Pharmacy Drug Delivery Systems 2 — Questions and Answers
Question 1: Which parameter is MOST critical when designing a transdermal patch for a drug with high molecular weight?
- Skin permeation enhancement (Correct answer)
- Tablet hardness
- Capsule shell solubility
- Viscosity of oral solution
Correct answer: Skin permeation enhancement
High molecular weight drugs penetrate skin poorly, so permeation enhancers are critical for effective transdermal delivery.
Question 2: A drug formulated as a liposome is BEST described as:
- A solid lipid nanoparticle
- A phospholipid bilayer vesicle encapsulating drug (Correct answer)
- A microemulsion of oil and water
- A polymer-drug conjugate
Correct answer: A phospholipid bilayer vesicle encapsulating drug
Liposomes are closed phospholipid bilayer vesicles that can encapsulate both hydrophilic and hydrophobic drugs.
Question 3: Which route of administration completely bypasses first-pass metabolism?
- Oral
- Rectal (partial)
- Intravenous (Correct answer)
- Sublingual
Correct answer: Intravenous
Intravenous administration delivers drug directly to systemic circulation, entirely bypassing hepatic first-pass metabolism.
Question 4: An osmotic pump tablet (OROS) releases drug primarily by:
- pH-triggered dissolution
- Osmotic pressure driving drug through a laser-drilled orifice (Correct answer)
- Enzymatic degradation of the coating
- Erosion of the wax matrix
Correct answer: Osmotic pressure driving drug through a laser-drilled orifice
OROS tablets use osmotic pressure built up by water influx to push drug solution through a precisely drilled delivery orifice.
Question 5: Which excipient class is commonly used in hot-melt extrusion to improve drug solubility?
- Enteric polymers like HPMC-AS (Correct answer)
- Magnesium stearate
- Microcrystalline cellulose
- Talc
Correct answer: Enteric polymers like HPMC-AS
HPMC-AS and similar polymers form solid dispersions via hot-melt extrusion, improving the solubility of poorly water-soluble drugs.
Question 6: Mucoadhesive drug delivery systems are designed primarily to:
- Increase first-pass metabolism
- Prolong contact time with mucosal membranes (Correct answer)
- Accelerate gastric emptying
- Reduce drug particle size
Correct answer: Prolong contact time with mucosal membranes
Mucoadhesive systems use polymers that adhere to mucosal surfaces, extending residence time and improving drug absorption.
Question 7: A nanoparticle drug carrier with a size of 10–200 nm is MOST likely to accumulate in tumor tissue via:
- Active receptor targeting only
- Enhanced permeability and retention (EPR) effect (Correct answer)
- Ion-pair transport
- Carrier-mediated endocytosis exclusively
Correct answer: Enhanced permeability and retention (EPR) effect
The EPR effect allows nanoparticles to passively accumulate in tumors due to leaky vasculature and poor lymphatic drainage.
Pharmacy Drug Delivery Systems 2
Which parameter is MOST critical when designing a transdermal patch for a drug with high molecular weight?