Category: Interview Questions

Title:-Interview Questions

 

1. What are difference between calibration & validation & qualification?

Calibration – The set of operations that establish under specified conditions the relationship between values indicated by an instrument or system for measuring and corresponding values of reference standard.

Validation- Action of proving & documenting that any process actually & consistently leads to expected results.

Qualification – Action of proving & documenting that any premises, systems & equipments are correctly installed & lead to expected results.

2. Define CAPA?

Corrective and preventive actions

3. What is the difference between drug purity & potency?

Purity: it is the absence of unwanted substances like impurities & contaminants

Potency: it is a measure of drug activity measured in terms of amount of drug required to produce an effect.

4. Which gases are used in GC?

Helium & Nitrogen.

5. What is the difference b/w temp change control & deviation?

Change control: it’s planned/permanent change after assessing the impact on other functions.

Deviation: unplanned/Temporary change.

6. What is friability?
Ans: The percentage of loss mass of a solid dosage form after 100 times revelation in 4 minutes due to friabilizer is called Friability.

7. What is hardness?
Ans:Required energy for break a Solid dosages form on their edge.

8. What is pH?
Ans: pH/pOH is the negative logarithm of Hydrogen ion/Hydroxyl ion concentration. Measurement of pH of any aqueous sample solution gives the degree of acidity or alkalinity of the solution. Mathematically it may be represented as follows;

pH= – log [ H+ ].
pOH = – log [OH- ]

9. Why pH is important in pharmaceuticals?
Ans: pH is important in pharmaceuticals because some active ingredient is stable in one pH and degrades in another
pH. So in-case of product stability pH is an important factor.

10. What is dissolution?
Ans: The process by which the solid particle or medicament are dissolve in suitable solvent for ease of absorption.

11. Difference between Dissolution and Assay?
Ans: Dissolution- is the amount of drug released in a certain period of time from a dosage form on the other hand
Assay- is the amount of drug that is contained by a unit dosage form of medicament.

12. What is disintegration? Importance in pharmaceuticals dosage form?

Ans: Breakdown of unit solid dosage form or larger granules into smaller one (smaller than 2 mm).

In most cases dissolution is directly proportional to the disintegration. More faster the solid dosage form disintegrates, more faster it
dissolve and goes into the systemic circulation and gives the therapeutic response.

13. What do you mean by DQ, IQ, OQ, & PQ ?

Design Qualification (DQ): documented verification that the proposed design of the facilities, equipment, or systems is
suitable for the intended purpose.

Installation Qualification (IQ): documented verification that the equipment or systems are installed or modified &
comply with the approved design of the manufacturer’s recommendations and/or user requirements.

Operational Qualification (OQ): documented verification that the equipment or systems are installed or modified &
perform as intended throughout the anticipated operating ranges.

Performance Qualification (PQ): documented verification that the equipment and ancillary systems are connected &
can perform effectively and reproducibly based on the approved process method and specifications.

14. Define complaint & recall?
All quality related complaints of a product from the market should be recorded & investigated accordingly to written procedure.
Recall is the removal from the market of specified batches or all batches of a product.

15.Define Corrective Action & Preventive Action (CAPA) ?

Corrective Action : Action taken to rectify, fix or correct a specific deviation, defect or undesirable situation.

Preventive Action : Action taken to eliminate the cause of deviation, defect, or other undesirable situation in order to prevent the future occurrence of such or similar an event.

16. What is self inspection?
Self inspections is conducted by internal team in order to monitor the implementation and compliance with Good Manufacturing Practice principles and to propose necessary corrective measures.

17. Define Stating Materials, Intermediate , Bulk & Finished Products ?
Stating Materials : A starting material is known as raw material or an API. A substance is a defined quality which used in production of a pharmaceutical product & non-pharmaceutical product excluding packaging material.

Intermediate : A partly processed material that must undergo the further manufacturing steps before a bulk product.

Bulk Product : Any product that has completed all processing steps up to but not including final packaging.

Finished Products : A medicinal product, which has undergone all stages of manufacture including packaging.

18. What is the differences between documents & records?
Documents : Document is a controlled written procedure, policy, forms or other pieces of paper as defines a company requirement. & describe how and what to do.

Records : When data or results providing evidence of activities performed then it is recorded.

