Pharmacokinetic models MCQs With Answer

Pharmacokinetic models MCQs With Answer is designed specifically for M.Pharm students preparing for advanced exams and practical applications in clinical pharmacokinetics. This set focuses on compartmental and non-compartmental models, parameter estimation, nonlinear kinetics, and dosing concepts such as loading dose, maintenance infusion, and steady state. Questions emphasize interpretation of model parameters (Vd, CL, t1/2, MRT), methods like method of residuals and AUC/AUMC calculations, and practical issues including flip‑flop kinetics, allometric scaling, and population modeling tools. Each MCQ targets conceptual depth and problem-solving skills to help you master pharmacokinetic modeling for research, therapeutic drug monitoring, and rational dose design.

Q1. Which assumption defines a one-compartment pharmacokinetic model after an IV bolus dose?

• The body behaves as a single kinetically homogeneous compartment with instantaneous distribution
• The drug distributes to a central and multiple peripheral compartments with slow exchange
• Elimination occurs only from a peripheral compartment
• Absorption is the rate‑limiting step

Correct Answer: The body behaves as a single kinetically homogeneous compartment with instantaneous distribution

Q2. In a two‑compartment IV bolus model, what do the macro‑rate constants alpha (α) and beta (β) represent?

• α is the terminal elimination rate constant and β is the distribution rate constant
• α is the rapid distribution phase rate constant and β is the slower terminal elimination rate constant
• Both α and β represent absorption rate constants for two absorption sites
• α represents absorption and β represents bioavailability

Correct Answer: α is the rapid distribution phase rate constant and β is the slower terminal elimination rate constant

Q3. Which volume best describes the apparent volume of distribution at steady state (Vdss)?

• The volume calculated from initial concentration immediately after IV bolus (Vdinitial)
• The volume that accounts for distribution into peripheral compartments at equilibrium between central and peripheral compartments
• The plasma volume only
• The urine volume required to excrete the dose

Correct Answer: The volume that accounts for distribution into peripheral compartments at equilibrium between central and peripheral compartments

Q4. Clearance (CL) is best defined as which of the following?

• The fraction of drug eliminated per unit time
• The volume of plasma from which drug is completely removed per unit time
• The total amount of drug eliminated per unit time
• The product of Vd and elimination rate constant

Correct Answer: The volume of plasma from which drug is completely removed per unit time

Q5. For a one‑compartment IV bolus model with first‑order elimination, which equation gives the elimination half‑life?

• t1/2 = 0.693 / CL
• t1/2 = (0.693 × Vd) / CL
• t1/2 = CL / (0.693 × Vd)
• t1/2 = Vd / CL × 2

Correct Answer: t1/2 = (0.693 × Vd) / CL

Q6. How is total body clearance estimated from an IV bolus dose using AUC?

• CL = Dose × AUC
• CL = Dose / AUC
• CL = AUC / Dose
• CL = Dose × AUMC

Correct Answer: CL = Dose / AUC

Q7. Which technique is commonly used to separate distribution and elimination phases and estimate micro‑constants in a biexponential plasma decay?

• Method of residuals (feathering)
• Nonlinear mixed effects modelling only
• Noncompartmental trapezoidal approximation
• Direct measurement of tissue concentrations

Correct Answer: Method of residuals (feathering)

Q8. Which statement correctly describes nonlinear (Michaelis‑Menten) pharmacokinetics?

• Clearance is constant and independent of concentration
• Elimination follows first‑order kinetics at all concentrations
• At high concentrations, elimination becomes capacity‑limited and clearance decreases with increasing dose
• Bioavailability increases linearly with dose

Correct Answer: At high concentrations, elimination becomes capacity‑limited and clearance decreases with increasing dose

Q9. Flip‑flop kinetics is observed when which condition holds for an extravascular administration?

