Re: [NMusers] Numerical integreaion and change in clearance over time

From: Leonid Gibiansky <lgibiansky_at_quantpharm.com>
Date: Tue, 19 Dec 2017 20:52:40 -0500

One option is to run all analyses in analytical ADVANs and then re-run
the final model in differential equations. If the results are close, it
could be used as a justification of the final model. If not,
differential equations solution should be preferred, I guess. In our
experience, analytical solution is usually pretty close to the
differential equations but this may depend on the data (time step of
records). One option to increase precision is to place extra EVID=2
records, so that the time step is smaller. Another option is to use
MTIME for that, similar to:

https://www.page-meeting.org/default.asp?abstract=1361

Leonid

On 12/19/2017 6:15 PM, Pavel Belo wrote:
> Hello NONMEM Users,
>
> When clearance changes over time, the classic analytical solution for
> the 2-compartment linear model is not correct.  Nevertheless, if the
> change is only ~30%, one can say it is still acceptable.  Time required
> to run an analytical and numerical models is drastically different,
> which can be important for decision making.  Did someone  had an
> experience submitting using analytical solution when clearance changes
> over time to an agency or a journal?  Can it be acceptable?
>
> Thanks,
>
> Paul
>

Received on Tue Dec 19 2017 - 20:52:40 EST

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