19.What is HVAC system & its functions?

Heating, Ventilating and Air Conditioning system is used for temperature and humidity control with in a manufacturing
environment.

20. What is SOP? Why it is needed ?
SOP (Standard Operating Procedure): A written approved procedure which gives instruction for performing operation/task not necessarily specific to a given product or material but of a more general matter.

21. What is Clean Room?
A room in which the concentration of airborne particles is controlled to meet specified airborne particulate cleanliness class.

22. What is Aseptic Area?
Any area is an aseptic for which airborne particulate and microorganism levels are controlled to specific levels appropriate to the activities conducted within that environment.

23. What is Air lock?
Airlock: An enclosed space with two or more doors, which is interposed between two or more rooms.

24. What Is Site Master File ?

Site Master File is prepared by the manufacturer and contains specific information about the quality assurance, the production and/ or quality control of pharmaceuticals manufacturing operations carried out at the named site and any closely integrated operations at adjacent and nearby buildings. It only part of a pharmaceuticals operation is carried out
on the site.

25. What are the differences between Sanitization and Sterilization?

Sanitization:
Reduction the number of micro-organism to a safe or relatively safe level as determined by applicable, regulations or
the purpose of application

Sterilization: Sterilization is a process or technique to remove bacteria and all types of viable microorganism.

26. What are the parameters performed during Analytical Method validation?
Accuracy, Precision, Specificity, Detection Limit, Quantitation Limit, Linearity & Range, Ruggedness & System suitability Testing.

27. what is HEPA filters?

High Efficiency Particulate Air .High Efficiency Particular Air Filter (HEPA) is a air filtering system. HEPA filter
capable of retaining 99.97 percent of particles as small as 0.3 μm.

28. what is DOP?

DOP : Dioctyl Phthalate .Dioctyl Pthanate test is used to determine the integrity of HEPA filters.

29. What is difference between QA and QC ?
Quality Assurance(QA)  is the section  made with the objective of ensuring that pharmaceutical products are of the quality required for their intended use .QA therefore incorporates GMP and other factors such as product design and development, GLP and GCP.

Quality Control (QC) is the section where the product is actually tested for expected behavior or standards as per defined specifications.

30. What is Contamination?
An undesired introduction of impurities of a chemical or microbiological nature ,or of foreign matter, into or on to a starting material or intermediate during production , sampling , packaging or repackaging, storage or transport.

31. What is the composition of a C18 column?

Octadecyl carbon chain bonded with silica.

32. What do you mean by LOD and water content?

LOD is the loss during drying of sample as per prescribed conditions which gives loss (presence) of all evaporating solvents along with water.It is the dry base.

Water Content gives the moisture present in the sample only. It is anhydrous base.

33. Why we use toluene for resolution in UV calibration?

Toluene gives Maxima and Minima at 266nm and 269nm to check resolution in UV calibration. Hexane used  as a diluents because it has no UV absorbance.

34. Why we use disodium tartare for determination of factor in karl fischer titration?

Disodium Tartrate is used as a primary standard substance for the standardization because of the following properties:

1. Available in a stable crystalline hydrate form.

2. Its water content is close to theoretical value.

3. Substances in nearly 100% purity.

4. More favorable gravimetric factors.

5. Stable at extreme humidity.

6. It is relatively insoluble in absolute methanol

7. Its water content is rapidly and quantitatively titrated to a sharp end point.

35. What are closely monitor parameters in stability study? Temperature and Relative Humidity.

36. What does u mean by MACO & NOEL level?

MACO-Maximum Allowable Carryover

NOEL-No Observed Effect level

both terms are used in cleaning validation to set limits.

37. What is Process validation?

Establishing a documented evidence with high degree of precision that specific process will consistently produce a product which meets its predetermined specifications & quality parameters.

38. What are stability zones & climatic conditions?

Zone-1:(Temperate Region)

Great Britain/north Europe/Canada/Russia (Temp-21/ RH-45%)

Zone-2: (Subtropical/Mediterranean Region)

USA/Japan/South Europe (Temp-25/ RH-60%)

Zone-3: (Hot & Dry Region)

Iran/Iraq/Sudan/India (Temp- 30/ RH- 55%)

Zone-4: (Hot & Humid Region )

Brazil/Ghana/Nicaragua/Philippines (Temp-30/ RH -70%)

39. What is photo stability?

It was study performed to evaluate & demonstrate that light exposure doesn’t result in unacceptable change in new drug substances.

