Biopharmaceutics
OU HSC College of Pharmacy
Final Exam 5 May 1999 - Answers - Section 3 Q3
Q 3.3 (10 points) Given that you want to maintain plasma concentrations above 2.5 mg/L for 12 hours, what IV bolus dose would be needed if t1/2 = 3.8 hr and V = 68.6 L? Assume a one compartment linear pharmacokinetic model. What would the expected Cp0 value be if this dose were given.
Cp = Cp0e-kelt = (Dose/V) e-kelt
Note: kel = ln2/3.8 = 0.182 hr-1
2.5 = (Dose/68.6) e-0.182 x 12
Dose = (2.5 x 68.6) / e-2.184 = 1523 mg
Cp0 = 1523 / 68.6 = 22.2 mg/L