A list of interview questions and answers for pharma jobs (Formulation Development)

Q1. What is Preformulation study?

-      Preformulation study is a group of studies that focus on the physicochemical properties of a new drug candidate that could affect the drug performance and the development of a dosage form.


Q2. Which parameters are found out in Preformulation study?

Appearance, Molecular weight, Solubility, pH, Hygroscopicity, Flowability, Bulk density, Incompatibilities etc.


Q3. What is BCS classification?

Biopharmaceutical classification system is a system to differentiate the drugs on the basis of their solubility and permeability.


Q4. Why BCS classification is important?

BCS predict in vivo performance of drug products from in vitro measurement of solubility and permeability.


Q5. What is the application of Henderson-Hasselbalch (HH) equation?

Henderson-Hasselbalch (HH) equation is frequently used to determine the pH of a solution.


Q6. How can calibrate a HPLC?

-          A HPLC can be calibrated through the following checking:

·         Flow rate (pump) accuracy checking

·         Gradient accuracy checking

·         Pump leakage checking

·         Wavelength accuracy checking

·         Detector intensity (linearity)

·         Auto sampler injector linearity

·         Degree of reproducibility etc.


Q7. How classify ICH climate zones?

-          Depending on the annual temperature and humidity, the world is divided into following climate zones:

  •      I.            Temperate zone: 21̊C, 45%
  •    II.            Subtropical zone: 25̊C, 60%
  •   III.            Hot-dry zone: 30̊C, 35%
  •  IVa.      Hot humid zone: 30̊C, 60%
  •  IVb.      Hot higher humid zone: 30̊C, 75%

Q8. When intermediate stability study is omitted?

If 30°C ± 2°C/, 65% RH ± 5% RH is the long-term (real time) condition, there is no intermediate condition.

 Q9. What is stress testing?

-          Stress testing of the drug substance can help identify the likely degradation of products, which can in turn help establish the degradation pathways and the intrinsic stability of the molecule and validate the stability indicating power of the analytical procedures used.

-          Stress testing is likely to be carried out on a single batch of the drug substance. It should include the effect of temperatures (in 10°C increments (e.g., 50°C, 60°C, etc.) above that for accelerated testing), humidity (e.g., 75% RH or greater)

Q10. Which source of Povidone mostly used?

-          BASF Germany.


Q11. Which amount Povidone used as a binder?

-          2-5%

Q12. What is the combination of Ludipress?

-          Lactose + Povidone K-30 + Crospovidone


Q13. Who is the manufacturer of Ludipress?

-          BASF Germany.


Q14. What is TGA?

Thermo gravimetric analysis is a method of thermal analysis in which the mass of a sample is measured over time as the temperature changes.

Q15. What’s impact of TGA on formulation development?

  • -        Provides information about physical phenomena (phase transition, absorption, desorption), chemical phenomena (chemisorptions, thermal decomposition), and solid-gas reaction (oxidation, reduction).
  • -         Characterize and quantify the moisture content.
  • -          Decomposition mechanism for various polymeric preparations.
  • -          Prediction of stability of drug.

Q16. What is RLD?

-       Reference Listed Drug (RLD) is an approved drug product to which new generic versions are compared to show that they are bioequivalent.

Q17. Which information’s available in RLD?

-          Qualitative formulation, Coating materials, Packaging materials, Storage condition etc.

Q18. Which parameters are determined in Preformulation study?

-         Molecular weight, Hygroscopicity, Solubility, pH, Storage condition, Incompatibility etc.


Q19. Why molecular weight determination is needed for generic drug development?

-         To determine the factor of an Active ingredient.

Q20. What is glass transition temperature (Tg)?

-        The temperature region where the polymer transition from a hard, glassy material to a soft, rubbery material.

Q21. What is pH dependent solubility and why it’s important?

-      pH dependent solubility means the solubility of a substance depends on pH variation. In general, dissolution of BCS class II drugs is dependent on a wide variety of physiological factors. pH, ionic strength, and buffer capacity are three major characteristics of the GI fluids that can affect the rate of drug release.


Q22. What do you mean by Hygroscopicity?

-        Hygroscopicity is the ability of a material to interact with moisture from the surrounding atmosphere.


Q23. What type of measurement should be taken for hygroscopic material?

  • -          Relative humidity should be under control (<45%).
  • -          Wet granulation should be omitted.

Q24. What do you mean by QbD?

-        design a quality product and its manufacturing process to consistently deliver the intended performance of the product.

Q25. What are the tools of QbD?

  • Quality Target Product Profile (strength, rout of administration, PK parameters, Sterility, Purity, Dissolution, Assay)
  • Critical Quality Attributes (particle size, distribution, bulk density, moisture content, and which are affect on product purity, strength, stability etc.)
  •  Risk Assessment: Linking Material Attributes and Process Parameters to Drug Product CQAs
  • Design Space
  • Control Strategy  
  • Product Lifecycle Management and Continual Improvement

Q26. What do you mean by Technology Transfer?

-          Transfer of new technology from the originator to a secondary user.

Q27. How can identify the physical incompatibilities of pharmaceutical formulation?

-          Stress testing may identify the physical incompatibilities of new drug formulation.

Q28. Which parameters are affected by Physical and Chemical interaction of Drug-Excipients?

-          Any physical or chemical interaction between drug and excipient can affect bioavailability and stability of drug.

Q29. Why we use cellulose derivatives in Oral solid dosage formulation?

