NONMEM Users Network Archive

Hosted by Cognigen

Re: When is F1 Evaluated

From: Nick Holford <n.holford>
Date: Fri, 10 Apr 2009 21:52:21 +0200


F1 is evaluated at the instant that AMT enters CMT=1.

If you want to modify F during absorption you will need to use something
like this:

DADT(1) = -KA*A(1) ; gut loss (F1 will affect the AMT entering this CMT
at the time of AMT record)
FT=a+ b*A(1) ; some function of amount in CMT=1
DADT(2) = FT*KA*A(1) - CL*A(2)/V ; FT is a time varying fraction of the
rate entering CMT=2


Denney, William S. wrote:
> Hello,
> When is F1 evaluated? I am working on a model with nonlinear
> bioavailability and I need to know if F1 is evaluated during the
> entire absorption process or if it is evaluated upon the dose entering
> the dosing compartment.
> Thanks,
> Bill
> Notice: This e-mail message, together with any attachments, contains
> information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station,
> New Jersey, USA 08889), and/or its affiliates (which may be known
> outside the United States as Merck Frosst, Merck Sharp & Dohme or
> MSD and in Japan, as Banyu - direct contact information for affiliates is
> available at that may be
> confidential, proprietary copyrighted and/or legally privileged. It is
> intended solely for the use of the individual or entity named on this
> message. If you are not the intended recipient, and have received this
> message in error, please notify us immediately by reply e-mail and
> then delete it from your system.

Nick Holford, Dept Pharmacology & Clinical Pharmacology
University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand
mobile: +33 64 271-6369 (Apr 6-Jul 17 2009)

Received on Fri Apr 10 2009 - 15:52:21 EDT

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to:

Once subscribed, you may contribute to the discussion by emailing: