Top granulation interview questions and answers

Granulation interview questions and answers : granulation department is core department in production manufacturing area. granulation process improve the power properties and make more suitable blend for compression stage.

granulation interview questions and answers

Following are the top granulation interview questions and answers. These are highly recommended interview questions must be go through for better performance in production interview.

What is the granulation ?

In the pharmaceutical industry, granulation refers to the process of forming granules from fine powers particles with help of binder mainly in RMG. Granules are aggregates or agglomeration of fine powder particles.

The powder morphology is modified through the use of either a liquid that causes particles to bind through capillary forces or dry compaction forces.

Why granulation process is important ?

Granulation is an important step in the production of various pharmaceutical dosage forms, such as tablets and capsules because:

• Granulation process Enhanced flow properties of power
• Granulation process Increased compressibility of power
• Granulation process improves Blend uniformity specially of potent drug by provides more homogeneous mixing of blend.
• Granulation process can reduce compressed tablets defects like capping, lamination and sticking.
• Alteration of physical appearance to more spherical, uniform, or larger particles
• Enhanced hydrophilic surface properties
• Uniform distribution of all formulation ingredients.

What are the type of the granulation process?

There are mainly 5 types of granulation:

• Wet granulation
• Dry granualtion
• Spray Dry granulation
• Hot melt granulation
• Extrusion and spheronization process

How to determine end point of granulation ?

The endpoint of granulation in pharmaceutical manufacturing typically refers to the desired characteristics granules. it ensure that the granules are suitable for further processing.

The endpoint of granulation mainly determine by :

• Visual observation method
• Banana breaking test or Hand squeeze test
• Measurements of power consumption of the mixer motor
• Impeller Torque

What is full form of RMG in pharma ?

RMG is abbreviation of Rapid mixture granulator (RMG) used in granulation process in the pharmaceutical industry.

What is the working capacity of RMG ?

A useful working capacity of up to 70% to 30% of the bowl volume.

What is the Banana breaking method or Hand squeeze test for determination of granulation end point ?

One of the simple, old and most commonly used method for detecting endpoint is Banana breaking method : Wear hand gloves, take one handful of wet granules in hand and close the fist and wet mass is squeezed in hand to make a lump. the resulting lump looks like banana. then break it throughout the thumb, lump of wet mass (banana) should be break into two or three smaller lump only there should be no dry powder or fine powder.

This method depends on operators skills and can not be validated.

what is working principle of Rapid mixture granulator (RMG) ?

Rapid mixture granulator works on agitation and tumbling. The impeller is responsible for uniformly mixing wet granules and making agglomeration of fine particles into larger granules and the chopper helps in breaking the extra large agglomeration or reducing particle size.

What is the rpm of RMG?

• Impellers
  • Impeller Slow speed is 37 RPM.
  • Impeller Fast speed is 74 RPM.
• Chopper :
  • Chopper slow speed is 1440 RPM.
  • Chopper fast speed is 2880 RPM.

What are the parts of RMG?

Rapid mixture granulator components like :

• Mixing chamber
• Impeller
• Chopper
• Discharge port
• vent air filter
• Pursuing air system
• Port provided for solution inlet with spraying assembly
• Impeller motor
• Chopper motor

What is the speed of impeller in RMG?

• Impeller Slow speed is 37 RPM.
• Impeller Fast speed is 74 RPM.

How do you calculate occupancy of RMG?

Calculation for RMG of 500 Lit capacity with 0.5 gm/ml bulk density power is as follows:

• 30% occupancy of equipment: 500 Lit × 0.3 × 0.5 gm/ml= 75 kg.
• 70% occupancy of equipment: 500 Lit × 0.7 × 0.5 gm/ml= 175 kg.
• 100% occupancy of equipment: 500 Lit × 1 × 0.5 gm/ml= 250 kg.

What are the US Mesh size and corresponding size in micron, mm and inch for sieves ?