40. What is the wave length of polarimeter lamp?

589.3 nm.

41. Which gases are used in Gas Chromatography?

Helium, Hydrogen & Nitrogen.

42. What is dead leg? 

A dead leg is defined as an area in a piping system where liquid can become stagnant and not be exchanged during flushing.

43. How many Tablets shall be taken for checking friability? 

For tablets with unit mass equal or less than 650 mg shall take sample of whole tablets corresponding to 6.5g.

For tablets with unit mass more than 650 mg shall take a sample of 10 whole tablets.

44. What is the formula for calculating weight loss during friability test? 

%Weight Loss = Initial Weight – Final Weight X 100_____                                                                Initial Weight

45. Why do we calibrate a qualified equipment/instrument on definite intervals?

An equipment or instrument can ‘drift’ out of accuracy between the time of qualification and actual use. So it is recommended to calibrate and recalibrate the measuring devices and instruments on predetermined time intervals, to gain confidence on the accuracy of the data.

46. Why do we consider three consecutive runs/batches for process validation?

The number of batches produced in the validation exercise should be sufficient to allow the normal extent of variation and trends to be established and to provide sufficient data for evaluation and reproducibility. · First batch quality is accidental , · Second batch quality is reproducible , · Third batch quality is validation (confirmation).

47. What is bracketing & matrixing in stability testing?

Both Matrixing & Bracketing’s are reduced stability testing designs Bracketing The design of a stability schedule, such that only samples of extremes of certain design factors (ex:strength,package size) are tested at all time points as in full design.The designs assumes that the stability of any intermediate level is represented by the stability of extremes tested. Matrixing The design of a stability schedule, such that a selected subset of possible samples for all factor combinations is tested at a specified time point.At a subsequent time point another subset of samples for all factor combination is tested. The design assumes that the stability of each subset samples tested represents the stability of all samples at a given time point. There for a given time point other than initial & final ones not every batch on stability needs to be tested.

48. What is Capping in Tablets?
• It is partial or complete separation of the top or bottom of tablet due air-entrapment in the granular material.

49. What is Lamination in tablets?

• It is separation of tablet into two or more layers due to air-entrapment in the granular material.
• Is the separation of a tablet into two or more distinct horizontal layers.

50. What is Chipping in tablets?

• Chipping‘is defined as the breaking of tablet edges, while the tablet leaves the press or during subsequent handling and coating operations.

51. What is CRACKING in Tablets?

Small, fine cracks observed on the upper and lower central surface of tablets, or very rarely on the sidewall are referred  as Cracks.

52. What is MOTTLING in Tablets?
• Mottling‘is the term used to describe an unequal distribution of colour on a tablet.

53. What are the recommended storage conditions for empty hard gelatin capsules?
Ans: Temperature;15 – 25 C & Humidity;35 -55% RH.

54. Limit of detection (LOD): The lowest amount of analyte in a sample which can be detected but not quantitated as an exact value.

55. Limit of quantitation (LOQ): The quantitation limit of an individual analytical procedure is the lowest amount of analyte in a sample which can be quantitatively determined with suitable precision and accuracy.

56. Precision: The precision of an analytical procedure expresses the closeness of agreement (degree of scatter) between a series of measurements obtained from multiple sampling of the same homogeneous sample under the prescribed conditions.

57. Repeatability: Repeatability expresses the precision under same conditions: same analyst, same apparatus, short interval of time, identical reagents.

58. Reproducibility: The reproducibility expresses the precision under different conditions for instance: laboratories, reagents from different sources, analysts, days, apparatus from different manufacturers, etc.

59. Ruggedness: The degree of reproducibility of test results obtained by the analysis of the same samples under change in equipment, laboratory, and analyst.

60. Robustness: Robustness of an analytical procedure is a measure of its capacity to remain unaffected by small, but deliberate, variations in method parameters and provides an indication of its reliability during normal use such as different  temperatures, mobile phase compositions, flow rates, or injection volumes etc.

