From: Fabrice Nollevaux fabrice_nollevaux@sgs.com
Subject: [NMusers] Simultaneous model of plasma and whole blood data
Date: Fri, August 6, 2004 11:10 am

Dear All, 

In our study, a drug has been determined in both plasma
and whole blood. 
How to simultaneously fit plasma and whole blood concentrations,
given the particularity that one compartment (plasma) is
included in the other (whole blood). 
Any NM-code example will be welcome. 

Moreover, drug levels are markedly lower in plasma than in whole
blood, indicating a significant uptake of the drug by blood cells. 
Separately, plasma and whole blood concentrations are both well
fitted using a three-compartmental mode, while we were expecting
to need one additional compartment for plasma related to blood cells. 
Many thanks in advance for any suggestion in the interpretation
of this situation. 

Fabrice Nollevaux, 
SGS Biopharma - Wavre - Belgium 
www.sgsbiopharma.com 
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From: "Bhattaram, Atul" BhattaramA@cder.fda.gov
Subject: RE:[NMusers] Simultaneous model of plasma and whole blood data
Date: Fri, August 6, 2004 2:33 pm


Hello
 
You can model both blood and plasma simultaneously. Include "TYPE"
as an indicator for blood or plasma and use them in the $ERROR
block as shown below:
 
$ERROR
  PL=A(1)/S1
  Q1=0
  IF (TYPE.EQ.2) Q1=1
  Y1= F*(1+ERR(1))+ERR(2)
  Q2=0
  IF (TYPE.EQ.1) Q2=1
  FAC=PL*SL
  Y2=FAC*(1+ERR(3))+ERR(4)
    
  Y=Q1*Y1+Q2*Y2
 
Hope this helps, 

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