Bioavailability and bioequivalence MCQs With Answer

Introduction: This MCQ set on Bioavailability and Bioequivalence is designed specifically for M.Pharm students studying Advanced Biopharmaceutics & Pharmacokinetics (MPH 202T). It covers core concepts such as absolute and relative bioavailability, pharmacokinetic parameters (AUC, Cmax, Tmax, MRT), study designs for bioequivalence, statistical principles (log-transformation, ANOVA, 90% confidence intervals), BCS biowaivers, food effects, high variability and narrow therapeutic index considerations, IVIVC levels, and formulation-related factors. These questions aim to deepen conceptual understanding and prepare students for exams and practical study planning, with emphasis on interpretation of PK data and regulatory expectations.

Q1. What is the correct formula for calculating absolute bioavailability (F) from plasma AUC values?

• F = (AUCiv / Doseiv) / (AUCpo / Dosepo)
• F = (AUCpo / Dosepo) / (AUCiv / Doseiv)
• F = (Cmax,po / Cmax,iv) × 100
• F = (Tmax,po / Tmax,iv)

Correct Answer: F = (AUCpo / Dosepo) / (AUCiv / Doseiv)

Q2. Relative bioavailability is best described as:

• The fraction of dose reaching systemic circulation after IV administration
• The comparison of bioavailability between two different extravascular formulations or routes
• The comparison of a formulation to an IV reference to get absolute F
• The time to reach maximum concentration (Tmax) between formulations

Correct Answer: The comparison of bioavailability between two different extravascular formulations or routes

Q3. Regulatory bioequivalence acceptance criteria for AUC and Cmax typically require:

• Point estimate within 50–200% without confidence intervals
• 90% confidence interval for the ratio of geometric means to fall within 80–125%
• 95% confidence interval for arithmetic mean ratio to fall within 90–110%
• Non‑parametric comparison of medians with p>0.05

Correct Answer: 90% confidence interval for the ratio of geometric means to fall within 80–125%

Q4. Why are AUC and Cmax usually log-transformed before statistical analysis in BE studies?

• To convert concentration units into time units
• To linearize exponential decay for compartmental fitting
• To normalize skewed distributions and compare geometric means
• To avoid calculating confidence intervals

Correct Answer: To normalize skewed distributions and compare geometric means

Q5. The most common clinical study design for a standard bioequivalence study is:

• Parallel group, multiple ascending dose
• Two-treatment, two-period, two-sequence crossover
• Single-period, single-arm open study
• Four-way full replicate without washout

Correct Answer: Two-treatment, two-period, two-sequence crossover

Q6. A drug is considered highly variable in bioequivalence context if within-subject coefficient of variation (CV) is approximately:

• Less than 10%
• Around 20%
• Greater than 30%
• Exactly 50%

Correct Answer: Greater than 30%

Q7. Which Biopharmaceutics Classification System (BCS) classes are most commonly eligible for a biowaiver for immediate-release solid oral dosage forms?

• Class II (low solubility, high permeability) only
• Class I (high solubility, high permeability) and in some cases Class III (high solubility, low permeability)
• Class IV (low solubility, low permeability) only
• All four classes equally qualify

Correct Answer: Class I (high solubility, high permeability) and in some cases Class III (high solubility, low permeability)

Q8. A standard fed-state bioequivalence study is performed with which type of meal?

• Low-fat snack consumed 1 hour after dosing
• High-fat, high-calorie standardized meal given before dosing
• Random home-cooked meal with no timing control
• Fasting period followed by intravenous infusion

Correct Answer: High-fat, high-calorie standardized meal given before dosing

Q9. Which of the following factors is most likely to reduce oral bioavailability of a drug?

• High aqueous solubility without metabolism
• Extensive first-pass hepatic metabolism and P-glycoprotein efflux
• Immediate-release formulation with rapid dissolution
• Administration as intravenous injection

Correct Answer: Extensive first-pass hepatic metabolism and P-glycoprotein efflux

Q10. When estimating AUC0–∞ using noncompartmental analysis, what maximum percent extrapolation from AUClast to AUC∞ is commonly considered acceptable?

