Biopharmaceutic Factors Affecting Bioavailability MCQs With Answer

Biopharmaceutic Factors Affecting Bioavailability MCQs With Answer

by

Introduction: This collection of MCQs on Biopharmaceutic Factors Affecting Bioavailability is designed for M.Pharm students preparing for MIP 201T – Advanced Biopharmaceutics & Pharmacokinetics. The questions emphasize mechanistic understanding of how drug properties, formulation variables, physiological conditions and administration routes influence systemic availability. Topics include dissolution, permeability, pKa, solubility, particle size, salt forms, excipients, food and disease effects, first‑pass metabolism, transporters, and advanced concepts such as lymphatic uptake and enterohepatic recycling. Each question tests applied knowledge essential for formulation development, bioequivalence interpretation and clinical pharmacokinetics. Use these MCQs to deepen conceptual clarity and exam readiness.

Q1. Which of the following physicochemical properties most directly governs the rate of passive transcellular absorption across intestinal epithelium?

  • Drug molecular weight only
  • pKa alone
  • Partition coefficient (log P) and permeability
  • Crystal habit

Correct Answer: Partition coefficient (log P) and permeability

Q2. A weakly basic drug with pKa 8.5 is given orally. Which GI condition will most favor its ionization and reduce its intestinal permeability?

  • Alkaline intestinal pH such as postprandial small intestine
  • Normal gastric acidic pH
  • Elevated gastric pH due to proton pump inhibitor
  • Neutral pH in distal colon

Correct Answer: Elevated gastric pH due to proton pump inhibitor

Q3. Which formulation strategy is most appropriate to increase the dissolution rate of a poorly water‑soluble BCS class II drug?

  • Increase particle size
  • Use amorphous solid dispersion or micronization
  • Add a high melting point crystalline form
  • Administer as an enteric coated tablet

Correct Answer: Use amorphous solid dispersion or micronization

Q4. Which excipient is commonly used to enhance solubility and can significantly increase oral bioavailability of poorly soluble drugs?

  • Microcrystalline cellulose
  • Polysorbate (solubilizing surfactant)
  • Magnesium stearate (lubricant)
  • Silicon dioxide (glidant)

Correct Answer: Polysorbate (solubilizing surfactant)

Q5. First‑pass hepatic metabolism primarily affects which pharmacokinetic parameter related to oral dosing?

  • Volume of distribution
  • Absolute oral bioavailability
  • Renal clearance
  • Protein binding in plasma

Correct Answer: Absolute oral bioavailability

Q6. How does increasing drug lipophilicity (higher log P) generally influence oral absorption and bioavailability?

  • Always decreases absorption due to poor dissolution
  • Improves membrane permeation but may reduce solubility and increase first‑pass metabolism
  • Has no effect on absorption
  • Always increases renal elimination

Correct Answer: Improves membrane permeation but may reduce solubility and increase first‑pass metabolism

Q7. Which physiological factor most directly determines the residence time of an immediate‑release oral dosage form in the stomach?

  • Gastric emptying rate
  • Colonic transit time
  • Biliary secretion rate
  • Renal blood flow

Correct Answer: Gastric emptying rate

Q8. P‑glycoprotein (P‑gp) efflux transporters in enterocytes impact bioavailability by which mechanism?

  • Enhancing passive diffusion into blood
  • Pumping drug back into the intestinal lumen, reducing absorption
  • Increasing metabolic stability in enterocytes
  • Facilitating lymphatic uptake

Correct Answer: Pumping drug back into the intestinal lumen, reducing absorption

Q9. Which change in drug formulation would most likely reduce inter‑subject variability in bioavailability caused by food?

  • Formulate as a lipid‑based self‑emulsifying system
  • Use coarse API crystals
  • Design as immediate release powder to be sprinkled
  • Increase tablet hardness without dissolution enhancers

Correct Answer: Formulate as a lipid‑based self‑emulsifying system

Q10. Enterohepatic recirculation can lead to which of the following effects on plasma concentration–time profile?

