NONMEM Users Network Archive

Hosted by Cognigen

Re: model dynamic data with $DES subroutine

From: Sam Liao <sliao>
Date: Thu, 03 Dec 2009 10:33:15 -0500

If you are using NONMEM v6 or later, add this line before $DES
A_0(1)= KIN/KOUT

Sam Liao
Pharmax Research
> Dear NMusers,
>
> I have a question I would like your help. The data I have is only the
> dynamic data since we didn't give dose to the animal. I am trying to
> capture the nature of disease progression. And the PD decrease with
> time. I have seen people model only the PD data use $PRED subroutine
> but they use the explicit equation.But I want to use a differential
> equation like dA/dt= kin(1-dis)-kout*A while A0=kin/kout.
>
> When I ran the control stream, the gradient for most of the parameters
> are 0. And the only parameter estimation I got is the sigma. The
> output of Y is 0. I guess it's because I don't have dose to
> compartment(PDK) but I don't know how should I fix the problem.
> Any suggestion is appreciated!
>
> The control stream I wrote is:
>
> $PROB Demo for turn over PD model
> $INPUT ID TIME AMT PDK=DV EVID
> $DATA demo.csv IGNORE=#
>
> $ESTIM MAXEVAL=3000 NOABORT PRINT=1
> METHOD=COND INTERACTION SIG=5 MSFO=save.msf
>
> $COV MATRIX=S SLOW
>
> $SUBROUTINE ADVAN6 TOL=5
>
> $MODEL
> COMP=(PDK)
>
> $PK
> KIN=THETA(1)*EXP(ETA(1))
> KOUT=THETA(2)
> DIS=THETA(3)*EXP(ETA(2))
>
> $DES
> DADT(1)=KIN*(1-DIS)-KOUT*A(1)
>
> $ERROR
> Y = F + ERR(1)
>
> ; Fixed effects
> $THETA 174 FIX ; KIN
> $THETA 77 FIX ; KOUT
> $THETA (0,0.28,1) ; AGE_EFFECT_PDK
>
> ; Random effects
> $OMEGA 0 FIX; BSVKIN_PDK
> $OMEGA 0 FIX; BSVDIS_PDK
>
>
> $SIGMA 0.1
>
>
> $TABLE ID TIME PDK Y
> NOPRINT ONEHEADER FILE=DEMO.fit
>
>
>
> And my data looks like:
> #ID TIME AMT PDK EVID
> 101 4 . 1.49 0
> 102 4 . 1.58 0
> 61 8 . 0.57 0
> 62 8 . 2.03 0
> 63 8 . 1.58 0
> 64 8 . 1.52 0
> 109 12 . 0.71 0
> 110 12 . 1.18 0
> 21 12 . 1.25 0
>
>
> -Jing
>
>
> This e-mail and any files transmitted with it, are intended solely for
> the use of the individual or entity to whom they are addressed.?If you
> have received this e-mail in error, please reply to this message and
> let the sender know.
>
>
>
> ------------------------------------------------------------------------
> Chat with Messenger straight from your Hotmail inbox. Check it out
> <http://www.microsoft.com/windows/windowslive/hotmail_bl1/hotmail_bl1.aspx?ocid=PID23879::T:WLMTAGL:ON:WL:en-ww:WM_IMHM_4:092009>
Received on Thu Dec 03 2009 - 10:33:15 EST

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to: nmusers-request@iconplc.com.

Once subscribed, you may contribute to the discussion by emailing: nmusers@globomaxnm.com.