-          To control or modify the drug release profile.


Q30. How can overcome the BCS class IV material problems?

-          BCS class IV drugs are generally not suitable for oral drug delivery or else some special drug delivery technologies such as Nano-suspensions will be needed.

Q31. What is process validation?

Process validation is the analysis of data gathered throughout the design and manufacturing of a product from validation batches to confirm that the process can reliably output products of a determined standard.

Q32. What do you mean by Biosimilar (drug)?

A biosimilar is a biologic medical product that is almost an identical copy of an original product with the same active substance that is manufactured by different company.

Q33. What is cytotoxicity?

-          Cytotoxicity is the quality of being toxic to cells.

Q34. How can claim the shelf life of Pharmaceutical Product?

-          Depending on the accelerated and intermediate stability study we can claim the shelf life of a pharmaceutical product. When a product is physically and chemically stable at 6 months accelerated study (40/75) and 12 months intermediate study (30/65) we can claim 2 years shelf life. But if found any significant change in 12 months intermediate study we need to follow up long term/real time study.

Q35. What do you mean by forced degradation?

-          Forced degradation is a degradation of new drug substance and drug product at conditions more severe than accelerated conditions.

Q36. What is predictable dissolution?

-          Predictable dissolution is the in-vitro dissolution study. Which predicts the in-vivo dissolution (drug release) rate.

Q37. Can SLS hamper dissolution?

-          Yes, sometimes SLS can hamper the dissolution rate. Especially dissolution rate of gelatin capsule is hampered by SLS. Clarithromycin dissolution rate also hampered by SLS.

Q38. Which co-solvents are commonly used in oral solution preparation?

-          Propylene glycol, Glycerol, Ethanol, PEG.

Q39. What are common buffer salts used in oral solution preparation?

  • -          Acetates (acetic acid, sodium acetate), 1-2%
  • -          Citrates (citric acid, sodium citrate), 1-5%
  • -          Phosphates (sodium phosphate, disodium phosphate), 0.8-2%

Q40. What antioxidants are commonly used for aqueous and oil bases solution preparation?

  • -          For aqueous solution: Sodium sulfite, Sodium metabisulfite, Sodium formaldehyde sulfoxylate, and Ascorbic acid.
  • -          For oil base solution: Butylated Hydroxytoluene (BHT), Butylated Hydroxyanisole (BHA), and Propyl Gallate.
  • -          Typically antioxidants are employed in low concentrations (< 0.2% w/w).

Q41. What types of drug excipient interactions are occurred? 

  • Physical interaction (Complexation, Adsorption, Solid dispersion).
  • Chemical interaction (Oxidation, Isomerization, Photolysis, Polymerization).
  • Biopharmaceutical interactions (Premature breakdown of enteric coat, Increase in gastrointestinal motility, Interactions due to adjunct therapy).

Q42. For which drugs disintegration test is exempted?

-          Modified or delayed release drugs

Q43. What is HLB value? And for which products it’s important?

-          Hydrophilic-lipophilic balance (HLB) value is a measure of the degree to which it is hydrophilic or lipophilic. It’s help in the selection of a proper surfactant. Especially for emulsion and suspension preparation.

  • -          HLB value <10 indicate lipid soluble.
  • -          HLB value >10 indicate water soluble.
  • -          HLB value 1 to 3 indicates anti-foaming agent.
  • -          HLB value 3 to 6 indicates W/O emulsifier.
  • -          HLB value 7 to 9 indicates wetting agent.
  • -          HLB value 13 to 16 indicates detergent.
  • -          HLB value 8 to 16 indicates O/W emulsifier.

Q44. How do you differ between Vitamins and Minerals?

-          Vitamins are organic and can be broken down by heat, air or acid. Minerals are inorganic elements that come from the soil and water absorb by plants or eaten by animals.


Q45. How to determine difference and similarity factors of two products and what’s effect on bioequivalent product?

  • -          Using the mean dissolution values from both curves at each time interval, calculate the difference factor (f1) and similarity factor (f2).
  • -          For curves to be considered similar- f1 values should be close to 0, and f2 values should be close to 100.
  • -          Generally, f1 values up to 15 (0-15) and f2 values greater than 50 (50-100) ensures sameness or equivalence of the two curves.
  • -          At least 12 units should be used for each profile determination.


Q46. How can ensure that the bioavailability of the drug is not limited by dissolution?

-          The BCS suggests that for high solubility, high permeability (class 1) drugs and in some instances for high solubility, low permeability (class 3) drugs, 85% dissolution in 0.1N HCl in 15 minutes can ensure that the bioavailability of the drug is not limited by dissolution.

Q47. How to measure bioavailability of a product?

-          Bioavailability is usually measured by the area under the blood or plasma concentration time curve (AUC) and the maximum concentration (Cmax) respectively.

Q48. Which is identified by PK and PD parameters?

  • -          PK describing the relationship between dose, systemic drug concentration and time.
  • -          PD describing the relation between systemic drug concentration and the effect vs. time profile.

Q49. Why BCS is important for formulation development?

The knowledge of the BCS characteristics of a drug in a formulation can help a formulation scientist to develop a more optimized dosage form based on fundamental mechanistic, rather than empirical information.

Q50. What is ANDA?

Abreviated New Drug Application contains data that, when submitted to FDA's center for drug evaluation and research, review and ultimate approval of generic drug product. Once approved, an applicant may manufacture and market the generic drug product to provide a safe, effective, low cost alternative to the American people.


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