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RE: Modeling concentration data with imprecise sampling time

From: Fidler,Matt,FORT WORTH,R&D <Matt.Fidler>
Date: Thu, 2 Jun 2011 11:10:41 -0500

Mike,

You could use a MIXTURE model to determine of the 1-hour nominal time point=
 is before or after the infusion.

$PK
        CALLFL=1
        EST=MIXEST
        IF (MIXNUM.EQ.2) THEN
          D1 = THETA(1)
        ELSE
          D1=THETA(2)
        ENDIF

...

$MIX
        P(1)=THETA(3)
        P(2)=1.-THETA(3)
        NSPOP=2

...


$THETA (0.9 FIXED) ; Duration of Infusion for Population #1

(1.1 FIXED) ; Duration of Infusion for Population #2
(0 0.5 1) ; Proportion of Population having sampled in infusion phase.








From: owner-nmusers
 Behalf Of mdkzone
Sent: Thursday, June 02, 2011 10:45 AM
To: nmusers
Subject: [NMusers] Modeling concentration data with imprecise sampling time


All:

   I have a data set following a constant rate 1-hour infusion where the ti=
me of 1-hour sample is imprecise. In some cases the "1-hr" sample was take=
n prior to infusion termination as it was intended; however, in others it w=
as quite apparently take after the infusion ended. I'm thinking of modelin=
g with the time of the "1-hr" sample as a "theta". Does anyone have a NONM=
EM coding example showing how to do this? Any other suggestions as to how =
to handle this would be appreciated as well.

Thanks,
Michael

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Received on Thu Jun 02 2011 - 12:10:41 EDT

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