Interview questions for quality assurance in pharmaceutical industry

Interview questions for quality assurance in pharmaceutical industry:

We have provided interview questions for quality assurance in pharmaceutical industry here. There is no specified differences between quality control and quality assurance from interview point of view. They are all interlinked. But we tried to prepare in separate posts and produced. This post is an extension to our previous interview questions for quality assurance in pharmaceutical industry. If you attending an interview, you have to all these questions and answers in these 4 posts. It helps you a lot to face interview well.

Interview questions for quality assurance in pharmaceutical industry are as follows.

Qa-What do you know about change control?

Changes which were made to materials or procedures or methods or equipment or software should be documented properly. These changes should approved, validated and able to traceable. Change control deals and makes sure all these changes.

Explain about Bracketing and Matrixing study designs in stability testing/

Ans) These are the study designs for stability testing. In a full study design, you have to test the samples of all the design factors at all time points. Bracketing and Matrixing are reduced study designs.

When multiple design factors involved in a study, these are the best alternatives to full study design. If you use these designs, you need not to test all the samples at all time points. These study designs mostly used when multiple design factors involved.

Bracketing: In this schedule, At all time points only extremes of certain study factor (like container fill & or container size or strength etc) samples tested. Bracketing supposes that tested extremes stability represents the intermediate levels stability of that study factor.

Matrixing: In this schedule, at a specific time point a selected subset of the total number of possible samples for all factor combinations would be tested. At a next or subsequent time point, all the factor combinations for another subset would be tested. Matrixing supposes that at a given time point, tested each subset stability represents the all the samples stability.

Before using this study designs, certain assumptions should be evaluated and justified.

NOEL: No Observed Effect Level

MACO: Maximum Allowable Carry Over


Corrective Action and Preventive action. It’s an important part of QMS (Quality Management System). Corrective actions planned to know the cause of the problems which were happened in the past and correct it. Preventive actions intended to prevent the problems that might happen in the future.

Explain about Out of Specification (OOS) results and Out Of Expectation (OOE) results?

Out Of Specification (OOS) results: Analysed test result falling out side the predefined acceptance range or criteria made by company documentation or official compendia.

Out Of Expectation (OOE) results: Although the Analysed test result falls within the specification, this result will falls out side the procedure expected variability.

Interview questions for quality assurance in pharmaceutical industry 

Interview questions for quality assurance in pharmaceutical industry:

Stress Testing:

Also called as Forced degradation study, stress study. Forced degradation study intended to know the degradation products, it will helps us further to know the molecule intrinsic stability, degradation pathways establishment and to validate the molecule stability procedures. Stress testing conducted at the conditions which are more severe than the accelerated study conditions. For a formal stability program, stress testing not considered as a requirement. It is regulatory authority requirement.

What is the purpose/use(s) of stability testing?

Ans) Stability testing gives the confirmation as how the quality of study product changes with time.

It finds out the study product shelf life, recommended storage conditions as well as container closure system suability. Also gives assurance to the patient regarding stability of a drug product. Stability testing is a regulatory requirement also.

What are different types of stability studies along with its conditions?


Long-term stability studies: Storage conditions 25+20C, 60+5% RH and Minimum Time period is 12 months

Intermediate stability studies: Storage conditions 30+20C, 60+5% RH and Minimum Time period is 6 months

Accelerated stability studies: Storage conditions40+20C, 75+5% RH and Minimum Time period is 6 months

Dead leg: Dead logs not allowed in water design systems. These are the stagnant areas with no water flow. It allows microbial contamination resulting the surface colonisation by forming biofilms. If a dead log present in any case, it should have particular pipe diameter and velocity. In general agreement in industry, dead log should not be more than the pipe diameter.

For e.g: If the pipe diameter is 5 cm , then dead log should not be more than 10cm.

Cleaning validation: It is a documented evidence involves the approved cleaning procedure for eliminating the process equipment contaminants. It means the process equipment ready and can be used safely for preparing the next product without any previous contaminants.

These contaminants may be chemical (previous product residues), microbial or Physical (Particulate matter) types. Different types of cleaning agents used in the cleaning validation like aqueous solvents (water, surfactants, acids or bases etc) and organic solvents.

Validation master plan (VMP):

It is a document describes the company’s validation strategy and approach for establishing the performance adequacy. VMP includes all the details and time scales regarding the validation work to be performed.

Process validation:

It provides a documented evidence assuring that a particular process produces a product with predetermined specifications and characteristics consistently.

Four types of process validation available.

Prospective validation: Conducted prior to process implementation to assuring that process is performs as intended on the basis of pre-planned plans.

Concurrent validation: Conducted during the product routine production.

Retrospective validation: Conducted on some products , those products which are already on commercial market. The intention is to establish the long term compliance of that product.

Re-validation: This is nothing but repetition of validation. Conducted to assuring that the changes/modifications done in equipment/process in according to the change control procedures. Those changes are not effecting the equipment/process and their produced products adversely.

This is the second post regarding Interview questions for quality assurance in pharmaceutical industry. You can view the previous post  QA interview questions and answers.

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Interview questions for quality control analyst in pharma industry

Interview questions for quality control analyst in Pharma Industry

We have provided interview questions for quality control analyst here. You have to know all these question answers before attending an interview. We have already provided interview questions for quality control analyst in our previous post. This post includes some more important questions for interview. These are useful for freshers as well experienced people. Have a knowledge on all these questions before attending the interview.

interview questions for quality control analyst are as follows.

