Principle of bioavailability studies MCQs With Answer

Principle of bioavailability studies MCQs With Answer

Introduction: This quiz collection focuses on the fundamental principles of bioavailability studies tailored for M.Pharm students preparing for Modern Bio-Analytical Techniques (MPA 202T). It covers theoretical concepts and practical considerations such as definitions of bioavailability, pharmacokinetic parameters (AUC, Cmax, Tmax), study designs, sampling and washout, bioanalytical method considerations, statistical evaluation for bioequivalence, IVIVC and deconvolution, and regulatory acceptance criteria. Each question emphasizes clinical and analytical implications, helping students deepen understanding for exams and practical research. Answers are provided for quick self-assessment and focused revision of core topics used in industry and regulatory submissions.

Q1. What is the definition of bioavailability?

• Fraction of administered dose that reaches the systemic circulation in unchanged form
• Rate at which a drug is metabolized in the liver
• Fraction of drug that reaches the target tissue regardless of chemical form
• Volume of distribution normalized to body weight

Correct Answer: Fraction of administered dose that reaches the systemic circulation in unchanged form

Q2. How is absolute bioavailability determined?

• By comparing an oral formulation to an intravenous dose of the same drug
• By comparing two oral formulations of the same drug
• By measuring only the Cmax of the formulation
• By calculating only the Tmax of the formulation

Correct Answer: By comparing an oral formulation to an intravenous dose of the same drug

Q3. Which pharmacokinetic metric best represents the extent of absorption?

• Area under the plasma concentration–time curve (AUC)
• Time to reach maximum concentration (Tmax)
• Apparent volume of distribution (Vd)
• Elimination rate constant (ke)

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

Q4. Which parameter is most commonly used to describe the rate of absorption?

• Time to reach maximum plasma concentration (Tmax)
• Area under the curve (AUC)
• Apparent clearance (CL/F)
• Apparent volume of distribution (Vd/F)

Correct Answer: Time to reach maximum plasma concentration (Tmax)

Q5. What is the definition of Tmax?

• Time after dosing at which the maximum plasma concentration is observed
• Time required to eliminate 50% of the drug
• Time taken for complete absorption of the drug
• Time taken for plasma concentration to fall below LLOQ

Correct Answer: Time after dosing at which the maximum plasma concentration is observed

Q6. Which numerical method is typically used to calculate AUC in non-compartmental analysis?

• Trapezoidal rule (linear trapezoidal with log-linear terminal extrapolation)
• Euler’s method
• Runge-Kutta numerical integration
• Newton-Raphson iterative integration

Correct Answer: Trapezoidal rule (linear trapezoidal with log-linear terminal extrapolation)

Q7. What is the commonly accepted bioequivalence range for the ratio of test to reference geometric means for AUC and Cmax?

• 80%–125% (90% confidence interval)
• 70%–130% (95% confidence interval)
• 90%–110% (90% confidence interval)
• 75%–135% (99% confidence interval)

Correct Answer: 80%–125% (90% confidence interval)

Q8. Which study design is standard for single-dose bioequivalence studies in healthy volunteers?

• Two-way crossover design (two-period, two-sequence)
• Single-arm open-label design
• Parallel group design with unequal allocation
• Multiple ascending dose design

Correct Answer: Two-way crossover design (two-period, two-sequence)

Q9. What is the recommended minimum washout period between treatments in a crossover bioavailability study?

• At least five half-lives of the drug
• One half-life of the drug
• 24 hours regardless of half-life
• At least ten times the dosing interval

Correct Answer: At least five half-lives of the drug

Q10. What does LLOQ stand for in bioanalytical assays?

• Lower limit of quantification: lowest concentration measurable with acceptable accuracy and precision
• Lowest limit of qualification: lowest validated calibration point
• Limit of linear quantitation: point where assay stops being linear
• Lower limit of qualification: minimal sample volume for the assay

Correct Answer: Lower limit of quantification: lowest concentration measurable with acceptable accuracy and precision

Q11. Which validation parameter assesses the reproducibility of repeated measurements under the same conditions?

• Precision
• Accuracy
• Selectivity
• Stability

Correct Answer: Precision

Q12. What is the role of deconvolution in bioavailability analysis?

• To estimate the in vivo input (absorption) rate profile by separating absorption from disposition using reference data
• To simulate drug-drug interactions using in vitro data alone
• To calculate elimination half-life from steady-state concentrations
• To normalize concentrations across different analytical assays

Correct Answer: To estimate the in vivo input (absorption) rate profile by separating absorption from disposition using reference data

Q13. When is partial AUC particularly useful in bioavailability or bioequivalence assessment?

• When early exposure within a specified time window is clinically relevant
• When only the terminal phase is of interest
• When the drug has irreversible binding and no measurable plasma levels
• When clearance is extremely high (>1 L/min)

Correct Answer: When early exposure within a specified time window is clinically relevant

Q14. For a prodrug that is rapidly converted to an active metabolite, which analyte is most relevant for bioavailability assessment?

• The active metabolite (active moiety) concentrations
• The unchanged prodrug only
• Urinary excretion of the prodrug only
• Total radioactivity without speciation

Correct Answer: The active metabolite (active moiety) concentrations

Q15. What statistical approach is typically used to compare primary PK parameters in bioequivalence studies?

• ANOVA on log-transformed AUC and Cmax with calculation of 90% confidence intervals for the ratio
• Untransformed t-test for mean differences with 95% confidence intervals
• Mann-Whitney U test on raw data
• Chi-square test comparing categorical concentration bins

Correct Answer: ANOVA on log-transformed AUC and Cmax with calculation of 90% confidence intervals for the ratio

Q16. When is relative bioavailability assessed instead of absolute bioavailability?

• When an intravenous formulation is not available or when IV administration is unethical
• When absolute bioavailability exceeds 100%
• Only for topical formulations with local action
• When drug is administered by inhalation exclusively

Correct Answer: When an intravenous formulation is not available or when IV administration is unethical

Q17. What is a major limitation of microdosing studies for predicting therapeutic-dose bioavailability?

• Microdoses may not predict full-dose pharmacokinetics if non-linear absorption, distribution, metabolism, or excretion exist
• They always overestimate first-pass metabolism
• They require substantially larger sample volumes than therapeutic studies
• They cannot be analyzed by LC-MS techniques

Correct Answer: Microdoses may not predict full-dose pharmacokinetics if non-linear absorption, distribution, metabolism, or excretion exist

Q18. Which description best matches a Level A in vitro–in vivo correlation (IVIVC)?

• A point-to-point relationship between in vitro dissolution and the in vivo absorption rate or fraction absorbed
• A rank order relationship across different formulations only
• A single-point correlation using Cmax only
• An in vitro potency assay correlated to clinical efficacy

Correct Answer: A point-to-point relationship between in vitro dissolution and the in vivo absorption rate or fraction absorbed

Q19. For drugs exhibiting linear pharmacokinetics, which parameter remains constant across therapeutic doses?

• Clearance (CL) remains approximately constant
• Maximum concentration (Cmax) remains constant regardless of dose
• Area under the curve (AUC) is independent of dose
• Half-life is directly proportional to dose

Correct Answer: Clearance (CL) remains approximately constant

Q20. Approximately how many half-lives are required to reach steady state after repeated dosing?

• About 4–5 half-lives
• One half-life
• About 10–12 half-lives
• Steady state is immediate after the first dose

Correct Answer: About 4–5 half-lives

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