basic PK model for iv administration








[LONGITUDINAL]
input = {V, k}

PK:
depot(target=Ac)

EQUATION:
ddt_Ac = -k*Ac
Cc=Ac/V
setwd(dirname(parent.frame(2)$ofile))
library(ggplot2)

#-------------------------------------


adm <- list(time=3, amount=40)
Cc  <- list(name='Cc',time=seq(from=0, to=20, by=0.1))
p   <- list(name=c('V','k'), value=c(10,0.4))
res <- simulx(model='pk1_model.txt', parameter=p, output=Cc, treatment=adm)

plot1=ggplot(data=res$Cc, aes(x=time, y=Cc, group=id)) + geom_line(size=1) 
print(plot1)

One compartment model for intravenous administration

The amount \(A_c\) in the central compartment is solution of the ODE \(\ \ \dot{A_c}(t) = - k \, A_c(t)\)

The concentration \(C_c\) in the central compartment is defined by \(\ \ C_c(t) = A_c(t)/V\)

  • Define the dosage regimen in the tab iv: time of first dose, number of doses, interdose interval, infusion time, amount.

  • select the PK parameters in the tab parameters:
    • \(k\), the elimination rate constant,
    • \(V\), the volume of the central compartment.

  • define the outputs in the tab outputs :
    • select the output to display: the amount \(A_c\) or the concentration \(C_c\),
    • select the time range where the prediction is computed,
    • select the number of time points of the grid where the prediction is computed.

  • set some settings in the tab settings: line width, linear or semi-log scale.