Structural Model | |
(1a) Single Hill model | E = B + (Econ − B) (Cγ/(Cγ +IC50 γ)) |
(1b) Double Hill model | E = B+ (Econ + GROW − Econb)(Cγa/(Cγa +IC50a γa)) + (Econb − B)(Cγb/(Cγb + IC50b γb) |
Pattern of Change of Parameters | |
IC50parameter | |
(2a) Constant IC50 | IC50 = Constant |
(2b) ICx n T model | IC50 = (K/T) |
(2c) Sigmoid model | IC50 = IC50back +(IC50max − IC50back)(Ts/(Ts +T50 s)) |
Slope parameter γ | |
(3a) Constant γ | γ = γ0 |
(3b.I) Linear model | IF (T < 24) γ = γ0(24 − T)/24 + γ1(T/24) |
IF (T > 24) γ = γ1(72 − T)/48 + γ2(T/48) | |
(3b.II) Linear model | IF (T < 28) γ = γ0(28 − T)/28 +γ1(T/28) |
IF (T > 28) γ = γ1(72 − T)/44+ γ2(T/44) | |
Plateau parameters | |
(4a) Exponential model for Econ | Econb = Econ1e−k eT |
E, cell survival in percentage of control; B, cell survival at infinite drug concentration (the plateau of the concentration-effect curve); Econ, control cell survival at zero drug concentration; C, drug concentration; IC50, concentration of drug resulting in 50% inhibition of the maximal effects (Econ − B); γ, slope parameter of a single Hill concentration-effect curve; Econb, cell survival at the first plateau of a double Hill curve; GROW, increase in the cell survival more than 100% at lower concentrations;γa, slope parameter of the upper part of the concentration-effect curve; γb, slope parameter of the lower part of the double Hill concentration-effect curve; IC50a, concentration of drug resulting in 50% inhibition of the effect (Econ − Econb); IC50b, concentration of drug resulting in 50% inhibition of the effect (Econb − B); ICx, concentration of the drug resulting in x% inhibition in the maximal effect (Econ − B); n, concentration coefficient. T, exposure duration to a drug; K, exposure constant; IC50back, IC50 at zero exposure time to a drug; IC50max, IC50 at infinite exposure time to a drug; S, slope parameter of the time − IC50 curve; T50, exposure duration resulting in 50% decrease of the IC50; γ0, γ1, γ2, slope of the concentration-effect curve at 0′, X′, and 72-h exposure; ke, rate constant of decrease of Econb; Econ1, Econb at zero exposure time.