NONMEM Users Network Archive

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RE: [NMusers] Calculation of half life

From: Pavel Belo <nonmem_at_optonline.net>
Date: Wed, 30 Mar 2016 13:34:57 -0400 (EDT)


 You can add formulas to NONMEM code.  All individual noncompartm=
ental
parameters can be calculated within NONMEM.  An example of the NONMEM=
 
code is below.  tH
 
  DADT(6) = A(8) ;calculates AUC if A is concentration
  DATD(8) = [put here the right part of the differential equation wh=
ich
calculates concentration]
 
  CONC=A(8)
  AUC =A(6)
  AUCT=A(12)
 



  IF (CONC.GT.1E-20) THEN


    LAM=-([put here the right part of the
differential equation which calculates concentration]/CONC


  ELSE


    LAM=666666666


  ENDIF


 


  IF (AUC.GT.1E-20) THEN


    MRT=AUCT/AUC


  ELSE


    MRT=666666666;


  ENDIF


 


  IF (AUC.GT.1E-20.AND.MWT.GE.0.000001) THEN


    CL =DKG*BIO/(AUC*MWT)


  ELSE


    CL =666666666


  ENDIF


 


  VSS=MRT*CL


 


  IF (DABS(LAM).GT.1E-20) THEN


    IHL=0.693147/LAM


  ELSE


    LAM=666666666


    IHL=666666666


  ENDIF


 


  IF (DABS(LAM).GT.1E-10.AND.AUC.GE.1E-10) THEN


    VZ =DKG*BIO/(LAM*AUC*MWT)


  ELSE


    VZ =666666666


  ENDIF


 


 


  AQ=1;  



  BQ=K23+K32+KED;  


  CQ=K32*KED;


  DQ=BQ**2-4*AQ*CQ; 


  BET2=666666666


  IF (DQ.GE.0) BET2=(-BQ+SQRT(DQ))/(2*AQ);


 


  BHLK= KED*(K32/(K32 + K23))


 


  IF (BET2.LT.-1E-10) THEN


    BHL=-LOG(2)/BET2;  


  ELSE


    BHL=666666666


  ENDIF


 


  IF (DABS(A1).GE.1E10) A1=6666666


  IF (DABS(A2).GE.1E10) A2=6666666


  IF (DABS(A3).GE.1E10) A3=6666666


  IF (DABS(A4).GE.1E10) A4=6666666


  IF (DABS(A5).GE.1E10) A5=6666666


  IF (DABS(IHL).GE.1E10) IHL=6666666


  IF (DABS(MRT).GE.1E10) MRT=6666666


  IF (DABS(CL).GE.1E10) CL=6666666


  IF (DABS(VSS).GE.1E10) VSS=6666666


  IF (DABS(LAM).GE.1E10) LAM=6666666


  IF (DABS(VZ).GE.1E10) VZ=6666666


  IF (DABS(BHL).GE.1E10) BHL=6666666


  IF (DABS(BHLK).GE.1E10) BHLK=6666666


 
 
On Wed, Mar 30, 2016 at 11:40 AM, Santosh wrote:
 
 

Dear all, 
I am looking for ways to calculate t[1/2,lamda,z] the elimination phase
half life, using  a 3-compartment model. ADVAN 12 and TRANS6 seems to =
be
a way. However, I am using the intercompartment clearance and volumes
based parameterization, e.g. Q3,V3 etc..


half.life = log(2)/gamma


Could anyone please share NONMEM code to compute the half-life based on
gamma?


Thanks so much in advance.


Best regards,
Santosh



Received on Wed Mar 30 2016 - 13:34:57 EDT

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