Re: Predict AUC based on trough concentrations
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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