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I would like to know which WinNonlin model should be used if we have
the data of Time and plasma conc after the application of a
transdermal patch if we want to characterize the pk parameters and
the model for the same.
thanking you in anticipation.
Shobha Rani, M.Pharm,Ph.D
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Shoba - Many times the absorption kinetics of a transdermal patch can
be described by a model with zero-order input ('infusion model') with
the infusion duration set to the time the patch is worn. However,
there are many more cases where transdermal absorption is complicated
by a lag time before absorption occurs, residual absorption from the
skin depot after the patch is removed, and non-uniform absorption
profiles. Finally, the selection of a model also depends upon the
disposition kinetics of the drug.
While I cannot suggest an all-purpose library model for this
pharmacokinetic problem, I can make some suggestions.
Characterize the disposition kinetics of the drug (iv is always best
if you have it)
Perform deconvolution on the transdermal absorption data (this can be
done in WinNonlin, Professional)
Examine the absorption profile as predicted from deconvolution
Propose an absorption model
Fit the absorption data and iv data (if available) simultaneously
using the model from the previous step to account for the transdermal
If you have specific questions about the operation of WinNonlin or
its application please feel free to write a note to
support.-at-.pharsight.com for technical assistance.
Kind regards, Jeff Wald
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