Evaluation of ophthalmic preparations MCQs With Answer

Evaluation of ophthalmic preparations is a crucial subject for B.Pharm students, covering quality control, safety and efficacy of eye drops, ointments, suspensions and gels. Key topics include sterility testing, preservative efficacy (microbial challenge), pH and tonicity adjustment, viscosity/rheology, particle size and zeta potential, endotoxin (LAL) testing, ocular irritation assessment, stability studies and appropriate packaging. Understanding pharmacopeial tests (USP/IP), analytical methods and regulatory requirements ensures safe ocular delivery and optimal bioavailability. Practical laboratory skills such as membrane filtration, microbial assays and physicochemical evaluation are emphasized for sterility assurance and product performance. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which official methods are used for sterility testing of ophthalmic solutions?

• Membrane filtration and direct inoculation
• Plate count and Most Probable Number
• Gram staining and acid-fast staining
• Endotoxin (LAL) and turbidity test

Correct Answer: Membrane filtration and direct inoculation

Q2. Which USP chapter specifically describes sterility tests for pharmaceutical products?

• USP <51>
• USP <61>
• USP <71>
• USP <788>

Correct Answer: USP <71>

Q3. Which test is used to evaluate antimicrobial preservative effectiveness in multi-dose ophthalmic preparations?

• Microbial limit test
• Preservative efficacy test (Antimicrobial effectiveness test)
• Stability indicating assay
• Particulate matter test

Correct Answer: Preservative efficacy test (Antimicrobial effectiveness test)

Q4. The physiological pH of tears, often targeted in ophthalmic formulations, is approximately:

• pH 4.5
• pH 6.0
• pH 7.4
• pH 9.0

Correct Answer: pH 7.4

Q5. An isotonic ophthalmic solution is typically equivalent to which concentration of sodium chloride?

• 0.45% NaCl
• 0.9% NaCl
• 2.0% NaCl
• 5.0% NaCl

Correct Answer: 0.9% NaCl

Q6. Which test method is commonly used to quantify particulate matter in ophthalmic solutions?

• Light obscuration particle count test
• Gram staining
• Viscometry
• pH titration

Correct Answer: Light obscuration particle count test

Q7. Which historical animal test has been widely used to assess ocular irritation of ophthalmic preparations?

• LD50 oral toxicity test
• Draize rabbit eye test
• AMES test
• Fetal teratogenicity test

Correct Answer: Draize rabbit eye test

Q8. Sterility test incubation for pharmaceutical sterility typically involves which pair of temperature ranges?

• 4–8 °C and 15–20 °C
• 20–25 °C and 30–35 °C
• 37–40 °C and 45–50 °C
• 0–5 °C and 10–15 °C

Correct Answer: 20–25 °C and 30–35 °C

Q9. Which preservative is most commonly used in multi-dose ophthalmic solutions?

• Benzalkonium chloride (BAK)
• Sodium chloride
• Glycerin
• Citric acid

Correct Answer: Benzalkonium chloride (BAK)

Q10. Increasing which formulation parameter generally increases ocular residence time of a topical eye drop?

• pH
• Viscosity
• Osmolality
• Surface tension

Correct Answer: Viscosity

Q11. Which technique provides detailed particle size distribution for ophthalmic suspensions?

• Laser diffraction particle size analysis
• Gas chromatography
• UV-visible spectrophotometry
• Flame photometry

Correct Answer: Laser diffraction particle size analysis

Q12. Which assay is used to detect bacterial endotoxins in ophthalmic preparations?

• Gram stain
• Limulus Amebocyte Lysate (LAL) test
• Preservative challenge test
• Thioglycollate growth test

Correct Answer: Limulus Amebocyte Lysate (LAL) test

Q13. The main objective of preservative efficacy testing (PET) is to:

• Measure viscosity changes over time
• Confirm antimicrobial activity of the preservative over a defined period
• Determine pH drift during storage
• Assess osmolarity of the formulation

Correct Answer: Confirm antimicrobial activity of the preservative over a defined period

Q14. For preservative-free ophthalmic solutions intended for frequent dosing, which container type is preferred?

• Multi-dose glass bottle with BAK
• Single-dose (unit-dose) sterile plastic vials
• Opaque metal tins
• Unlabeled open jars

Correct Answer: Single-dose (unit-dose) sterile plastic vials

Q15. Which instrument is typically used to quantify turbidity or clarity of a clear ophthalmic solution?