Mesh size	Microns	Inches	mm
10 #	2000	0.0787	2
20 #	840	0.0311	0.841
25 #	707	0.028	0.707
30 #	595	0.0232	0.595
35 #	500	0.0197	0.5
40 #	400	0.0165	0.4
45 #	354	0.0138	0.354
50 #	297	0.0117	0.297
60 #	250	0.0098	0.25
70 #	210	0.0083	0.21
80 #	177	0.007	0.177
100 #	149	0.0059	0.149

[granulation interview questions and answers]

What is the aperture size of the screen?

The size of a square opening (length of clear space between individual wires) is called the aperture size of the screen.

What is the Mesh number of screens?

Mesh number of screens is defined as the number of aperture or opening per linear inch of the screen. E.g. A screen having 10 square openings per inch is said to have Mesh no. 10. Higher the mesh number, smaller the aperture size of the screen.

What are the equipment used during the Wet Granulation Process?

Following equipment are used during the Wet Granulation Process.

• Vibratory sifter
• High Shear mixer/ granulator OR Rapid Mixture granulator (RMG)
• Fluid Bed Dryer (FBD)
• Fluid Bed processer (FBP)
• Cutting mills such as Multi mill, Co-mill, Hammer mill etc.
• Extruders and Spheronizer

What are the equipment used during the Dry Granulation Process?

Following equipment are used during the Dry Granulation Process.

• Roller Compactor
• Granulator
• Vibratory sifter
• Cutting mills such as Multi mill, Co-mill, Hammer mill etc.

What is the most commonly used testing method to determine powder flow?

There are four commonly used methods for testing powder flow:

• Angle of repose
• Compressibility index
• Hausner ratio
• Flow rate through an orifice
• Shear cell

What is Angle of Repose?

Definition of Angle of Repose: The angle of repose is a relatively simple technique for estimating the flow properties of a powder. It is determined by allowing a powder to flow through a funnel and fall freely onto a fixed diameter base. The height and diameter of the resulting cone are measured.

What is the Compressibility index ?

The Compressibility Index (Carr Compressibility Index) is a measure of the tendency of a powder to be compressed. It is a measure of the powder’s ability to settle, and it permits an assessment of the relative importance of inter-particulate interactions.

What is Hausner-ratio?

The Hausner-ratio is measures that can be used to predict the tendency of a given powder sample to be compressed. Hausner-Ratio reflects the importance of inter-particulate interactions.

What are the characteristic of Finger Bags used for Fluid Bed Dryer (FBD) or Fluid Bed Processor (FBP)?

• Antistatic
• Waterproof cloth
• Able to handle granulation of highly viscous materials, such as extract powder
• Non-stick cloth bag
• Good permeability
• Good boiling effect
• Cost-efficient and durable

What is the material of construction (MOC) of Finger Bags used for Fluid Bed Dryer (FBD) or Fluid Bed Processor (FBP) ?

Finger bags are constructed by a combination of Antistatic polymer, Nylon fabric and Cotton fabric. Following materials are also used for Finger bags’ construction.

• Antistatic
• Epitropic
• Polypropylene
• Polyester
• Stain

What are the typically seen micron ratings of Finger Bags used for Fluid Bed Dryer (FBD) or Fluid Bed Processor (FBP) ?

Micron Rating: 1, 5, 10, 15, 25, 50, 100

Explain parts of Fluid bed dryer and Fluid bed processor?

Following are the parts of Fluid bed dryer and Fluid bed equipment

• Plenum
• Product Container
• PU wheel trolley
• Inflatable gasket
• Sample collection port in Product Container
• Expansion chamber
• Finger bag
• Finger bag shaking assembly
• Inflatable gasket to seal finger bag assembly
• Broken Bag Detector (BBD) sensor OR Solid Flow Monitor (SFM) sensor
• Exhaust blower
• Exhaust filters (10 and 3 μm porosity)
• Inlet Air Handling Unit
• WIP system for cleaning
• Differential pressure sensors, across filters, across finger bag, across product container
• Spraying system (for top spray granulation)
• Product temperature sensor
• Inlet air temperature and RH sensor
• Exhaust air temperature
• CFM or Air flow sensor

Explain parts of multi-mill?

