Lixoft is providing model libraries to simplify the use of its software. The mathematical expressions of the pharmacokinetic and pharmacodynamic models implemented in MonolixSuite can be found here: PKPDlibrary

### Pharmacokinetic models

The equations in the ensuring chapter describe the pharmacokinetic models implemented in the MonolixSuite software. The presentation of the models is organised as follows:

- First level: number of compartment
- One compartment
- Two compartments
- Three compartments

- Second level: route of administration
- IV bolus
- Infusion
- First order absorption
- Zero order absorption

- Third level: elimination process
- Linear
- Michaelis-Menten

- Fourth level: existence of a lag time for first and zero order absorption only

The equations express the concentration C (t) in the central compartment at a time t after the last drug administration.

*Single dose:*at time t after dose D given at time*Multiples doses*: at time t after n doses for i from 1 to n given at time*Steady state*: at a time t after dose D given at time after repeated administration of dose D given at interval (only for linear elimination)

### Pharmacodynamic models

A lot of pharmacodynamical models are also proposed with MonolixSuite software. Some of these pharmacodynamic models can be used alone or linked to any pharmacokinetic model. Some can only be used linked to any pharmacokinetic model. Two different type of models are presented here:

- The immediate response models (alone or linked to a pharmacokinetic model)
- The turnover models (only linked to a pharmacokinetic model)

Any combination drug action models and baseline/disease models is available are also available.