2. 1. Cmax
This is the maximum drug concentration achieved in systemic circulation
following drug administration.
2. Cmin
This is the minimum drug concentration achieved in systemic circulation
following multiple dosing at steady state.
3. Cpd
This is the pre-dose concentrations determined immediately before a dose
is given at steady state.
4. Tmax
It is the time required to achieve maximum drug concentration in systemic
circulation.
3. 5. AUC0-t
Area under the plasma concentration - time curve from 0 h to the last
quantifiable concentration to be calculated using the trapezoidal rule.
6. AUC0-∞
Area under the plasma concentration - time curve, from zero to infinity to
be calculated as the sum of AUC0-t plus the ratio of the last measurable
concentration to the elimination rate constant.
7. AUC0-τ
Area under the plasma concentration - time curve over one dosing interval
following single dose for modified release products.
8. AUC0-τ(ss)
Area under the plasma concentration - time curve over one dosing interval
in multiple dose study at steady state.
4. 9. Kel
Apparent first-order terminal elimination rate constant calculated from a semi-log
plot of the plasma concentration versus time curve.
10. T1/2
Elimination half life of a drug is the time necessary to reduce the drug
concentration in the blood, plasma, or serum to one-half after equilibrium is
reached.
SYMBOLS
D = dose
τ = dosing interval
CL = clearance
Vd = volume of distribution
ke = elimination rate constant
ka = absorption rate constant
F = fraction absorbed (bioavailability)
K0 = infusion rate
