Advantages and disadvantages of SR and CR systems MCQs With Answer

Advantages and disadvantages of SR and CR systems MCQs With Answer is designed for M. Pharm students studying Drug Delivery Systems (MPH 102T). This quiz emphasizes clinically relevant pharmacokinetic and formulation concepts behind sustained-release (SR) and controlled-release (CR) dosage forms. You will assess how SR/CR technologies improve therapeutic outcomes by smoothing plasma profiles and enhancing adherence, while also exploring their limitations such as dose dumping, food/alcohol effects, absorption-window constraints, and manufacturing complexity. Questions integrate drug and polymer properties, release mechanisms, patient-centric considerations, and regulatory perspectives like IVIVC. Use this set to sharpen decision-making on candidate selection, dosage-form design, risk mitigation, and clinical application of modified-release systems.

Q1. Which key pharmacokinetic advantage do SR/CR systems most directly provide over immediate-release forms?

• Reduced peak–trough fluctuations around the therapeutic window
• Faster onset of action
• Greater Cmax regardless of dose
• Increased dosing frequency for better control

Correct Answer: Reduced peak–trough fluctuations around the therapeutic window

Q2. Which is a principal clinical disadvantage associated with failure of CR dosage forms?

• Guaranteed bioequivalence across populations
• Risk of dose dumping from dosage form failure
• Complete elimination of food effects
• Reduced therapeutic index automatically

Correct Answer: Risk of dose dumping from dosage form failure

Q3. Which drug half-life range is generally most suitable for development into SR/CR oral systems?

• Less than 1 hour
• Between 2 and 6 hours
• Between 12 and 24 hours
• More than 24 hours

Correct Answer: Between 2 and 6 hours

Q4. In which clinical scenario is an SR/CR dosage form most advantageous?

• Acute migraine requiring rapid relief
• Breakthrough cancer pain
• Hypertension maintenance therapy
• Anaphylaxis management

Correct Answer: Hypertension maintenance therapy

Q5. What is the ideal release profile targeted by a well-designed CR dosage form to maintain steady plasma levels?

• Zero-order release kinetics
• First-order release kinetics with high initial burst
• Pulsatile, erratic release
• Immediate bolus followed by no release

Correct Answer: Zero-order release kinetics

Q6. How do SR/CR systems commonly improve medication adherence?

• By increasing dosing frequency to four times daily
• By reducing dosing frequency to once- or twice-daily regimens
• By eliminating adverse effects entirely
• By requiring co-administration with food

Correct Answer: By reducing dosing frequency to once- or twice-daily regimens

Q7. Which drug characteristic often limits the success of oral SR/CR delivery?

• BCS Class I characteristics with high solubility and permeability
• Narrow absorption window confined to the upper small intestine
• Wide therapeutic index
• pH-independent solubility across the GI tract

Correct Answer: Narrow absorption window confined to the upper small intestine

Q8. Which statement best describes a potential food effect on certain CR matrix systems?

• High-fat meals may alter GI motility and hydration, modifying release and absorption
• Food universally eliminates interpatient variability
• Food always increases bioavailability twofold
• Food has no effect on diffusion-controlled systems

Correct Answer: High-fat meals may alter GI motility and hydration, modifying release and absorption

Q9. Compared with matrix systems, which disadvantage is more pronounced in reservoir-type CR systems?

• Higher risk of dose dumping if the rate-controlling membrane ruptures
• Inability to use polymer coatings
• Incompatibility with hydrophobic drugs
• Prohibition of zero-order release by design

Correct Answer: Higher risk of dose dumping if the rate-controlling membrane ruptures

Q10. For drugs with a narrow therapeutic index, what is a key disadvantage of SR/CR formulations?

• Improved titratability and rapid dose adjustment
• Reduced drug–drug interaction potential
• Higher risk of accumulation and toxicity if release is altered
• Guaranteed avoidance of adverse effects

Correct Answer: Higher risk of accumulation and toxicity if release is altered

Q11. How do SR/CR formulations affect time to reach steady state compared with immediate-release when total daily dose and elimination half-life are unchanged?

• Time to steady state is unchanged because it is governed by elimination half-life
• Time to steady state is always much faster
• Time to steady state is always slower regardless of drug properties
• Time to steady state depends only on the in vitro release profile

Correct Answer: Time to steady state is unchanged because it is governed by elimination half-life

Q12. Which development/manufacturing drawback most commonly affects SR/CR products?

• Lower production cost than immediate-release tablets
• Simpler process validation
• Greater formulation complexity requiring specialized equipment and controls
• No need for stability studies

Correct Answer: Greater formulation complexity requiring specialized equipment and controls

Q13. Which stability concern is particularly relevant to hydrophilic matrix SR tablets?

• Polymer hydration sensitivity causing altered gel formation under high humidity
• Complete resistance to moisture uptake
• Guaranteed temperature stability up to 80°C
• Elimination of any need for moisture-protective packaging

Correct Answer: Polymer hydration sensitivity causing altered gel formation under high humidity

Q14. What is a recognized risk when certain CR products are co-administered with alcohol?

• Universal decrease in drug release rate
• Alcohol-induced dose dumping leading to rapid drug release
• Complete prevention of first-pass metabolism
• Guaranteed enhanced bioavailability without risk

Correct Answer: Alcohol-induced dose dumping leading to rapid drug release

Q15. Why is “do not crush or chew” emphasized for many SR/CR tablets and capsules?

• Crushing improves the designed extended-release profile
• Chewing reduces food effects
• Mechanical disruption can release the full dose immediately, increasing toxicity risk
• Crushing enhances stability under humidity

Correct Answer: Mechanical disruption can release the full dose immediately, increasing toxicity risk

Q16. Which advantage is commonly achieved by switching from IR to SR/CR when total exposure (AUC) is similar?

• Lower peak-related adverse effects with comparable therapeutic coverage
• Shorter time to maximum concentration
• Higher frequency of dosing to ensure efficacy
• Elimination of interindividual variability

Correct Answer: Lower peak-related adverse effects with comparable therapeutic coverage

Q17. Which is a potential disadvantage of SR formulations for drugs causing local gastric irritation (e.g., some NSAIDs)?

• Reduced mucosal contact time
• Prolonged gastric residence may worsen local irritation
• Guaranteed protection via diffusion control
• Immediate enteric protection irrespective of coating

Correct Answer: Prolonged gastric residence may worsen local irritation

Q18. Which patient-related factor can increase inter- and intra-subject variability with SR/CR oral forms?

• Uniform GI transit time across all patients
• Constancy of pH and motility regardless of diet
• Variations in GI transit, pH, and motility affecting release and absorption
• Absence of any effect from concomitant medications

Correct Answer: Variations in GI transit, pH, and motility affecting release and absorption

Q19. From a regulatory and development standpoint, which is a potential advantage of establishing a Level A IVIVC for a CR product?

• Eliminates need for GMP compliance
• Allows biowaivers for certain post-approval changes by predicting in vivo from in vitro
• Removes requirement for any clinical studies
• Guarantees zero variability in patients

Correct Answer: Allows biowaivers for certain post-approval changes by predicting in vivo from in vitro

Q20. Why are SR/CR dosage forms generally unsuitable for “as-needed” therapy requiring rapid onset?

• They are designed for delayed and sustained release rather than immediate peak concentrations
• They increase peak concentration instantly
• They are unaffected by physiological conditions
• They always provide pulsatile release

Correct Answer: They are designed for delayed and sustained release rather than immediate peak concentrations

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