• Greater than 50% is acceptable
• Extrapolation is irrelevant in NCA
• Typically less than 20% of total AUC
• Exact limit is 1% by regulation

Correct Answer: Typically less than 20% of total AUC

Q11. Noncompartmental analysis generally calculates AUC using which method?

• Maximum likelihood estimation
• Trapezoidal rule (linear/log trapezoidal)
• Wiener-Hopf deconvolution
• Monte Carlo simulation

Correct Answer: Trapezoidal rule (linear/log trapezoidal)

Q12. Mean residence time (MRT) is calculated as:

• MRT = AUC / AUMC
• MRT = Cmax / Tmax
• MRT = AUMC / AUC
• MRT = Dose / Clearance

Correct Answer: MRT = AUMC / AUC

Q13. Which statement best defines a Level A in vitro–in vivo correlation (IVIVC)?

• A single-point correlation between dissolution at one time and plasma concentration
• A categorical correlation based on bioequivalence outcomes
• A point-to-point quantitative correlation between in vitro dissolution and in vivo absorption profiles
• An in vitro test that predicts toxicity but not absorption

Correct Answer: A point-to-point quantitative correlation between in vitro dissolution and in vivo absorption profiles

Q14. For narrow therapeutic index (NTI) drugs, regulatory agencies may require tighter bioequivalence limits. Which statement is correct?

• NTI drugs always use 80–125% limits like non-NTI drugs
• NTI drugs may have tighter limits (e.g., ~90–111%) depending on regulator
• NTI drugs are exempt from bioequivalence testing
• NTI drugs use non-inferiority margins instead of equivalence

Correct Answer: NTI drugs may have tighter limits (e.g., ~90–111%) depending on regulator

Q15. Reference-scaling procedures in bioequivalence are used primarily to:

• Allow widening of acceptance limits for highly variable drugs based on within-subject variability of the reference
• Decrease the required sample size for all drugs regardless of variability
• Replace crossover designs with parallel designs automatically
• Eliminate the need for log-transformation of PK metrics

Correct Answer: Allow widening of acceptance limits for highly variable drugs based on within-subject variability of the reference

Q16. Enterohepatic recirculation of a drug typically results in which PK observation?

• A single smooth concentration–time curve with no deviations
• Multiple peaks in the plasma concentration–time profile and prolonged apparent half-life
• Complete absence of measurable plasma concentrations
• Immediate elimination with zero half-life

Correct Answer: Multiple peaks in the plasma concentration–time profile and prolonged apparent half-life

Q17. Which formulation factors can significantly alter oral bioavailability?

• Crystal form (polymorph), salt form, particle size, and excipients affecting dissolution
• Only tablet color and engraving
• Container labeling font size
• Route of administration if given intravenously

Correct Answer: Crystal form (polymorph), salt form, particle size, and excipients affecting dissolution

Q18. Partial AUC metrics are particularly useful in bioequivalence assessment for:

• Intravenous bolus formulations only
• Modified-release products to evaluate early or partial exposure windows
• Determining intravenous clearance directly
• Replacing AUC0–∞ for all immediate-release products

Correct Answer: Modified-release products to evaluate early or partial exposure windows

Q19. Sample size for a bioequivalence study primarily depends on:

• The color of the tablet and the CRO location
• Within-subject variability, expected test/reference ratio, desired power and alpha level
• The study director’s years of experience only
• The AUC units being used (ng·h/mL vs µg·h/L)

Correct Answer: Within-subject variability, expected test/reference ratio, desired power and alpha level

Q20. Which pharmacokinetic parameter is the most direct measure of the extent of systemic drug exposure after a given dose?

• Tmax (time to maximum concentration)
• Cmax (peak plasma concentration)
• AUC (area under the plasma concentration–time curve)
• Half-life (t1/2)

Correct Answer: AUC (area under the plasma concentration–time curve)

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