• Material Charging Hopper: To load the material to be milled
• Milling chamber: Milling of material happens within the chamber with the help of Cutting blades and desired size of particles are passed through specific size screen
• Discharge port: Milled material is discharged from this part
• Castor wheels: To move the mill from one place to another place
• Operating Panel: To operate the equipment
• Screen: To produce desired particle size
• Cutting blades: To mill the material

What is the Material Of Construction (MOC) of multi-mill parts?

• Product contact parts are made up of SS 316 or SS316L
• Non-product contact parts are made up of SS 304.
• Castor wheels are made up of Polyurethane.

What is the mechanism of size reduction when using multi-mill?

• Impact Milling: Particles are reduced in size by high-speed mechanical impact or impact with other particles; also known as milling, pulverizing, or comminuting.
• Cutting: Particles are reduced in size by mechanical shearing.
• Screening: Particles are reduced in size by mechanically induced attrition through a screen. This process commonly is referred to as milling or deagglomeration.

What are the typical speeds of multi-mill?

Fast speed: 2880
Medium fast speed: 2160
Medium speed: 1440
Low speed: 720

Note: Nowadays multi-mill are available with variable frequency drive where speed can be set as per the requirement (Custom speed) [granulation interview questions and answers].

What are the typical settings for milling operation using multi-mill?

Blade direction: Impact forward or Knife forward

Machine speed: Using V belt adjustment or using VFD as per machine design

What is Vibro sifter?

Vibro-sifter is equipment used for separating particles based upon particle size alone and without any significant particle size reduction. This process commonly is referred to as screening or bolting. Vibration and Gyratory motion plays an important role to facilitate the screening process.

What is the principle of Vibro sifter?

Vibro-sifters work on the principle of separation. Particles are segregated based upon particle size alone and without any significant particle size reduction. This process commonly is referred to as screening or bolting. Vibration and Gyratory motion plays an important role to facilitate the screening process.

The mechanism on which Vibro-Sifter works is the principle of gyratory vibrations. The material is separated based on its particle size. Once the motor gets energized, vibration is caused in the screen/. This makes material travel across the sieves according to its particle size and sieve/ screen size.

what are the subclasses of Sifter as per SUPAC ?

Separator subclasses as per SUPAC : Vibratory/ Shaker and Centrifugal.

What is the gyratory motion of a vibro sifter and how does it get generated?

In the vibro sifter gyratory motion is obtained from a specially designed gyro motor, which is fitted underneath the vibrating assembly. A specially designed rugged spring completely isolates this assembly from the base with the help of Gyro-motor.

The motor is fitted with eccentric weights present at its top as well as base to create centrifugal force. This whole assembly is covered by an SS plate [granulation interview questions and answers].

What are different parts of vibro sifter?

• Dust cover
• Clamp for assembling of different parts
• Inlet
• Sieve/ screen
• Vibrating motor for Gyratory motion with eccentrically arranged top and bottom hammer
• Caster wheel
• Discharge port
• Spring

How to discharge the static electricity which may get generated over the vibro sifter sieve when silicone bonded sieve is used?

Following are the solutions to discharge the static electricity which may get generated over the vibro sifter sieve when silicone bonded screen is used:

• Using antistatic screen
• Use C clamp over the silicone bonded sieve which makes the entire assembly conductive and to provide earthing to the body of the equipment.

What is a solution preparation vessel?

The solution preparation vessel is a closed tank used to prepare solution at room temperature or elevated temperature by using electrical heating or steam heating. To mix the solution homogeneously, it consists of stirring to create a vortex inside the solution [granulation interview questions and answers].

What is the use of solution preparation vessels in the pharmaceutical industry?

The solution preparation vessel is used to prepare various types of solutions such as binder solution, coating solution, heating of water, liquid preparations such as syrup, suspension, solutions, etc. The vessel is used to ensure a homogeneous mix.