Acceptance Limit for Friability of tablets?

Ans) Acceptable tablets weight loss is 0.5 to 1.0% for 100 revolutions. Or 1-5% weight loss for 10 minutes revolution. ( Generally 6 grams of weighed and de dusted tablets place in the rotating apparatus, it revolves at a speed of 25 revolutions per minute i.e 25 rpm. Tablets freely falls from 6 inch height for every rotation. These tablets subjected to 100 rotations or for 10 minutes i.e 250 rotations (10 min*25rpm)).

Acceptance limit for uniformity of content of tablets?

Ans) There are two criterias for acceptance limit.

Take 30 randomly selected tablets. Take 10 tablets, and assay individually. 9 out of 10 tablets should be in the range of 85% to 115%. One tablet can be in the range of 75%-125%. If this criteria fits, it passes the test. If these conditions not met, remaining 20 tablets should be assayed. All of the 20 tablets should in the range of 85% to 115%.

What are different types of capsule sizes and holding capacity of smallest and largest size?

Ans) Sizes are 000, 00 , 0, 1, 2, 3, 4, 5.

Smallest size 5, It can hold at least 65 mg of drug.

Largest size 000, It can hold up to 1000 mg of drug.

What are the types of Gas Chromatography?

Ans) Two types available.

Gas Solid chromatography(GSC) : Stationary phase is solid and gas used as mobile phase.

Gas Liquid chromatography(GLC): Liquid on a thin solid support used as stationary phase and gas used as mobile phase.

Which material used as stationary phase and mobile phase in GSC and GLC ?

Ans) Granular silica, alumina or carbon used as stationary in phase in GSC. Non volatile liquid on solid base like Diatomaceous earth or kieselghar used as stationary phase in GLC. Inert gases like helium or nitrogen used as mobile phase(carrier gas) in both GSC and GLC.

which type of tablets does not require Disintegration test?

Ans) Sustained release tablets, Delayed released tablets and Chewable tablets.

interview questions for quality control analyst

What is disintegration time for Uncoated , coated, enteric coated, dispersible and soluble tablets?

Ans) Uncoated tablets – 30 min (Uses water as medium at 37+20C temperature)

Coated tablets- 30 min (Uses water as medium at 37+20C temperature)

Enteric Coated tablets- 60 min (Uses mixed phosphate buffer at 37+20C temperature) or It should no disintegration for 2 hours (Using in 0.1N Hcl as medium at 37+20C temperature)

Dispersible tablets – 3 min (Uses water as medium at 19 to 210C temperature)

Dispersible tablets – 3 min (Uses water as medium at 19 to 210C temperature)

What is disintegration time for soft gelatin and Hard gelatin capsules?


Soft gelatin capsules- 60 min (Uses water as medium at 210C temperature)

Hard gelatin capsules – 30 min (Uses water as medium at 210C temperature)

Accuracy VS Precision:

Accuracy also known as trueness. Analytical Procedure accuracy is the closeness between the accepted reference value or conventional true value and the result value. One measurement is enough to determine the accuracy of an analytical procedure. It does not tell about the quality.

For accepted reference value is 20, you result value is 19.9 or 20.1. Then it is said as high accuracy.

In the same case, your result value is 18.7 0r 21.4. Then it is stated as low accuracy.

Precision: Analytical Procedure precision is the closeness between a number of measurements taken  from the homogenous sample multiple samplings under specified conditions. To measure the precision of an analytical procedure requires several measurements. It speaks about the quality.

For ex: From a homogenous sample, you have measured multiple samples, the values you obtain is

A. 19.2, 19.4, 19.3, 19.2, 19.1

B. 10.2, 10.4, 10.3, 10.2, 10.1

C. 19.2, 22.4, 16.6, 17.1, 16.9

In the above options, Result “A”& “B” said as High precision, Result “C” said as Low precision. Here the consideration is series of measurement values for a particular homogenous sample. There is no reference value in the concept of precision.

Differentiate between relative humidity and absolute humidity?

Ans) Absolute humidity also called as Humidity. Simply defined as amount of water vapour (moisture) present in a volume of air. Unit expressed as gram/m3.

“Relative” humidity: “Relative” nothing but comparison or ratio. So it is expressed in percentage(%). It is the ratio of air current water vapour/moisture/humidity to highest possible water vapour /moisture/ humidity. This highest possible humidity depends upon the current specific air temperature.

Ex: Current air contains 1 gram/m3 of water vapour (humidity), For that air it can hold up to 4 gram/m3 of water vapour (humidity) (It depends on temperature).

Relative humidity = ¼*100 = 25%


Limit of Detection: Also known as Detection Limit. For a particular analytical procedure, Upto how much lowest amount of component or analyte  in a sample can be detected. That is the detection limit for that individual or particular analytical procedure. It does not mean that it should able to quantitate that analyte.  It should able to detect that analyte, that’s it.

LOQ: Limit of Quantitation: Also known as Quantitation Limit. For a particular analytical procedure, up to how much lowest of analyte in sample can be quantitated with suitable accuracy and precision. LOQ come into picture in quantitative assays to determine the degraded products or impurities in the samples.

Related: QA interview questions and answers 

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