Back to the Top
Dear PharmPK readers,
I am trying to deconvolute an extravascular profile of a drug whose
IV curve can be described by the triexponential equation: Conc(pg/mL)
= 450*exp(-2*t)+ 40*exp(-0.2*t)+ 5*exp(0.02*t) after a dose of
40000000 pg.
In trying to figure out the unit impulse response I divide the three
coefficients (450, 40, 5) by the dose, which produces ridiculously
small numbers. Is it OK to put these small numbers as different
values of the A term into WinNonlin during the deconvolution process?
I am also assuming that it is OK to put in the three exponents as
different values of alpha into WinNonlin.
Furthermore, the extravascular dose is not the same as the IV dose.
Is there a correction needed in WinNonlin to account for a different
doses.
Kindly advice,
M Samtani
Back to the Top
The following message was posted to: PharmPK
In my experience with the deconvolution engine within WinNonlin, you
must scale the IV coefficients (A and B) to be dose equivalent to the
extravascular dose. For example, if you have a 10 mg IV dose and a 50 mg
oral dose, multiply A and B by 5 and use those values in the WinNonlin
input sheet.
This is different from other software such as PCDCON or spreadsheets
where the unit dose can be used for the IV parameters.
Nathan Teuscher
--
Nathan S. Teuscher, Ph.D.
Associate Director, PK/PD and Pharmacometrics
MDS Pharma Services
Tel: (402) 437-6332
Cell: (402) 617-7207
Fax: (402) 476-7598
Email: Nathan.Teuscher.at.mdsinc.com
PharmPK Discussion List Archive Index page
Copyright 1995-2010 David W. A. Bourne (david@boomer.org)