Simply put, linear kinetics, dosage and pharmacokinetic parameters are linear, such as taking 1mg, cmax 10, taking 2mg, cmax 20, taking 4mg and Cmax 40. This is linear kinetics. However, nonlinear kinetics, pharmacokinetic parameters and dosage are not linear, such as 1mg, cmax 10, 2mg, 25 mg, 4mg and 60 mg.

This is very important in clinic. Considering the clinical safety, the range of pharmacokinetic parameters can be estimated simply by the dosage, but the nonlinear estimation is difficult.