61. Specificity: Specificity is the ability to assess unequivocally the analyte in the presence of components which may be expected to be present. Typically these might include impurities, degradants, placebo matrix, etc.

62. Expiry date – The date given on the individual container (usually on the label) of a drug product up to and including which the product is expected to remain within specifications, if stored correctly.

63. Retest date – The date when a material should be re-examined to ensure that it is still suitable for use.

64. Bioburden:-
The total number of microorganisms associated with a specific item prior to sterilization.

65. Colony Forming Unit (CFU):-
A microbiological term that describes the formation of a single macroscopic colony after the introduction of one or more microorganisms to microbiological growth media. One colony forming unit is expressed as 1 CFU.

66. Decontamination:-
A process that eliminates viable Bioburden via use of sporicidal chemical agents.

67. Disinfection:-
Process by which surface Bioburden is reduced to a safe level or eliminated.

68. Component: Component means any ingredient intended for use in the manufacture of a drug product including those that may not appear in such drug product.

69. Drug – Product: ‘Drug Product’ means a finished dosage forms (e.g. Tablet, Capsule, Solution etc.) that contains an active drug ingredient generally but not necessarily in association with inactive ingredients.

70. Active Ingredients: Active ingredient means any component that is intended to furnish pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment or prevention of disease or to effect the structure of any function of the body of man or other animals.

71. Excipient: Excipients are the additives/no drug component used to convert pharmacologically active compounds in a pharmaceutical dosage forms suitable for administration of patients.

72. Inactive Ingredient: ‘Inactive ingredient’ means any component other than an active ingredient.

73. Bulk Product: Any products, which has completed all processing stages up to, but not including final packing. Any processed product, which still has to undergo the packing operation in order to become a
finished product.

74. Finished Product: A medicinal product, which has undergo all stages of manufacturing operations including  packaging in its final container and labeling.

75. Strength: Strength means the concentration of the drug substances (for e.g. weight/ weight, weight / volume or unit dose and or the potency of a drug product).

76. Potency: Potency means the therapeutic activity of the drug product as indicated by appropriate laboratory tests or by adequately developed and controlled clinical data.

77. Efficacy:  It is a term used to know the response of any drug produced whether optimum or not.

78. Theoretical Yield: ‘Theoretical Yield’ means the quantity that would be obtained at any appropriate stage of manufacturing, processing or packing of a particular drug product.

79.Actual Yield: ‘Actual Yield’ means the quantity that is actually produced at any appropriate phase of manufacture, processing or packing of a particular drug product.

80. OTC Drug: Over the Counter Drug. OTC drugs are those drugs which can be used without the prescription of a registered physician.

81. Optical Rotation: The optical rotation of a substance is the angle through which the plane of polarization is rotated, when polarized light is passed through a chemical substance.

Dextro-rotation is designated (+) and Levo-rotation is designated (-).

82. Fumigation: Fumigation is the process to reduce microbial load in a particular area by using poisonous fumes or gases to destroy living organisms.

83. Accuracy:  The closeness of the result obtained during measurement or analysis to the its true value.

84. Conductivity:

Conductivity is the measurement of materials ability to conduct electric current. Measurement of conductivity of sample solution gives the degree of electrical conductance in a defined volume of the solution.

85. Potable Water: Potable water is drinking water, treated by the local authority or an site, which is suitable for human consumption.

86. DM Water: DM Water stands for Demineralized water. The water free from minerals is called Demineralized water.

87. Water For Injection: Water for injection is intended to a high degree of chemical purity and to be free from pyrogenic
substances and endotoxin.

88. TDS: TDS means Total dissolve solid. The amount of solid present in dissolved state in DM or Tape water.

89. Pyrogen: In Greek word “Pyrogen” means “Production of fever” any substance that produces a fever.

90. LAL: LAL stands for “Limulus Amoebocyte Lysate” test. This test determines the presence or the concentration of endotoxin in products.

91. Endotoxin: Bacterial Endotoxin or pyrogen is metabolic products of living micro-organism or the dead micro-organism causing a specific pyretic response upon injection.

92. Positive Controls: Positive controls is a culture medium which is used for sterility test is checked for its efficacy to support growth of different organism by adding 10-100 cfu of m gm. This is known as positive control.