• Nephelometer or spectrophotometer for turbidity
• Brookfield viscometer
• pH meter
• Hot-stage microscope

Correct Answer: Nephelometer or spectrophotometer for turbidity

Q16. Which parameter is most directly associated with the electrostatic stability of a suspension?

• Viscosity
• Zeta potential
• pH alone
• Surface tension

Correct Answer: Zeta potential

Q17. To minimize ocular irritation and ensure uniform dosing, particle size of ophthalmic suspensions is generally kept below:

• 50 micrometers
• 25 micrometers
• 10 micrometers
• 100 micrometers

Correct Answer: 10 micrometers

Q18. ‘In‑use stability’ testing of an ophthalmic multi-dose product primarily evaluates:

• Sterility and chemical stability during the period after opening and patient use
• Accelerated storage at 60 °C
• Compatibility with oral dosage forms
• Animal toxicity after intravenous administration

Correct Answer: Sterility and chemical stability during the period after opening and patient use

Q19. Which packaging choice best protects a light-sensitive ophthalmic formulation from photodegradation?

• Transparent polypropylene bottle
• Amber glass container
• Thin aluminum foil sachet left unlined
• Clear polyethylene dropper

Correct Answer: Amber glass container

Q20. Which administration route delivers a drug directly into the vitreous cavity, bypassing corneal barriers?

• Topical instillation
• Subconjunctival injection
• Intravitreal injection
• Oral administration

Correct Answer: Intravitreal injection

Q21. The approximate maximum comfortable volume for a single topical drop in the human conjunctival sac is around:

• 1 mL
• 100 µL
• 30 µL
• 500 µL

Correct Answer: 30 µL

Q22. What is a limitation of filter sterilization (0.22 µm) for ophthalmic solutions?

• It removes endotoxins completely
• It removes microorganisms but may not remove bacterial endotoxins
• It increases product viscosity
• It always sterilizes oily suspensions effectively

Correct Answer: It removes microorganisms but may not remove bacterial endotoxins

Q23. The preservative challenge test is also commonly called:

• Antimicrobial preservation test / Microbial challenge test
• Particulate matter assay
• Moisture sorption test
• Endotoxin quantitation

Correct Answer: Antimicrobial preservation test / Microbial challenge test

Q24. Which instrument is standard for measuring viscosity of ophthalmic gels and viscous eye drops?

• pH meter
• Brookfield viscometer
• Mass spectrometer
• Gas chromatograph

Correct Answer: Brookfield viscometer

Q25. Which organisms are typically included in the preservative efficacy test panel?

• Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger
• Escherichia coli only
• Bacillus subtilis and Clostridium sporogenes only
• Lactobacillus acidophilus and Micrococcus luteus only

Correct Answer: Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger

Q26. Which test largely replaced the rabbit pyrogen test for detecting bacterial endotoxin in ophthalmic products?

• Preservative challenge test
• Limulus Amebocyte Lysate (LAL) test
• Gram staining
• Thiocyanate assay

Correct Answer: Limulus Amebocyte Lysate (LAL) test

Q27. Which excipient is known to act as a penetration enhancer for corneal drug absorption?

• Sodium chloride
• Benzalkonium chloride (BAK)
• Purified water
• Glycerin only as a humectant

Correct Answer: Benzalkonium chloride (BAK)

Q28. According to ICH guidelines, an accelerated stability condition commonly used for semi-solid/aqueous formulations is:

• 0 °C ± 2 °C, 20% RH
• 25 °C ± 2 °C, 40% RH
• 40 °C ± 2 °C, 75% RH
• 60 °C ± 5 °C, 90% RH

Correct Answer: 40 °C ± 2 °C, 75% RH

Q29. Chelating agents like EDTA in ophthalmic formulations primarily serve to:

• Increase viscosity dramatically
• Chelate divalent metal ions to improve stability and enhance preservative efficacy
• Act as the primary preservative
• Lower osmolarity to zero

Correct Answer: Chelate divalent metal ions to improve stability and enhance preservative efficacy

Q30. The commonly accepted Sterility Assurance Level (SAL) for terminal sterilization is:

• 10^0
• 10^-3
• 10^-6
• 10^-12

Correct Answer: 10^-6

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