Example - Variations in models using Propofol data

Variations in models using Propofol data

The data in propofol.dat follows a three compartment pharmacokinetic model with IV infusion input. This example uses a model similar to the compiled Least-Squares Regression PK model number 19.

Note:The completed project (Propofol.phxproj) is available for reference in …\Examples\NLME.

Set up the Maximum Likelihood Models object

Create a new project called Propofol.
Import the dataset …\Examples\NLME\Supporting files\propofol.dat.
Click Finish in the File Import Wizard.
Right-click the propofol worksheet in the Data folder and select Send To > Modeling > Maximum Likelihood Models.
In the Structure tab of the ML Model object, select Macro1 from the Parameterization menu.
In the Num Terms menu, select 3.
Check the Infusions possible? checkbox.
In the Residual Error model menu, select Multiplicative.
Type 0.3 in the Stdev field.
Select the Parameters > Fixed Effects sub-tab.
In the Initial column, enter the following initial estimates for each of the study parameters:
tvV = 11
tvAlpha = 0.38
tvB = 0.07
tvBeta = 0.03
tvC = 0.004
tvGamma = 0.002
Select the Random Effects sub-tab.
Type 0.1 in the Initial Estimates fields for nV, nAlpha, nB, nBeta, nC, and nGamma.
Select the Run Options tab.
In the Algorithm menu, select Naive pooled.
Select Forward Diff in the Stderr menu.

Map the model variables

Select the option buttons in the Main Mappings panel to map the data types as follows:
TID to the ID context.
ID to the None context. ID cannot be mapped to the ID context.
TIME to the Time context.
DV to the C1Obs context.
RATE to the A Rate context.
AMT to the A context.
All other data types mapped to None.
Click (Execute icon) to execute the object.

Accept the new initial estimates

Select the Parameter > Fixed Effects sub-tab.
Click Accept All Fixed+Random to copy the new estimates to the Initial estimates field for each parameter.
Select the Run Options tab.
In the Algorithm menu, select FOCE L-B.
Execute the object.

Save and close the project

Select File > Save Project.
Click Save.
Select File > Close Project.

The project is saved and closed and Phoenix can be safely exited.

This concludes the model variations using propofol data example.