93. Negative Controls: Negative controls are the culture media without addition of microbial culture. The –ve control is used to verify the sterility of the medium before, during and after the incubation period of the sterility tests.

94. ATCC (American Type Culture Collection): It is a institution which gives a specific number to different Micro organisms based on the variation of the strain.

95. Positive Pressure: Positive pressure are the pressure created in the aseptic production area to avoid contaminated air pass in.

96. Differential Pressure: Differential Pressure means the pressure difference between two adjacent rooms.

97. Suspension: A suspension is a preparation of finely divided undissolved drugs, dispensed in a liquid phase. It is a two phase dosage system in which a finely divided solid in mixed in desire liquid.

98. Emulsion: Emulsion are usually liquid preparation which are prepared by addition emulsifying agent and purified water to liquid drugs.

99. Suppository: Suppositories are solid preparation intended to insertion in to the rectum, urethra or vaginal cavity. Suppositories are usually prepared by molding uniform mixers of drugs and bases in to a suitable shape. Suppositories melt or soften at body temperature or dissolve slowly in the secretions. Suppositories are usually prepared by by mixing drugs with fat-type bases water-miscible bases or other suitable materials.

100. Ointment: Ointment are usually homogeneous, semisolid preparations for external application that they may be applied to the skin .

101. Cream: Semisolid emulsion system with opaque appearance. It may be a water in-oil or oil in – water type.

102. RSD (Relative Standard Deviation): 

Relative Standard Deviation is given by:

%RSD = (S/X)*100

S= Standard Deviation, X=Mean value.

103. What is Form 482?

FDA may conduct an inspection of your operation for a variety of reasons, such as a routinely scheduled investigation, a survey, or a response to a reported problem. The investigator will present credentials and “Notice of Inspection” upon arriving at your plant.

104. What is Form 483?

An FDA form 483 is issued to firm management at the conclusion of an inspection when an investigator has observed any conditions that in their judgement may constitute violations of the Food Drug and Cosmetic (FD&C) Act and related acts.

105. Out of Specifications (OOS): Results generated during testing that do not comply with relevant standard or specification.

106. Out of Trends (OOT): Any test result obtained for a particular batch that is markedly different from the results of batches in a series.

107. Root Cause Analysis: Root cause analysis is a problem solving technique for identifying the basic or root cause that underlie the occurrence or possible occurrences of an adverse event in a process similar to diagnosis of disease – with the goal always in mind of preventing re-occurrence.

108. Risk Assessment: A systematic process of organizing information to support a risk decision to be made within a risk management process. It consists of the identification of hazards and the analysis and evaluation of risks associated with exposure to those hazards.

109. Prospective validation: Validation conducted prior to the distribution of either a new product, or product made under a revised manufacturing process, where the revisions may affect the product’s characteristics.

110. Retrospective Validation: Evaluation of Established documented evidence that a system does what it purports to do, based on an analysis of historical information.  The evaluation determines the reliability, accuracy, and completeness of a system

111. Concurrent Validation: Occurs Simultaneously with production.

112. what is Audit Trail?

The audit trail is the form of metadata containing information associated with every action that relate to the creation, modification or deletion of GxP records.

113. Critical Process Parameters (CPP): A Process parameter whose variability has an impact on a critical Quality Attributes and thereof should be monitored or controlled to ensure the process produces the desired quality.

114. Critical Quality Attributes (CQA): A Critical Quality Attribute is a physical, chemical, biological or microbiological property or characteristics that should be within an appropriate limit, range or distribution to ensure the desired product quality.

115.Calibration: It is a demonstration that, a particular Instrument or device produces results with in specified limits by comparisons with those produced by a reference or traceable standard over an appropriate range of measurements.

116. What are the Good Manufacturing Practice (GMP) Guidelines?
ICH: Q7 Good Manufacturing Practice
US FDA: 21 CFR Part 210 – cGMP General
211- cGMP for Finished Pharmaceuticals
WHO- Technical Report Series-937
PIC/S- Recommendations PE-009
EU-Part1, Annex5
EU-Part11, Chapter 13

117. What is Molarity ?

• Definition: Number of Moles of substance dissolve in per liter of solution.
• Calculation:

Molarity=   Number of Moles of substance________

Volume of solution in liter

 

118. What is Normality ?

• Definition: Normality is the number of equivalents of a reactive species per liter of solution.
• Calculation:

Normality=   Molarity x n

n=is the number of equivalents per mole.

