pmxTools (version 1.2.1)

calc_derived: Calculate derived pharmacokinetic parameters for a 1-, 2-, or 3-compartment linear model.

Description

Calculate derived pharmacokinetic parameters for a 1-, 2-, or 3-compartment linear model.

Usage

calc_derived(..., verbose = FALSE)
calc_derived_1cpt(
  CL,
  V = NULL,
  V1 = NULL,
  ka = NULL,
  tlag = NULL,
  type = "all",
  sigdig = 5
)
calc_derived_2cpt(
  CL,
  V1 = NULL,
  V2,
  Q2 = NULL,
  V = NULL,
  Q = NULL,
  ka = NULL,
  tlag = NULL,
  type = "all",
  sigdig = 5
)
calc_derived_3cpt(
  CL,
  V1 = NULL,
  V2,
  V3,
  Q2 = NULL,
  Q3,
  V = NULL,
  Q = NULL,
  ka = NULL,
  tlag = NULL,
  type = "all",
  sigdig = 5
)

Arguments

...

Passed to the other calc_derived_*() functions.

verbose

For calc_derived(), provide a message indicating the type of model detected.

CL

Clearance (volume per time units, e.g. L/h)

V1, V

Central volume of distribution (volume units, e.g. L). Values are synonyms; use only one.

ka

Absorption rate (inverse time units, e.g. 1/h)

tlag

Absorption lag time (time units, e.g. h)

type

Parameters to return. Default is "all". If not "all", this may be a vector from the names of the return value list.

sigdig

Number of significant digits to be returned. Default is 5.

V2

First peripheral volume of distribution (volume units, e.g. L)

Q2, Q

Intercompartmental clearance from central to first peripheral compartment (volume per time units, e.g. L/h). Values are synonyms; use only one.

V3

Second peripheral volume of distribution (volume units, e.g. L)

Q3

Intercompartmental clearance from central to second peripheral compartment (volume per time units, e.g. L/h)

Value

Return a list of derived PK parameters for a 1-, 2-, or 3-compartment linear model given provided clearances and volumes based on the type.

• Vss: Volume of distribution at steady state, \(V_{ss}\) (volume units, e.g. L); 1-, 2-, and 3-compartment

• k10: First-order elimination rate, \(k_{10}\) (inverse time units, e.g. 1/h); 1-, 2-, and 3-compartment

• k12: First-order rate of transfer from central to first peripheral compartment, \(k_{12}\) (inverse time units, e.g. 1/h); 2- and 3-compartment

• k21: First-order rate of transfer from first peripheral to central compartment, \(k_{21}\) (inverse time units, e.g. 1/h); 2- and 3-compartment

• k13: First-order rate of transfer from central to second peripheral compartment, \(k_{13}\) (inverse time units, e.g. 1/h); 3-compartment

• k31: First-order rate of transfer from second peripheral to central compartment,\(k_{31}\) (inverse time units, e.g. 1/h); 3-compartment

• thalf_alpha: \(t_{1/2,\alpha}\) (time units, e.g. h); 1-, 2-, and 3-compartment

• thalf_beta: \(t_{1/2,\beta}\) (time units, e.g. h); 2- and 3-compartment

• thalf_gamma: \(t_{1/2,\gamma}\) (time units, e.g. h); 3-compartment

• alpha: \(\alpha\); 1-, 2-, and 3-compartment

• beta: \(\beta\); 2- and 3-compartment

• gamma: \(\beta\); 3-compartment

• trueA: true A; 1-, 2-, and 3-compartment

• trueB: true B; 2- and 3-compartment

• trueC: true C; 3-compartment

• fracA: fractional A; 1-, 2-, and 3-compartment

• fracB: fractional B; 2- and 3-compartment

• fracC: fractional C; 3-compartment

The input parameters with standardized names (V1, V2, V3, CL, Q2, and Q3) are also returned in the list, and if provided, additional PK parameters of `ka` and `lag` are also returned in the list. All inputs may be scalars or vectors.

References

Shafer S. L. CONVERT.XLS

Rowland M, Tozer TN. Clinical Pharmacokinetics and Pharmacodynamics: Concepts and Applications (4th). Lippincott Williams & Wilkins, Philadelphia, 2010.

Examples

# NOT RUN {
params <- calc_derived(CL=29.4, V1=23.4, V2=114, V3=4614, Q2=270, Q3=73)
params <- calc_derived_1cpt(CL=16, V=25)
params <- calc_derived_2cpt(CL=16, V1=25, V2=50, Q=0.5)
params <- calc_derived_3cpt(CL=29.4, V1=23.4, V2=114, V3=4614, Q2=270, Q3=73)
# }