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

5. Ampicillin is an antibiotic that is eliminated from the body by first-order process.

Calculate ampicillin first-order elimination rate constant if the amount of ampicillin

remaining in the body 6 h after administration of a single IV dose of 500 mg is 20.8
−1
mg. (ANSWER: K= 0.53 h )

-1
6. An antibiotic has a volume of distribution of 10 L and a k of 0.2 h . A steady-state
plasma concentration of 10 μg/mL is desired. What is the infusion rate needed to

maintain this concentration? (ANSWER: R= 20 mg/h)

7. A patient was given an antibiotic (t ½ = 6 hrs) by constant IV infusion at a rate of 2

mg/h. At the end of 2 days, the serum drug concentration was 10 mg/L. Calculate the

total body clearance (Cl) for this antibiotic? (ANSWER: Cl= 200 mL/h)

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