• Absorption is much faster than elimination so Ka >> Ke
• Absorption is much slower than elimination so Ka << Ke
• Bioavailability is 100%
• Distribution is instantaneous

Correct Answer: Absorption is much slower than elimination so Ka << Ke

Q10. Approximately how long does it take to reach >95% of steady‑state concentration during repeated dosing or constant infusion for first‑order kinetics?

• One half‑life
• Two to three half‑lives
• Four to five half‑lives
• Ten to twelve half‑lives

Correct Answer: Four to five half‑lives

Q11. What is the formula for calculating a loading dose (LD) to rapidly achieve a target plasma concentration (Css_target) for an IV administration?

• LD = Css_target × CL
• LD = Css_target × Vd
• LD = Css_target / Vd
• LD = CL / Css_target

Correct Answer: LD = Css_target × Vd

Q12. For a continuous IV infusion at steady state, the maintenance infusion rate required to maintain a target plasma concentration is given by which expression?

• Rate_in = Vd × Css × Ke
• Rate_in = CL × Css
• Rate_in = Dose / AUC
• Rate_in = Css / CL

Correct Answer: Rate_in = CL × Css

Q13. Absolute bioavailability (F) for an oral dose is calculated by which equation using AUC values?

• F = (AUC_iv / AUC_po) × (Dose_po / Dose_iv)
• F = (AUC_po / AUC_iv) × (Dose_iv / Dose_po)
• F = (AUC_po × Dose_po) / (AUC_iv × Dose_iv)
• F = (AUC_iv / Dose_iv) × (AUC_po / Dose_po)

Correct Answer: F = (AUC_po / AUC_iv) × (Dose_iv / Dose_po)

Q14. Mean residence time (MRT) can be estimated from concentration–time data by which relationship?

• MRT = AUC / AUMC
• MRT = AUMC / AUC
• MRT = Vd / CL
• MRT = 0.693 / Ke

Correct Answer: MRT = AUMC / AUC

Q15. Which statement about noncompartmental analysis (NCA) is correct?

• NCA requires specification of a compartmental model to estimate clearance
• NCA uses AUC and moments and does not require assuming a specific compartmental model
• NCA can only be used for drugs with nonlinear kinetics
• NCA provides individual micro‑constants directly from biexponential fits

Correct Answer: NCA uses AUC and moments and does not require assuming a specific compartmental model

Q16. In population pharmacokinetic modeling, which software is specifically known for nonlinear mixed‑effects (population) analysis widely used in M.Pharm research?

• WinNonlin
• NONMEM
• GraphPad Prism
• Excel Solver

Correct Answer: NONMEM

Q17. Which parameter is directly obtained from the terminal slope (lambda_z) of the log plasma concentration vs time plot?

• Clearance (CL)
• Terminal half‑life (t1/2) as t1/2 = 0.693 / lambda_z
• Volume of distribution at steady state (Vdss)
• Absolute bioavailability (F)

Correct Answer: Terminal half‑life (t1/2) as t1/2 = 0.693 / lambda_z

Q18. Which model structure best describes a mammillary model used in compartmental PK?

• All compartments are connected in series with elimination from the last compartment
• One central compartment connected to one or more peripheral compartments with elimination from the central compartment
• Multiple central compartments with independent elimination from each
• Only peripheral compartments with elimination but no central compartment

Correct Answer: One central compartment connected to one or more peripheral compartments with elimination from the central compartment

Q19. Which criterion helps choose between competing pharmacokinetic models by penalizing model complexity while rewarding goodness of fit?

• Least squares residual sum
• Akaike Information Criterion (AIC)
• Area under the curve (AUC)
• Maximum concentration (Cmax)

Correct Answer: Akaike Information Criterion (AIC)

Q20. Allometric scaling of clearance across species or body sizes commonly uses which exponent on body weight for physiological scaling?

• Exponent of 1.5
• Exponent of 1.0
• Exponent of 0.75
• Exponent of 0.25

Correct Answer: Exponent of 0.75

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