NONMEM Users Network Archive

Hosted by Cognigen

Re: Generating Cmax at end of infusion

From: Leonid Gibiansky <LGibiansky>
Date: Tue, 06 Apr 2010 13:07:34 -0400

Hi Paul,
You cannot use T in ADVAN3. ADVAN3 uses the exact solution to advance
between TIME points. If you include the end of infusion as EVID=2 time
point, you can get it there. Otherwise, I am not sure how to get hold on
the solution at that specific time. It could be possible, because the
end-of infusion should be (at least internally) the point to which the
system is advanced, but I do not know how to get data at that (internal)
point.

An easier way would be to rewrite the system in differential equations
(ADVAN6). Then you can get the solution at any time point T (in he $DES
block) but you will have to output it on the next TIME point.

Hope this helps
Leonid

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




Paul Hutson wrote:
> G'day.
> I would like to generate a concentration at the end of an infusion of
> duration DUR.
> I am using ADVAN3 TRANS4 with log transformed data. Here is what I
> have tried, but I am getting an error that the parameter 'T' that I
> understood to be the machine time is undefined. Can anyone suggest a
> proper way to give set Cmax=exp(Y) at the end of the infusion of length DUR?
> Many thanks in advance.
> Paul
> $PK
> ...
> TT=TIME
>
> $ERROR
> ;I've also tried
> ;TT=TIME
> ;TT=T
> IPRE=F
> EDV=EXP(DV)
> W=1
> IF(F.GT.0) W=F
> IRES=F-EDV
> IWRE=IRES/W
> LOGF=LOG(0.0001)
> IF (F.GT.0) LOGF=LOG(F)
> Y=LOGF+EPS(1)
> ;GENERATE CMAX AT END OF INFUSION (DUR)
> IF(DUR.EQ.TT) CMAX=EXP(Y)
> --
>
> Paul R. Hutson, Pharm.D.
>
> Associate Professor
>
> UW School of Pharmacy
>
> 777 Highland Avenue
>
> Madison WI 53705-2222
>
> Tel 608.263.2496
>
> Fax 608.265.5421
>
> Pager 608.265.7000, p7856
>
Received on Tue Apr 06 2010 - 13:07:34 EDT

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.