Page 58 - Interactive Theoritical Notes of Bioharmaceutics and pharamcokinetics.docx compressed

PharmD clinical pharmacy program Level 3, Semester 2 Biopharmaceutics & Pharmacokinetics (PT608(

 Two methods permit us to compute some pharmacokinetic parameters from urinary

excretion data:

The amount remaining to be excreted

Rate of urinary excretion method
Method method (ARE, Sigma-minus method).

Curve

Slope= - K
Slope = - K 0

Intercept = Du Intercept = ke DB



log (Du - Du) = log Du - Kt/2.3 log dDu /dt = log ke DB – Kt*/2.3
0
Equation


Du :cumulative amount of the drug K: total elimination rate constant
excreted unchanged in the urine ke: the renal excretion rate constant
0
Du: cumulative amount of the drug DB : initial amount of drug in the body
excreted unchanged in the urine after Du:amount of drug excreted
time t unchanged in urine after time t
t: time interval for collection of urine
Assumptions
sample
t*: midpoint of collection period

t* = (t1 +t2) / 2

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