The Effectiveness Of Granulation Engineering Essay

The Effectiveness Of Granulation Engineering Essay

Quality by Design ( QbD ) refers to a holistic attack towards drug development. It was confirmed that the usage of multivariate methods, defined as ( QbD ) values and tools in ICH-Q8 counsel, provides an effectual agencies to carry through a greater apprehension of tablet disintegration upon stableness. ( Maltesen, 2008, Huang, 2010 )

QbD encompasses the thought of tools such as: critical quality properties ( CQAs ) ; design of experiment ( DOE ) ; hazard appraisal ; and treat analytical engineering ( PAT ) to the enlargement of pharmaceuticals. ( Verma et al, 2009, Huang, 2010 ) .The important function of PAT in a flourishing QbD environment is acknowledged, supplying an overview of of import multivariate mathematical techniques and modern analytical engineerings for procedure monitoring that facilitate procedure apprehension and finally process control. The construct of design infinite is considered, depicting the relationship between critical procedure parametric quantities ( CPPs ) and critical quality properties ( CQAs ) . The FDA ‘s Process Analytical Technology ( PAT ) proposal is anticipated to progress pharmaceutical procedure designation, simulation, and control PAT is a method for planing, analysing, and commanding fabrication throughout timely measurings ( i.e. , during treating ) of critical quality and public presentation properties of natural and in-process stuffs and procedures with the end of guaranting concluding merchandise quality.

Referee: Basu, P. , 2009

A Simple Flow Diagram ( SFD ) is as follows:

Referee: Bennett & A ; Coleman, 2003

Dry Granulation Process:

Granulation is a atom design procedure whereby little atoms are brought together to organize physically strong agglomerates. It forms granules by light compression of the pulverization blend beneath low force per unit areas. The compacts so-formed are broken up lightly to bring forth granules ( agglomerates ) . It can be used on a tablet imperativeness utilizing sloging tooling or on a axial rotation imperativeness called a roller compactor.

Purpose of each phase:

During dry granulation procedure the dry pulverizations of the active ingredient and excipients, e.g. , dry binders, disintegrants, dilutants and lubricators, are mixed in a liquidizer. The pulverization mixtures are so roller compacted and milled to organize granules. The ensuing granulation is usually blended with a lubricator and either encapsulated or compressed into a tablet. The compression of pulverization by agencies of force per unit area axial rotation can besides be accomplished by a machine called chilsonator. Unlike tablet machine, the chilsonator turns out a compacted mass in a steady uninterrupted flow. The pulverization is fed down between the rollers from the hopper which contains a coiling plumber’s snake to feed the pulverization into the compression zone. Like bullets, the sums are screened or milled for production into granules.

Ideal features of granules:

The effectivity of granulation depends on following belongingss:

Particle size of the drug and excipients

Type of binder ( strong or weak )

Volume of binder ( less or more )

Wet massing clip ( less or more )

Sum of shear applied to administer drug, binder and wet.

Drying rate ( Hydrate formation and polymorphism


It uses less equipments and infinite

For wet & A ; heat sensitive stuff

For improved decomposition as pulverization atoms are non bonded jointly by a binder.


It requires a specialised heavy responsibility tablet imperativeness to organize bullet.

It does non allow unvarying coloring material distribution as can be accomplished with wet granulation where the dye can be incorporated into binder liquid.

The procedure tends to organize more dust than wet granulation, increasing the possible taint.

Roller compression:

In instance of pharmaceutical industry, roller compression is a unit operation in the dry granulation procedure, a normally used pressure-induced agglomeration technique in which granules with acceptable flowability, compositional uniformity, compression belongingss, and chemical stableness are formed from feed stuff dwelling of mixtures of active and excipient ( inert ) pulverizations.

During roller compression, the pulverization mixture is invariably fed – frequently with the assistance of a prison guard feeder – to two counter-rotating axial rotations, which draws the pulverization between the axial rotations and compacts the pulverizations into strips or flakes of compacted stuff. The provender pulverization is densified by a combination of shear and hydrostatic emphasiss that expand from the provender emphasis, clash at the axial rotations and the confining restrictions, i.e. , axial rotations, prison guard and sidelong side seals. This procedure produces a thread, sheet or briquette, which can be milled to give the coveted granule atom size.

Active drug Excipients Roll compression Milling Tabletting

General Operational Principles:

Typical roller compression processes consist of the undermentioned stairss:

a-? Convey powdered stuff to compaction country ( usually with screw feeder ) ;

a-? Compact pulverization between two counter-rotating axial rotations with applied forces ;

a-? Mill compact ( sheet, flake or briquette ) to desired atom size distribution.

Roller compression can manage cohesive pulverizations of mutable consistence

aˆ? Aim is to heighten atom size so that pulverizations flow

aˆ? Aim to blend pulverizations to avoid segregation

Referee: americanpharmaceuticalreview.comst Point, PA, 2Roland Research Devices, Inc. , Trenton, NJ

Compaction procedure inside informations:

Slip zone

Deaeration of the pulverization occurs in this part.

Powder is enforced into the spread between the axial rotations via a skiding gesture that consequences from the rotary motion of the provender prison guard and axial rotation surfaces.

Internal clash coefficient of pulverization determines the size of the faux pas zone ( larger coefficient – smaller faux pas zone – longer compression clip ) .

Nip zone

Defined by the shot angle which is determined theoretically by the compaction factor, internal clash angle and roll/powder clash angle.

Starts where no slippage of pulverization occurs at the axial rotation surface.

Powder is carried into the axial rotation spread at the similar velocity as the axial rotation surface.

To carry through acceptable compression, the nip angle must be immense or abode clip in the nip zone must be improved to allow atom adhering to go on.

Release zone

Elastic recovery ( enlargement ) of the compacted sheet occurs as it is free from the axial rotations.

