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 #