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
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) [size=4][color=#FF0000]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[/color] ;0)[/size] Best regards, Simon. ___________________________________ Forthcoming meetings and training -Certara | Drug Development Solutions; Transitioning to Phoenix NLME v6.1: 8 June 2010 Berlin, Germany (prior to PAGE). Transitioning to Phoenix v6.1: 6 Sept 2010, Amsterdam, Holland. Introduction to Phoenix v6.1: 7-9 Sept 2010, Amsterdam, Holland.