Explain parts of solution preparation vessel and Material of Construction (MOC)?

• Solution preparation Tank – SS316 or SS 316 L
• Stirrer – SS316 or SS 316 L
• Variable Frequency Drive
• Pressure gauge for jacket
• Discharge valve (Zero dead leg and sanitary type, Ball valve is not acceptable) – SS316 or SS316L
• Caster wheel for movement – Polyurethane

What is vortex and how is it helpful for solution preparation?

A circular, spiral, or helical motion in a fluid. A vortex often forms around areas of low pressure and attracts the fluid (and the objects moving within it) toward its center.
Velocity in the vortex is maximum next to the axis and inversely decreases with the radius.
Vortex enhances the desired solubility of pharmaceutical binder solute into the various solvents.

What should be characteristics of the solution preparation vessel ?

• Zero dead leg and sanitary design components
• Stationary or mobile use
• Capable to handle wide temperature range (design as per requirement)
• The Internal surfaces of our preparation vessels are flush ground and mirror polished to <0.3 Microns Ra and electro-polished
• Easy to clean
• Adjustable speed of stirrer
• Adjustable temperature
• 21 CFR Part 11 compliant and EU Annex 11 Compliant
• Low maintenance and long service

What are the different particle size reduction mechanisms?

Particle size reduction mechanisms	Description
Impact	Particle size reduction by applying an instantaneous force perpendicular to the particle/ agglomerate surface. The force can result from particle-to-particle or particle-to-mill surface collision.
Attrition	Particle size reduction by applying a force in a direction parallel to the particle surface.
Compression	Particle size reduction by applying a force slowly (as compared to Impact) to the particle surface in a direction toward the center of the particle.
Cutting	Particle size reduction by applying a shearing force to a material.

Explain Equipment Classifications for Particle Size Reduction ?

Following are the Classifications for Particle Size Reduction Equipment

1. Impact Mills: Impact Mills or Communiting Mill for solid milling with Swivel Knives or Blades. E.g. Hammer mill, Communiting Mill – Cizer-mill
2. Cutting Mills: Although cutting mills may differ from one another in whether the knives are movable or fixed. E.g. Multi-mill, Co-mill
3. Screening Mills : Rotating Impeller Rotating Screen Oscillating Bar. E.g. Multi-mill, Co-mill
4. Screening Mills: Rotating Impeller Rotating Screen Oscillating Bar. E.g. Oscillating granulator
5. Tumbling Mills: Tumbling mill used the grinding media like Ball Media Rod Media with Vibrating. E.g. Ball mill, Tubular Rod Mills
6. Separators: Separator used to induce particle movement. Vibratory/ Shaker Centrifugal. E.g. Vibro sifter, Ultra Centrifugal Mill

Equipment type	Description	Example
Impact Mills	Impact Mills or Communiting Mill for solid milling with Swivel Knives or Blades	E.g. Hammer mill, Communiting Mill – Cizer-mill
Cutting Mills	Although cutting mills may differ from one another in whether the knives are movable or fixed	E.g. Multi-mill, Co-mill
Screening Mills	Rotating Impeller Rotating Screen Oscillating Bar	E.g. Oscillating granulator
Tumbling Mills	Tumbling mill used the grinding media like Ball Media Rod Media with Vibrating	E.g. Ball mill, Tubular Rod Mills
Separators	Separator used to induce particle movement. Vibratory/ Shaker Centrifugal	E.g. Vibro-sifter, Ultra Centrifugal Mill

What is Blending and Mixing?

Mixing and Blending involves the changing the orientation of particles with respect to one another to create uniformity.

What is the Operating Principles of Blender?

The Operating Principles of Blender is diffusion The particles are rotated with respect to each other when moved in random order and friction between them is lessened due to the bed expanding (usually inside a rotating container).

What is Drying?

The process of removing liquids from a solid via the process of evaporation.

What is the Operating Principles of FBD?

