B.Pharm. Bachelor of Pharmacy Biopharmaceutics & Pharmacokinetics 3

Question 1

In Michaelis-Menten kinetics, the Km value represents the substrate concentration at which the reaction velocity is:

Accepted Answer

Equal to half of Vmax

Answer

At its maximum (Vmax)

Answer

Zero

Answer

Equal to the clearance rate

Question 2

A loading dose is administered to:

Accepted Answer

Rapidly achieve a therapeutic plasma concentration

Answer

Maintain a steady-state concentration over chronic dosing

Answer

Reduce the rate of drug metabolism

Answer

Test a patient's tolerance to a drug

Question 3

The primary factor limiting drug distribution across the blood-brain barrier (BBB) is the drug's:

Accepted Answer

Ionization state and lipophilicity

Answer

Molecular weight only

Answer

Plasma half-life

Answer

Renal clearance

Question 4

Renal clearance of a drug can be calculated using the formula:

Accepted Answer

Renal clearance = (Urine drug concentration × Urine flow rate) / Plasma drug concentration

Answer

Renal clearance = Dose / AUC

Answer

Renal clearance = Vd × Ke

Answer

Renal clearance = F × Dose / AUC

Question 5

The relationship between half-life (t½) and elimination rate constant (Ke) is expressed as:

Accepted Answer

t½ = 0.693 / Ke

Answer

t½ = Ke / 0.693

Answer

t½ = Ke × Vd

Answer

t½ = Cl / Vd

Question 6

According to FDA bioequivalence criteria, a generic drug is considered bioequivalent to the reference listed drug when its 90% confidence interval for AUC and Cmax ratios falls within:

Accepted Answer

80–125% of the reference product

Answer

70–130% of the reference product

Answer

75–133% of the reference product

Answer

90–110% of the reference product

Question 7

According to the Henderson-Hasselbalch equation, a weakly acidic drug with pKa of 4.0 will be predominantly absorbed in the stomach (pH 1.5) because:

Accepted Answer

The drug exists mostly in the un-ionized lipid-soluble form at gastric pH below its pKa

Answer

Acidic drugs are always absorbed in the stomach regardless of pH

Answer

The large surface area of the stomach favors absorption

Answer

Low pH increases drug solubility and absorption rate