Discrete (plasma) parameters that are estimated when at steady-state
AUClower_upper: (Optional) User-requested area(s) under the curve from time “lower” to “upper.”
AUC_TAU: The partial area from dosing time to dosing time plus Tau. If dosing time plus Tau is not an exact observation time due to small sampling time deviations, the AUC is computed based on an estimated concentration at dosing time plus Tau, not on an actual concentration within a small sampling time deviation from dosing time plus Tau.
AUC_TAU_D: = AUC_TAU/Dose
AUC_TAU_%Extrap: Percentage of AUC_TAU that is due to extrapolation from Tlast to dosing time plus Tau.
= 
= 
AUMC_TAU: Area under the first moment curve from dosing time to dosing time plus Tau.
Cavg: Average concentration, computed = AUC_TAU/Tau
CLss, CLss_Fa: An estimate of the total body clearance, computed for IV Bolus and Infusion dosing only.
= 
Cmax: Maximum observed concentration, occurring at time Tmax, as defined below.
Cmin: Minimum observed concentration occurring at time Tmin as defined below.
Note: Regulatory agencies differ on the definition of Cmin: some agencies define Cmin the same as Ctau is defined below. Both Cmin and Ctau are included in the output so the correct parameter for the situation can be chosen.
Ctau: Concentration at dosing time plus Tau. Observed concentration if the value exists in the input data; otherwise, the predicted concentration value. Predicted concentrations are calculated following the same rules as for computing inserting missing endpoints needed for partial areas.
Fluctuation%: = 100[(Cmax – Cmin)/Cavg], where Cmin and Cmax were obtained between dosing time and dosing time plus Tau.
Fluctuation%_Tau: = 100[(Cmax – Ctau)/Cavg]
MRTINF(_obs, _pred): Mean residence time (MRT) extrapolated to infinity. For steady-state data:
For non-infusion: 
For infusion: 
where Tinf represents infusion duration. (Note that, for oral model 200, MRTINF includes Mean Input Time as well as time in systemic circulation.)
Swing: = (Cmax – Cmin)/Cmin
Swing_Tau: = (Cmax – Ctau)/Ctau
Tau: The (assumed equal) dosing interval for steady-state data. Available in the Dosing Used results for steady-state data.
Tmax: Time of maximum observed concentration. For steady-state data, based on observations collected during the dosing interval, that is, at or after the dosing time, but no later than the dosing time plus Tau, where Tau is the dosing interval. If the maximum observed concentration is not unique, then the first maximum is used.
Tmin: Time of minimum observed concentration. For steady-state data, based on observations collected during the dosing interval (i.e., after the dosing time, but no later than dosing time plus Tau, where Tau is the dosing interval). If the minimum observed concentration is not unique, then the first minimum is used.
Vss(_obs, _pred): An estimate of the volume of distribution at steady-state. Computed for IV Bolus and infusion dosing only.
= MRTINF(CLss)
Not computed for extravascular dosing (oral model 200), as MRTINF for oral models includes Mean Input Time as well as time in systemic circulation and therefore is not appropriate to use in calculating Vss.
Vz, Vz_Fa: For steady-state data: = 
aFor extravascular models (model 200), the fraction of dose absorbed cannot be estimated; therefore Volume and Clearance for these models are actually Volume/F or Clearance/F where F is the fraction of dose absorbed.