Pharmacokinetics in dosage form design MCQs With Answer

Introduction: Pharmacokinetics in dosage form design MCQs With Answer is a targeted question set for M.Pharm students focusing on how pharmacokinetic principles guide rational dosage form design. These MCQs cover absorption, distribution, metabolism, elimination, and key concepts such as bioavailability, clearance, volume of distribution, release kinetics, IVIVC, and therapeutic drug monitoring. Each question links mechanistic understanding to practical formulation and clinical considerations—helpful for exam prep and classroom revision. Expect scenario-based items that require application of equations, interpretation of profiles, and design choices for immediate, controlled, or targeted delivery systems.

Q1. Which parameter most directly determines the fraction of an orally administered drug reaching systemic circulation unchanged?

• Volume of distribution
• Hepatic extraction ratio
• Bioavailability (F)
• Clearance

Correct Answer: Bioavailability (F)

Q2. A drug exhibits flip-flop kinetics in a sustained-release oral formulation. Which statement best describes flip-flop kinetics?

• Elimination rate constant is much slower than absorption rate constant
• Absorption rate constant is slower than elimination rate constant
• Absorption and elimination rates are equal
• Drug shows zero-order elimination only

Correct Answer: Absorption rate constant is slower than elimination rate constant

Q3. When designing an enteric-coated tablet for an acid-labile drug, which pharmacokinetic consideration is most critical?

• Drug’s renal clearance
• Site-specific absorption pH and stability in stomach
• Drug’s protein binding in plasma
• Volume of distribution

Correct Answer: Site-specific absorption pH and stability in stomach

Q4. Which of the following best defines volume of distribution (Vd)?

• The volume of fluid from which the drug is completely removed per unit time
• A proportionality constant relating amount of drug in the body to plasma concentration
• The fraction of drug bound to plasma proteins
• The clearance adjusted for body weight

Correct Answer: A proportionality constant relating amount of drug in the body to plasma concentration

Q5. In designing a controlled-release formulation to maintain steady plasma concentrations, which PK parameter is most important for determining dosing interval?

• Volume of distribution
• Half-life (t1/2)
• Bioavailability
• Apparent clearance

Correct Answer: Half-life (t1/2)

Q6. A drug follows Michaelis–Menten (nonlinear) elimination. Which dosing consequence is expected if dose is increased above Km region?

• Clearance remains constant and proportionality of dose to AUC is maintained
• AUC increases disproportionately due to saturation of elimination pathways
• Volume of distribution increases linearly with dose
• Bioavailability decreases with increase in dose

Correct Answer: AUC increases disproportionately due to saturation of elimination pathways

Q7. For a weakly basic drug with pKa 8.5 administered orally, where is absorption most favored according to pH-partition theory?

• Stomach (pH ~1-3)
• Duodenum (pH ~4-6)
• Small intestine (pH ~6-7.5)
• Colon (pH ~7-8)

Correct Answer: Small intestine (pH ~6-7.5)

Q8. In an immediate release tablet, which formulation factor most directly affects the drug’s absorption rate?

• Drug’s systemic clearance
• Dissolution rate and particle size
• Hepatic extraction ratio
• Plasma protein binding

Correct Answer: Dissolution rate and particle size

Q9. Which equation correctly describes absolute oral bioavailability (F)?

• F = (AUCpo / Dosepo) / (AUCiv / Doseiv)
• F = Clearance × Volume of distribution
• F = Fraction unbound in plasma / Fraction unbound in tissue
• F = 0.693 / t1/2

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

Q10. Which clearance term describes the theoretical volume of plasma completely cleared of drug by the kidney per unit time?

• Hepatic clearance
• Total body clearance
• Renal clearance
• Biliary clearance

Correct Answer: Renal clearance

Q11. A formulation scientist wants IVIVC for a modified-release oral product. Which in vitro parameter is most predictive for in vivo absorption?

• Particle morphology observed by SEM
• Dissolution rate under biorelevant media and agitation
• Tablet hardness alone
• Color and odor of the tablet

Correct Answer: Dissolution rate under biorelevant media and agitation

Q12. High plasma protein binding of a drug primarily affects which pharmacokinetic property?

• Only renal clearance because bound drug is excreted faster
• Apparent volume of distribution and free fraction available for elimination
• Oral dissolution rate in the GI tract
• Intrinsic hepatic clearance independent of free concentration

Correct Answer: Apparent volume of distribution and free fraction available for elimination

Q13. Which strategy increases bioavailability of a low-permeability, low-solubility drug intended for oral delivery?

• Decrease particle surface area
• Use solubilizing excipients or solid dispersion to enhance dissolution and permeability enhancers
• Increase binding to plasma proteins
• Reduce contact time in the intestinal lumen

Correct Answer: Use solubilizing excipients or solid dispersion to enhance dissolution and permeability enhancers

Q14. For a drug with high hepatic extraction ratio (E close to 1), oral bioavailability is most affected by which of the following?

• Renal clearance variations
• First-pass hepatic metabolism and hepatic blood flow
• Plasma protein binding changes only
• Gastric emptying time exclusively

Correct Answer: First-pass hepatic metabolism and hepatic blood flow

Q15. Therapeutic drug monitoring (TDM) is most useful for drugs with which characteristics?

• Narrow therapeutic index, high interpatient PK variability, and a clear concentration-response relationship
• Wide therapeutic index and predictable PK across patients
• Only topical drugs with no systemic exposure
• Drugs eliminated exclusively by zero-order renal excretion

Correct Answer: Narrow therapeutic index, high interpatient PK variability, and a clear concentration-response relationship

Q16. Loading dose is calculated to rapidly achieve target concentration. Which formula is correct for loading dose (LD)?

• LD = CL × Css × dosing interval
• LD = Vd × Css / Bioavailability (F)
• LD = 0.693 × Vd / CL
• LD = AUC × CL

Correct Answer: LD = Vd × Css / Bioavailability (F)

Q17. Which kinetic process is most relevant when designing a transdermal patch for sustained systemic delivery?

• Gastrointestinal first-pass metabolism
• Skin permeation (partitioning and diffusion) and steady-state flux control
• Renal tubular secretion
• Pulmonary absorption dynamics

Correct Answer: Skin permeation (partitioning and diffusion) and steady-state flux control

Q18. In a two-compartment model, which kinetic event occurs immediately after an intravenous bolus dose?

• Only elimination from the peripheral compartment
• Rapid distribution phase between central and peripheral compartments followed by a slower elimination phase
• Zero-order absorption from the GI tract
• Immediate steady-state concentration achieved

Correct Answer: Rapid distribution phase between central and peripheral compartments followed by a slower elimination phase

Q19. Which formulation approach can reduce peak–trough fluctuations for a drug requiring stable plasma levels?

• Immediate release tablets administered once daily
• Controlled-release matrix or osmotic pump delivery
• Use of fast-disintegrating sublingual tablets
• Increasing the administered dose without changing formulation

Correct Answer: Controlled-release matrix or osmotic pump delivery

Q20. Which statement best describes the purpose of prodrug design from a pharmacokinetic perspective?

• To increase renal clearance of the active drug
• To improve absorption, distribution, or stability and thereby enhance bioavailability or target delivery
• To permanently bind the drug to plasma proteins
• To eliminate the need for metabolism before excretion

Correct Answer: To improve absorption, distribution, or stability and thereby enhance bioavailability or target delivery

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