Lec 3 Half-life, Elimination Rate, and AUC (End Exam 1, begin Exam 2)
K
elimination rate constant
t
time difference btwn C1 and C2
AUC = ?
AUC = Div / CL -if non-IV, consider F units = mg/L x hr
Rounding: K
3 sig fig
Area of a trapezoid formula
Area = ave. height x base
BEGIN EXAM 2 MATERIAL
BEGIN EXAM 2 MATERIAL
AUC t last
C last / K
Solve for C1
C1 = C2 / e ^(-Kt) = C2 * e ^(Kt)
Solve for C2
C2 = C1e ^(-Kt)
CL = ?
CL = Div / AUC
K = ?
K = CL/V CL and V are independent parameters (eg CL rate decreases if given an enzyme inhibitor) K is the dependent parameter (drug concen vs time -> resulting K) -increase Vd does NOT necess. mean CL increases b/c it does not change its capacity
Solve for K
K = ln(C1/C2) / t
Half-life equation
T 1/2 = 0.693 / K
AUC
area under the curve, total body exposure
Half-life
time necessary for concentration of drug in the body to be decreased by on-half
C1
larger concentration (aka Co)
y = mx + b for log graph curve equation
ln Cp = (slope * time) + ln Co ln Cp = (-elim. rate * time) + ln Co Hence: lnC2 = lnC1 - Kt
C2
smaller concentration
Solve for t
t = ln(C1/C2) / K
Rounding: L/hr
tenths
Rounding: All else
tenths *for using value for another calculation, carry 3 sig fig
Rounding: mL/min
whole #