119. What is Sampling?

Sampling is a process of collecting a small portion of material from a bulk of material received in the form of consignment or whole batch.

120. Primary Packing Materials: Materials which comes in direct contact with the drug product. Eg. PVC, Foils

121. Secondary Packing Materials: Materials which comes in direct contact with primary packing materials. Eg. Cartons, leaflets.

122. Tertiary Packing Materials: Materials which comes in direct contact with secondary packing materials. Eg. Corrugated boxes.

123. Minor defects: A defect that does not affect product safety, purity or identity or package integrity of function.

124. Major defects: A defect that jeopardizes the integrity or function of the package

125. Critical defects: A defect that can compromise product safety, purity or identity that may be harmful to the consumer.

126. What is Hazardous waste?

Waste that is unwanted, unusable and dangerous or potentially harmful to our health or the environment.

127. What is “significant change” in Stability Study?

“significant change” occurs at any time during 6 months testing at the accelerated storage condition.

In general, “significant change” for a drug product is defined as:

1. A 5% change in assay from its initial value; or failure to meet the acceptance criteria for potency when using biological or immunological procedures.

2. Any degradation product’s exceeding its acceptance criterion.

3. Failure to meet the acceptance criteria for appearance, physical attributes, and functionality test (e.g., color, phase separation, resuspendability, caking, hardness, dose delivery per actuation); however, some changes in physical attributes (e.g. melting of creams) may be expected under accelerated conditions; and, as appropriate for the dosage form.

4. Failure to meet the acceptance criterion for pH.

5. Failure to meet the acceptance criteria for dissolution testing at 12 dosage unit.

128. Reagent: Reagent is a substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs.

129. Indicators: Indicators are reagents used to determine the specified endpoint in a chemical reaction which indicates the change in colour, to measure hydrogen-ion concentration (pH) or to indicate the desired change in pH has been effected.

130. Buffer solutions: Buffer solutions are solutions that resist change in the activity of an ion on the addition of substances that are expected to change the activity of that ion.

131. Carbon Dioxide-Free water: It is the purified water that has been boiled vigorously for 5 minutes or more and allowed to cool while protected from absorption of carbon dioxide from the atmosphere.

132. Molar solutions (M): Molar solutions are solutions that contain 1 gram molecule of the compound in 1 litre of solution.

133. Normal solutions (N): Normal solutions are solutions that contain 1 gram equivalent weight of the compound in 1 litre of solution.

134. Percentage weight in weight (%w/w): It expresses the number of grams of solute in 100 g of product.

135. Percentage weight in volume (% w/v): It expresses the number of grams of solute in 100 ml of product.

136. Percentage volume in volume (% v/v):  It expresses the number of milliliters of solute in 100 ml of product.

137. Percentage volume in weight (% v/w): It expresses the number of millilitres of solute in 100 g of product.

138. Parts per million (ppm): “Parts per Million” is a way to quantify very low concentrations of substances. For example, 1 ppm is equivalent to 1 milligram of solute per litre of liquid (abbreviated as mg/L). 1 milligram of solute per millilitre of liquid (abbreviated as mg/ml).

            1 mg/ml = 1000 ppm

139. Cleaning Validation: A methodology used to assure effectiveness and consistency of cleaning process to remove residue and contaminates.

140. Type A Cleaning: It is dry cleaning process performed between the same type of products or campaign batches generally called as batch to batch changeover. This type of cleaning   consists of removal of drug powders from the surface with the help of clean cloth or     scraper/scrubber.

141. Type B Cleaning: It is wet cleaning process in which cleaning solution is used for cleaning of Equipment during product to product changeover.This type of cleaning   consists of total removal of drug residue from the surface with the help of cleaning agent and purified water to avoid previous product residue (contamination) in next product.

142. Rinse Sampling: It is the method by which all the contact surface of the cleaned equipment is rinsed with specified amount of water then collecting certain volume of the rinse water into a vial for analysis.

