This calculator converts clearance (CL) and volume (V) parameters for 2- and 3-compartment mammillary PK models to corresponding micro- and macro-rate constants. Enter CL, VC, Q1, VP1(and Q2, VP2for three-compartment models). Derived half-lives and VSSare also output.
This calculator converts clearance (CL) and volume (V) parameters for 2- and 3-compartment mammillary PK models to corresponding micro- and macro-rate constants. Derived half-lives and steady-state volume of distribution (VSS) are also output.
Overrides take the same units as the results they replace: volume for VSS, 1/time for rate constants, and time for half-lives.
Enter CL, VC, Q1, and VP1 to see the derived rate constants, half-lives, and VSS.
Note: Calculations follow clearance and volume-based two- and three-compartment model relationships. Optional overrides replace the computed values when provided. Unit selections label the inputs and results, they do not convert between units, so enter every value in the units you select; dimensions you leave unspecified read generically as "volume" and "time". Validate outputs against your model specification and assumptions before use.
Calculations are based on clearance and volume parameterizations of the classical 2- and 3-compartment mamillar models.
VSS = VC + VP1 (+ VP2)
k10 = CL / VC
k12 = Q1 / VC
k21 = Q1 / VP1
k13 = Q2 / VC (three-compartment)
k31 = Q2 / VP2 (three-compartment)
α, β (two-compartment) from the quadratic roots of the CL/V-based system
α, β, γ (three-compartment) from the cubic roots of the CL/V-based system
t1/2 = ln(2) / rate
Important:These equations match the CL/V-based models in thePKconverterpackage. Always validate with your team’s modeling conventions and assumptions.
Calculate exposures needed to achieve common effect thresholds based on simple or sigmoidal maximum effect (Emax) models.