Top Interview Questions for Experienced Candidates in Formulation R&D (Oral Solid Dosage)

1. Can you explain the pre-formulation studies conducted before developing an OSD?

Answer:
Pre-formulation studies involve evaluating the physicochemical properties of a drug substance, such as solubility, particle size, polymorphism, flow properties, and stability. These studies help in selecting the right excipients and optimizing the formulation.

2. How do you determine the choice of excipients in OSD formulations?

Answer:
The choice of excipients depends on the drug’s properties and the formulation’s requirements. For example:

• Binders for tablet integrity.
• Disintegrants to ensure rapid breakdown.
• Lubricants to improve manufacturing.
• Solubilizers for poorly soluble drugs.

3. What techniques do you use to enhance the solubility of poorly soluble drugs?

Answer:
Common techniques include:

• Solid dispersion
• Nano-milling
• Use of surfactants or co-solvents
• Complexation with cyclodextrins
• Lipid-based delivery systems.

4. What challenges have you faced during scale-up from R&D to commercial production, and how did you address them?

Answer:
Challenges include:

• Maintaining blend uniformity.
• Equipment differences between pilot and commercial scales.
• Variations in tablet compression force.
  I addressed these by optimizing process parameters, conducting risk assessments, and using QbD (Quality by Design) approaches to identify critical process parameters.

5. Can you explain the concept of bioequivalence and its significance in formulation development?

Answer:
Bioequivalence ensures that the generic formulation has the same bioavailability as the reference product. It is crucial to confirm therapeutic equivalence and regulatory approval.

6. What is the importance of QbD (Quality by Design) in formulation R&D?

Answer:
QbD ensures a systematic approach to formulation development by identifying critical quality attributes (CQAs) and process parameters. It enhances product quality, consistency, and regulatory compliance.

7. How do you ensure content uniformity in OSD formulations?

Answer:
Content uniformity is ensured through:

• Proper mixing techniques.
• Monitoring particle size distribution.
• Controlling granule flow properties.
• Using in-process testing like NIR spectroscopy.

8. What are the critical factors in tablet coating, and how do you optimize them?

Answer:
Critical factors include:

• Coating solution composition.
• Spray rate and atomization.
• Airflow and temperature.
  I optimize these through small-scale trials, process design, and monitoring coating uniformity.

9. How do you handle hygroscopic drugs during formulation?

Answer:
I use techniques like:

• Selecting moisture-resistant excipients.
• Packaging with desiccants.
• Modifying granulation techniques to reduce moisture uptake.

10. What is your experience with stability studies for OSD?

Answer:
I design stability protocols as per ICH guidelines, testing physical, chemical, and microbiological stability under accelerated and long-term conditions. This helps determine shelf life and packaging requirements.

11. Explain the process of developing sustained-release formulations.

Answer:
Sustained-release formulations are designed to release the drug over an extended period. Techniques include:

• Matrix systems using hydrophilic or hydrophobic polymers.
• Coating with controlled-release polymers.
• Use of osmotic pumps.

12. What role do dissolution studies play in formulation development?

Answer:
Dissolution studies evaluate the drug release profile, ensuring consistency and bioavailability. They guide formulation optimization and support bioequivalence studies.

13. How do you approach troubleshooting issues like capping or lamination during tablet compression?

Answer:

• Capping/Lamination causes: Poor granule compressibility, trapped air, or inappropriate tooling.
• Solutions: Adjusting compression force, improving granule properties, or using pre-compression steps.

14. Can you describe your experience with regulatory requirements for OSD development?

Answer:
I ensure compliance with guidelines like ICH Q8 (Pharmaceutical Development) and regional requirements (e.g., FDA, EMA). Documentation includes master formulas, batch records, and stability data for submission.

15. How do you approach taste masking in OSD formulations?

Answer:
I use techniques like:

• Coating particles with taste-masking polymers.
• Using sweeteners or flavoring agents.
• Complexation with cyclodextrins or ion-exchange resins.