T11: Mixed problems from T7 - T11.
50. Pharmacokinetics 50.1) PK Basic parameters 50.1.2) Clearance
50.1.2.1) Clearance basic concepts Normal 1
Total tried: Correct: Wrong:
The plasma half life `t_{1/2}` of a drug is 3.98 h. If its volume of distribution in a patient is 33.6 L, then determine the clearance of the drug.
Click on the button below to see the answer and explanations
lb equals 5.846 L/h kg
-
We know that, clearance (Cl) is the product of elimination rate constant (K) and volume of distribution (V).
` Cl = K × V `.
Also, the relationship between K and plasma half life, `t_{½}` is:
`t_{½}=0.693/K ⇒ K=0.693/(3.98 \quad h)=0.174 \quad h^{-1}`
Plugging the values given in this question we get:
` Cl = 0.174 \quad h^{-1} × 33.6 \quad L = 5.85 \quad L/h ` Ans