Table 1.

Properties of the presented CETs

CET	Equation	Construction principle	Symmetry	Positivity	Scaling	Diagonality	Maximal combination effect EmaxAB	Inhibitory form
Competitive	Equation (18)	DRBKa	Yes	Yes	Yes	Yes	max {EmaxA;EmaxB}	Yes
Uncompetitive	Equation (22)	DRBKa	No	Yes	Yes	–	(1+ β′)EmaxA	Yes for β′ ≤ 0
Non-competitive	Equation (24)	DRBKa	No	Yes	Yes	–	(1+ β′)EmaxA	Yes for β′ ≤ 0
Loewe	Equation (29)	ADDb	Yes	Yes	Yes	Yes	Emax	Yes
Bliss	Equation (33)	ADDb	Yes	Yes	Yes	Yes	Emax	Yes
Greco	Equation (37)	ADDb	Yes	No	Yes	Yes	Emax	Yes
Summation	Equation (39)	EmpSUMc	Yes	Yes	Yes	No	EmaxA + EmaxB	No
Inhibitory	Equation (42)	IDRd	Yes	Yes	No	No	ImaxA + ImaxB − ImaxAImaxB	–
Stimulation	Equation (43)	IDRd	Yes	Yes	No	No	EmaxA + EmaxB + EmaxAEmaxB	No

^aDrug-receptor binding kinetics

^bAdditive approaches

^cEmpirical summation approaches

^dIndirect response models