143. Swab Sampling:This method involves wiping a predetermined area of the cleaned equipment with a swab that has been moistened with a solvent determined by the contaminating compound. Usually the surface is wiped with one side of the cotton swab using a certain number of strokes, then the swab is flipped and wiped with other side of the cotton swab.

144. Flammable Chemicals: A flammable material can be a solid, liquid or gas. It is defined as any liquid having a flash point below 100^o F (37.8^oC). Example: Benzene, Methanol and Ethanol.

145. Flash Point: It is defined as the lowest temperature at which a liquid can form an ignitable mixture in air near the surface of the liquid. The lower the flash point, the easier it is to ignite the material.

146. Retest Period: Retest Period is the period of time during which the Raw Materials and Packing Materials can be considered to remain within specifications, and therefore acceptable for use in the manufacture of a given drug product, provided that it has been stored under defined conditions.

147. Expiry Date: The date at which a product is no longer potent or of therapeutic value, determined by The date for a drug estimated for its shelf life with proper storage in sealed containers away from harmful and variable factors like heat and humidity.

148. Sterilization: Sterilization is a term referring to a process that eliminates or kills all forms of life, including transmissible agents (such as fungi, bacteria, viruses, spore forms, etc.)

149. What are the types of Volumetric Titration?

 

150. Normal Phase:- In chromatography/HPLC uses a polar stationary phase and a non-polar mobile phase.

151. Reversed Phase:- In chromatography/HPLC uses a non-polar stationary phase and a polar mobile phase.

152. What are the 4 principles of chromatography?

159. What is Specific Gravity/ Relative Density?

The ratio of a substance’s density to the density of a reference substance (Water).

159. What is Weight per milliliter (wt/ml)?

Weight per milliliter (wt/ml) is a measure of density with units like grams per milliliter (𝑔/𝑚𝑙). Wt/ml tells absolute weight of particular volume.

160. What is the basic principle of KF?

The core of the method is the reaction where water (𝐻2𝑂) reacts with iodine (𝐼2) and sulfur dioxide (𝑆𝑂2) to form sulfuric acid (𝐻2𝑆𝑂4) and hydrogen iodide (𝐻𝐼). The excess iodine can be detected using a sensitive electrochemical method to mark the endpoint. It is water detection method in sample.

161. What is KF Reagent?

Karl Fischer reagent is a combination of iodine, sulfur dioxide, and water in a buffer solution (like imidazole or pyridine) and a solvent (like methanol). The overall reaction is;

162. Calculation of  water content: Plug the values from the titration into the main formula:
% Water = (Volume of KF Reagent x KF Factor x 100) /Sample     Weight (g)

163. What is Oxidation?

The loss of electrons or addition of Oxygen in substance.

e.g. C + O₂ → CO₂     (oxidation of carbon)

164. What is Reduction?

The gain of electrons or addition of Hydrogen in substance.

e.g. N₂ + 3 H₂ → 2NH₃    ( reduction of nitrogen)

165. What are mineral Acids?

Sulfuric acid (𝐻2𝑆𝑂4), Hydrochloric acid (𝐻𝐶𝑙), and Nitric acid (𝐻𝑁𝑂3). 

166. What is difference Between Organic and Inorganic Compounds?

Organic compounds always have a carbon atom, while most of the Inorganic compounds do not contain a carbon atom in them. Almost all organic compounds contain carbon-hydrogen or a simple C-H bond in them.

167. What is difference between Molecular weight and Equivalent Weight?

Molecular weight is the mass of one mole of a substance, a fixed value for a given compound.

Equivalent weight, is a variable value that depends on the substance’s role in a specific chemical reaction, calculated by dividing the molecular weight by its “n-factor” or valence. The n-factor represents the number of reactive units, such as protons or electrons, that a molecule can donate or accept.

168. Which electrode used in pH Meter?

A pH meter uses a glass electrode to measure the hydrogen ion concentration and a reference electrode (most commonly a silver-silver chloride electrode) to provide a stable, unchanging potential.

169. which solution used to store pH electrode?

A pH electrode should be stored in solution of potassium chloride (KCl), to keep the glass bulb hydrated and prevent it from drying out.

170. How to activate pH electrode?

Dip pH Electrode in a 1M Hydrochloric Acid (𝐻𝐶𝑙) solution for several hours/overnight.

171.