# Also in the Article

Random effects model
This protocol is extracted from research article:
Population pharmacokinetic modeling of intramuscular and oral dexamethasone and betamethasone in Indian women
J Pharmacokinet Pharmacodyn, Jan 3, 2021;

Procedure

The interindividual variability (IIV) with the log-normal distribution was allowed for parameters:

where $θP$ is a typical value of parameter $P$, $ηP$ denotes its individual realization, and $ωP2$ is the variance in the log-domain. Selection of IIV parameters for the final model started with variances for $CL/FIM$, $Vp/FIM$ and increasing their number until either the estimation failed, precision of estimates were unacceptable, or goodness of fits plots were aberrant.

The observed drug plasma concentrations $Cij$ were log-transformed and the constant residual error model was applied:

where $tij$ is the $jth$ observation time for the $ith$ subject and $σ2$ is the variance of the residual error $εi$ that was same for all subjects.

Note: The content above has been extracted from a research article, so it may not display correctly.

Q&A