1 reply to this topic

[Vickie Driver]

Should the HL_lambda z be the same as MRT in a NCA PK data? What is the relationship of MRT to half life?

Thanks

Vickie

[Simon Davis]

Hi Vickie,
No they are not the same parameter; please take a look at the software's help e.g. srearch for MRT and go to the section NCA output parameters and their computation formulas

MRTlast Mean residence time from the time of dosing (Dosing_time) to the time of the last measurable concentration. For non-infusion models: MRTlast = AUMClast/AUClast. For infusion models: MRTlast = (AUMClast/AUClast) - TI/2.

whereas

HL_Lambda_z Terminal half-life = ln(2)/lamda_z

In a one-compartment model following i.v. administration the mean residence time (MRT) of a drug is always greater than its half-life (t1/2)

Also I would like to inform all the board readers that the Validation Suited for Phoenix WinNonlin was released this week - have a great week end everybody ;0)

Best regards,
Simon.
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