R: Calculate derived parameters for the 1-, 2-, and 3-...

rxDerived {RxODE} | R Documentation

## Calculate derived parameters for the 1-, 2-, and 3- compartment linear models.

### Description

This calculates the derived parameters based on what is provided in a data frame or arguments

### Usage

    rxDerived(..., verbose = FALSE, digits = 0)

### Arguments

`...` | The input can be: A data frame with PK parameters in it; This should ideally be a data frame with one pk parameter per row since it will output a data frame with one PK parameter per row. PK parameters as either a vector or a scalar
`verbose` | boolean that when TRUE provides a message about the detected pk parameters and the detected compartmental model. By default this is `FALSE`.
`digits` | represents the number of significant digits for the output; If the number is zero or below (default), do not round.

### Value

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

The model parameters that will be provided in the data frame are:

- `vc`: Central Volume (for 1-, 2- and 3- compartment models)

- `kel`: First-order elimination rate (for 1-, 2-, and 3-compartment models)

- `k12`: First-order rate of transfer from central to first peripheral compartment; (for 2- and 3-compartment models)

- `k21`: First-order rate of transfer from first peripheral to central compartment, (for 2- and 3-compartment models)

- `k13`: First-order rate of transfer from central to second peripheral compartment; (3-compartment model)

- `k31`: First-order rate of transfer from second peripheral to central compartment (3-compartment model)

- `vp`: Peripheral Volume (for 2- and 3- compartment models)

- `vp2`: Peripheral Volume for 3rd compartment (3- compartment model)

- `vss`: Volume of distribution at steady state; (1-, 2-, and 3-compartment models)

- `t12alpha`: t_{1/2,α}; (1-, 2-, and 3-compartment models)

- `t12beta`: t_{1/2,β}; (2- and 3-compartment models)

- `t12gamma`: t_{1/2,γ}; (3-compartment model)

- `alpha`: α; (1-, 2-, and 3-compartment models)

- `beta`: β; (2- and 3-compartment models)

- `gamma`: β; (3-compartment model)

- `A`: true `A`; (1-, 2-, and 3-compartment models)

- `B`: true `B`; (2- and 3-compartment models)

- `C`: true `C`; (3-compartment model)

- `fracA`: fractional A; (1-, 2-, and 3-compartment models)

- `fracB`: fractional B; (2- and 3-compartment models)

- `fracC`: fractional C; (3-compartment model)

### Author(s)

Matthew Fidler and documentation from Justin Wilkins, justin.wilkins@occams.com

### References

Shafer S. L. `CONVERT.XLS`

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

### Examples

    ## Note that RxODE parses the names to figure out the best PK parameter

    params <- rxDerived(cl = 29.4, v = 23.4, Vp = 114, vp2 = 4614, q = 270, q2 = 73)

    ## That is why this gives the same results as the value before

    params <- rxDerived(CL = 29.4, V1 = 23.4, V2 = 114, V3 = 4614, Q2 = 270, Q3 = 73)

    ## You may also use micro-constants alpha/beta etc.

    params <- rxDerived(k12 = 0.1, k21 = 0.2, k13 = 0.3, k31 = 0.4, kel = 10, v = 10)

    ## or you can mix vectors and scalars

    params <- rxDerived(CL = 29.4, V = 1:3)

    ## If you want, you can round to a number of significant digits
    ## with the `digits` argument:

    params <- rxDerived(CL = 29.4, V = 1:3, digits = 2)

[Package RxODE version 1.1.2 Index]