CA settings

The following page describes all the settings for the parameters calculations.


From the 2023 version of PKanalix, it is possible to use models from PK, PD, PKPD, PK Double Absorption, Parent Metabolite, TMDD and TGI libraries, as well as custom models, written in Mlxtran language. Option to define the model to use in compartmental analysis is available in the Model tab.

Left part of the Model tab shows the model file path and the Mlxtran code of the model file. The right part of the tab provides the option to map outputs of the model file to outputs present in the data set. Mapping is done by dragging and dropping the circles representing model and data outputs.

To use library models, in the CA Model tab click on Load from library and select the desired library. It is then possible to filter the list of models appearing on the bottom part of the window by using filters in the top part. After clicking on the model in the model list, the model will be applied.

More details about all the available models, including the full equations of each model, can be found on the dedicated page for the model libraries.

To use custom models, a text file that contains a pre-written model in the Mlxtran language can be selected by clicking on the Browse… button, new model can be written directly in the interface by clicking on the New model button, or already loaded model can be edited by clicking on the Edit model button.

In the versions prior to the 2023 version, it was only possible to use PK models from the MonolixSuite library in compartmental analysis.


Calculations settings

In the Run tab, there is an option to define initial parameters. To evaluate graphically the impact of these parameters, you can go to the “Check Init.” tab.

In addition to initial parameter values, there are several other settings impacting the calculation of the CA parameters available in the Run tab.

  • Cost function: Type of cost function. Possible options are (Ypred – Yobs)², (Ypred – Yobs)² / Yobs, (Ypred – Yobs)² / Ypred, (Ypred – Yobs)² / Yobs², (Ypred – Yobs)² / Ypred² and (Ypred – Yobs)² / |Ypred * Yobs| (default).
  • Pool fit: If FALSE (default), fit is with individual parameters or, if TRUE, with the same parameters for all individuals.
  • Method for BLQ: Method to replace the BLQ data. Possible options are: “zero”, “LOQ”, “LOQ/2” or “missing” (default value is “missing”).

In the versions prior to the 2023 version, Weighting option was available, instead of the Cost function option.