Direct Heating and Fluidized Solids Bed Transfer of heat occurs through direct contact between wet solids and hot gasses. The liquid that has vaporized gets carried off by drying gases. The solids are expanding with the particles being supported by drag forces generated through the gas phases. The gas and solids interact and behave as the boiling liquid. This is often known as dry-up of the fluid bed.

What is the Operating Principles of Spray Drying ?

Direct Heating, Dilute Solids Bed, Spray Drying : Transfer of heat can be accomplished through the direct interaction between dispersed liquid as well as hot gases. The liquid that is fed to the system could be a slurry, solution or emulsion, gel, or paste, as long it can be pumped and able of being atomized. The liquid is dispersed in tiny droplets in a gas stream that is hot in which they quickly evaporate before they reach the walls in the chamber for drying. The liquid that has evaporated gets carried off by drying gases. The solids expand completely and separated so that they have no impact on one another.

What is the Operating Principles of Tray Drying ?

Direct Heating, Static Solids Bed : The transfer of heat occurs through direct contact between wet solids as well as hot gases. The liquid that is vaporized is then carried away by drying gases. There isn’t any relative motion between solid particles. The solids bed is an extremely dense bed with particles resting on each other.

What is the Operating Principles of freeze Drying ?

Indirect Conduction, Lyophilization.

What are the Critical Process Parameters (CPP) and Critical Quality Attributes (CQA) of granulation ?

The Critical Process Parameters (CPP) of granulation process are binder preparation time, binder preparation speed, binder solution or water amount, Dry Mixing time, Wet Mixing time, Impeller speed, Chopper speed and Ampere load.

The Critical Quality Attributes (CQA) of granulation process are particle size distribution (PSD), LOD and blend uniformity.

Unit Operations	Critical Process Parameters	Critical Quality Attributes
Binder preparation	Mixing time (Stirrer time)	Viscosity of Binder solution
	Mixing speed (Stirrer Speed)	Viscosity of Binder solution
	Binder solution or water amount	Hardness, Friability, Dissolution
Wet Granulation	Binder solution addition rate	Hardness, Friability, Dissolution
	Dry Mixing time	Blend uniformity (BU)
	Wet Mixing time	Hardness, Friability, Dissolution, PSD
	Impeller speed	Hardness, Friability, Dissolution, PSD
	Chopper speed	Hardness, Friability, Dissolution, PSD
	Ampere load	Hardness, Friability, Dissolution

What are the Critical Process Parameters (CPP) and Critical Quality Attributes (CQA) of Fluid bed drying ?

The Critical Process Parameters (CPP) of Fluid bed drying process are Inlet air temperature, Outlet air temperature or Exhaust air temperature, Inlet air flow (CFM) and drying time.

The Critical Quality Attributes (CQA) of Fluid bed drying process are particle size distribution (PSD), LOD, moisture content, RI.

Unit Operations	Critical Process Parameters	Critical Quality Attributes
Fluid bed drying	Inlet air flow (CFM)	PSD, LOD
	Dew point	LOD, moisture content
	Drying Time	LOD, moisture content
	Inlet air temperature	LOD, moisture content, RI
	Exhaust air temperature	LOD, moisture content

What are the Critical Process Parameters (CPP) and Critical Quality Attributes (CQA) of Blending/Lubrication?

The Critical Process Parameters (CPP) of Blending/Lubrication process are Blending time and RPM of blender.

The Critical Quality Attributes (CQA) of Blending/Lubrication are blend uniformity (BU) and Assay.

Unit Operations	Critical Process Parameters	Critical Quality Attributes
Blending/Lubrication	RPM of blender	BU, Assay
	Blending time	BU, Assay

How to perform calibration of Moisture Analysis?

• Add 2.0 gm Di-Sodium Tartrate in pan and start test.
• Acceptance Criteria: % Moisture content of Di-Sodium Tartrate sample should be 15 – 16 %.

Granulation interview questions and answers pdf

Granulation interview questions and answers pdf

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