  • Mono‑exponential decline with no peaks
  • Secondary peaks or prolonged elimination phase
  • Immediate complete elimination
  • Reduced absorption phase only

Correct Answer: Secondary peaks or prolonged elimination phase

Q11. Which property of a drug will most influence its likelihood of significant lymphatic absorption after oral lipid‑based formulation?

  • High water solubility
  • High lipophilicity and triglyceride solubility
  • Extensive renal elimination
  • Strong basicity (high pKa)

Correct Answer: High lipophilicity and triglyceride solubility

Q12. How does particle size reduction of an API typically affect the absorption rate and bioavailability of a poorly soluble drug?

  • Decreases surface area and reduces dissolution
  • Increases surface area, enhancing dissolution rate and often bioavailability
  • Has no impact on dissolution or absorption
  • Always causes precipitation in GI tract and reduces bioavailability

Correct Answer: Increases surface area, enhancing dissolution rate and often bioavailability

Q13. Which salt form selection principle is most relevant to improve oral bioavailability of an ionizable drug?

  • Choose the least soluble salt to prolong GI residence
  • Select a salt that provides higher aqueous solubility at physiological pH
  • Always use the hydrochloride salt regardless of pKa
  • Prefer crystalline free base to maximize stability

Correct Answer: Select a salt that provides higher aqueous solubility at physiological pH

Q14. Which clinical condition would most likely decrease oral bioavailability of a drug that requires bile salt micelles for solubilization?

  • Chronic pancreatitis with bile salt deficiency
  • Hyperthyroidism
  • Increased gastric acid secretion
  • Enhanced intestinal motility

Correct Answer: Chronic pancreatitis with bile salt deficiency

Q15. The Biopharmaceutics Classification System (BCS) classifies drugs based on solubility and permeability. Which BCS class typically shows dissolution‑limited absorption but good permeability?

  • BCS Class I
  • BCS Class II
  • BCS Class III
  • BCS Class IV

Correct Answer: BCS Class II

Q16. Co‑administration of a strong CYP3A4 inhibitor with an orally administered drug that is a CYP3A4 substrate will most likely cause what effect on bioavailability?

  • Decrease bioavailability due to induction
  • Increase systemic exposure and apparent bioavailability by reducing first‑pass metabolism
  • No change because CYP enzymes do not affect oral drugs
  • Complete loss of absorption

Correct Answer: Increase systemic exposure and apparent bioavailability by reducing first‑pass metabolism

Q17. Which dissolution medium factor is essential to simulate in vitro to predict behavior of weakly acidic drugs in vivo?

  • Osmolality
  • pH gradient between stomach and intestine
  • Color of medium
  • Presence of renal enzymes

Correct Answer: pH gradient between stomach and intestine

Q18. Which formulation approach can mask pH‑dependent solubility and reduce variability caused by gastric pH changes?

  • Designing a pH‑dependent enteric coated immediate release tablet
  • Formulating as a pH‑independent amorphous solubility enhancer (e.g., amorphous solid dispersion)
  • Using large crystalline API particles
  • Avoiding any solubilizers or surfactants

Correct Answer: Formulating as a pH‑independent amorphous solubility enhancer (e.g., amorphous solid dispersion)

Q19. Which measurement is used to calculate absolute bioavailability of an oral drug?

  • Comparison of area under curve (AUC) after oral dose to AUC after intravenous dose corrected for dose
  • Peak plasma concentration (Cmax) only
  • Urinary excretion after oral dosing only
  • Volume of distribution after oral dosing

Correct Answer: Comparison of area under curve (AUC) after oral dose to AUC after intravenous dose corrected for dose

Q20. How can high gastrointestinal motility (e.g., diarrhea) influence oral drug bioavailability?

  • Prolongs GI residence time and increases absorption of poorly soluble drugs
  • Reduces contact time for dissolution and absorption, potentially decreasing bioavailability, especially for low permeability or poorly soluble drugs
  • Has no effect on orally administered drugs
  • Enhances first‑pass hepatic metabolism only

Correct Answer: Reduces contact time for dissolution and absorption, potentially decreasing bioavailability, especially for low permeability or poorly soluble drugs

Leave a Comment