L6
Zero order First order
Constant amount or rate of the drug Constant percentage of the drug
Definition per unit time (Linear relation with natural Log conc
(Linear relation with conc vs time) vs time)
Reaction dA/dt =-k0 dA/dt =-k0 × A
Curve of
Log 2.303
elimination
Dependency
on No Yes (rate limiting)
Concentration
Saturation Yes No
Speed or
velocity
Slower Faster
A = A0 × e-k × t
➢
➢ lnA = lnA0 – k0 × t
Equation A = A0 – k0 × 𝒕 −𝐤𝟎 × 𝐭
➢ LogA = LogA0 ×
𝟐.𝟑𝟎𝟑
Unit mg/hr or mg.hr-1 hr-1
Drug
decreasing
Linearly with time Exponentially with time
Rate of
k0 = Proportional to drug
elimination k0 = Constant
(k0) conc
t𝟏⁄𝟐 No true (depend on conc) Constant
Zero order First order
Constant amount or rate of the drug Constant percentage of the drug
Definition per unit time (Linear relation with natural Log conc
(Linear relation with conc vs time) vs time)
Reaction dA/dt =-k0 dA/dt =-k0 × A
Curve of
Log 2.303
elimination
Dependency
on No Yes (rate limiting)
Concentration
Saturation Yes No
Speed or
velocity
Slower Faster
A = A0 × e-k × t
➢
➢ lnA = lnA0 – k0 × t
Equation A = A0 – k0 × 𝒕 −𝐤𝟎 × 𝐭
➢ LogA = LogA0 ×
𝟐.𝟑𝟎𝟑
Unit mg/hr or mg.hr-1 hr-1
Drug
decreasing
Linearly with time Exponentially with time
Rate of
k0 = Proportional to drug
elimination k0 = Constant
(k0) conc
t𝟏⁄𝟐 No true (depend on conc) Constant
