOSE=DROP DAYN TIME AMT DV EVID MDV ADDL II CONC CLI V2I Q3I
> V3I Q4I V4I KAI F1I ALGI
>
> $SUBROUTINES ADVAN12 TRANS4
> $PK
> CL=CLI
> V2=V2I
> KA=KAI
> F1=F1I
> Q3=Q3I
> V3=V3I
> Q4=Q4I
> V4=V4I
> ALAG1=ALGI
> S2=V2I*624.709/1E6
>
> $ERROR
> IPRED=F
> Y=F
>
> $SIMULATION (26730517) ONLYSIMULATION SUBPROBLEMS=1
>
> But I get error message like
> *0WARNING: MAXIMUM NUMBER OF THETA'S PLUS VARIANCE COMPONENTS*
> * EXCEEDS MAXIMUM NUMBER OF PARAMETERS THAT CAN BE ESTIMATED.*
> * SEE INSTALLATION GUIDE*
>
> I've increased LTH to 60 in file SIZES, LVR has a value of 30, but still
> encounter this error message.
>
> Does anybody have done similar thing in the past? What's likely to be
> the true issue here? Your suggestion will be greatly appreciated.
>
> Yaming
>
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Received on Thu Feb 18 2010 - 00:16:34 EST

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