Re: Modeling concentration data with imprecise sampling time
Dear Janet,
I am not sure that tscale parameter would allow you to change the observation time relative to the end-of-infusion time. As stated in the manual, this parameter multiplies all rate constants (and only in linear models). "The time scale parameter does not scale the duration parameter D of a duration-modeled zero-order bolus dose." I assume it also does not change RATE value. Thus, it may change rates (internal individual times) but not the record times (or their relative positions).
Thanks
Leonid
--------------------------------------
Leonid Gibiansky, Ph.D.
President, QuantPharm LLC
web: www.quantpharm.com
e-mail: LGibiansky at quantpharm.com
tel: (301) 767 5566
Quoted reply history
On 6/3/2011 2:19 AM, Janet R. Wade wrote:
> Dear Michael
>
> I think you might want to use TSCALE (can also be written as XSCALE).
> This PREDPP parameter lets you scale time, and you can also add an eta
> (should you wish). The parameter is described in Guide VIII (Feb 2010).
> With appropriate IF statements you should be able to scale the time
> around the 1 hr time point only.
>
> Kind regards
>
> Janet
>
> *From:*[email protected]
> [mailto:[email protected]] *On Behalf Of *[email protected]
> *Sent:* 02 June 2011 17:45
> *To:* [email protected]
> *Subject:* [NMusers] Modeling concentration data with imprecise sampling
> time
>
> All:
>
> I have a data set following a constant rate 1-hour infusion where the
> time of 1-hour sample is imprecise. In some cases the "1-hr" sample was
> taken prior to infusion termination as it was intended; however, in
> others it was quite apparently take after the infusion ended. I'm
> thinking of modeling with the time of the "1-hr" sample as a "theta".
> Does anyone have a NONMEM coding example showing how to do this? Any
> other suggestions as to how to handle this would be appreciated as well.
>
> Thanks,
>
> Michael