Extension of the compact is a map of physical features of the stuff, axial rotation velocity, and axial rotation diameter.

More efficient deaeration of pulverization reduces the enlargement due to superior bond formation ( transition to fictile distortion as opposed to elastic ) .

A successful procedure based on roller compression followed by milling should bring forth a granule with consistent atom size distribution, denseness, and porousness control.

Roller Compaction: Advantages

Binder-less agglomeration

Dry – therefore suited for wet and heat-sensitive stuffs can be processed

Simple procedure ( no wetting or drying stairss )

Continuous procedure

Readily scale able: Everything linear.

Decreases unacceptable elastic recovery

Amenable to Chuck

Drug and colour migration do non happen

Shorter decomposition times can be obtained ( if no binder is used )

Less equipment, cost, and infinite are required

Reasons to utilize Roller Compaction:

No or low dust, increased safety when working with toxic or explosive stuffs

Improved flow features

No segregation of constituents ; increased majority denseness

Increased atom size

Equipment variables:

Rolls mounted horizontally, vertically or inclined

Roll diameter

Roll breadth

Feeding system:

Gravity vs. screw feeder

Powder de-aeration unit

Two fixed axial rotations vs. one fixed and one movable roller

Critical Procedure Parameters:

Roll Compaction pressure/specific compression force ( i.e. compression force per centimeter of axial rotation breadth )

Speed of feeding prison guards ( perpendicular vs. horizontal ) or Feed screw rate ( velocity )

Roll velocity

Roll Gap/ Separation

Milling Conditions ( i.e. room temperature and humidness )

CPP can be efficient in footings of volume in and volume out.

Referee: Mansa et al. , 2008

Impact of critical procedure parametric quantities:

Even with suited roller compactor and parts, roller compression procedure parametric quantities have really considerable effects on procedure feasibleness, granule tablet ability and thread quality. Compaction force, roll velocity, and feeder prison guards velocity are the critical parametric quantities needed to be optimized to better merchandise quality.

Roll velocity

Faster roll velocity agencies faster throughput — Normally rollers have feedback cringle to feeders

Fictile stuffs will deform more the slower the axial rotation velocity

Impact of altering axial rotation velocity on compaction dependant on stuff belongingss of provender stock.

Brittle stuffs less disposed to be exaggerated by slower axial rotation velocity, but rollers are gettable so easy that strain rate effects by and large do non happen.

It controls the dwell clip of the compact and finally the throughput of the roller compactor.

The choice of axial rotation velocity depends on the flowability, snap, and malleability of the pulverization.

Referee: Gupta et Al, 2003

Screw velocity

For equipment with force eating, screw velocity is a of import procedure parametric quantity to accomplish high granule quality.

The force produced by a revolving flight generates a downward compaction force that non merely forces the pulverization into the compression zone but besides pre-densifies the pulverization.

Compaction force

A lowest compression force is needed to compact the loose pulverization into threads.

As described earlier, under force per unit area, solid atoms densify, deform or fracture, and bond to organize threads.

At a higher compression force, stronger compact with a lower porousness and less all right is produced. ( Pitt, K. , 2009 )

Critical to Quality Attributes:

Ribbon Density, strength and thickness caused due to turn over force/pressure

Ribbon/particle size and form caused by axial rotation gap/separation

Appearance caused due to turn over velocity

Change in porousness caused due to add-on of binders

Granule denseness and granule porousness

Particle size distribution

Ribbon porousness

Referee: Mansa et al. , 2008

Particle size, zeta possible and the physical signifier of the drug constituted the critical quality properties ( CQAs ) .ck & A ; Co. , I

Procedure control:

Normally merely 2 out of the 3 parametric quantities of axial rotation force per unit area axial rotation spread and feed-rate can be set in any control cringle.

There are 3 governable parametric quantities: axial rotation force per unit area, axial rotation spread ( or, when without spread control, thread thickness that can be controlled by provender prison guards velocity ) , and roll velocity.

3rd variable will so drift to run into the other 2 set parametric quantities.

E.g. if set spread of 2mm and put force per unit area of 40MPa, so screw feed rate will be varied by control cringle.

Roller Compaction: Disadvantages

Potential for high sum of re-cycle or reprocessing

Possible loss of tablet squeezability

Restrictions in coloring material assortment

Dissolution can be adversely affected, due to densification

Powders must be compressible ( if primary merchandise pulverization is non compressible, so a compressible constituent should be added to the preparation ) , typically requires the add-on of a lubricator to take down lodging to the axial rotations.

Roller compression: Rationalization

Densification = Volume in/volume out

The greater volume alteration, the greater the compaction

Mass in and out remains changeless in a unit clip

Hence Density ( or Solid Fraction ) is cardinal factor being changed ( Solid fraction = Envelope Density ?True Density )

Solid Fraction during Roller Compaction:

Referee: Teng et al. , 2009

Dry Binders

One of import requirement for a dry binder is good pulverization flowability. The dry binding character are prejudiced by pulverization ‘s morphology, form and size, malleability, porousness, squeezability, hygroscopicity, wet & A ; heat, stableness to air, and compatibility with APIs.

Adhering agents are often incorporated into dry granulation preparations to improvize granule and tablet strength. Tablet adhering agents added during dry granulation techniques are called ‘pressure binders. The stronger binding singularity are governed by intermolecular forces and mechanical engagement, depending upon the excipients type. The function of binders is to agglomerate drug substance and excipients to organize improved granules with suited denseness, atom size distribution, strength, & A ; therefore tablets with tolerable crumbliness. At low binder degrees, there are non adequate binders to cover atom surfaces. Consequently, even though threads may be formed after roller compression, the strength and atom size control of granules can be really hapless. On the other manus, if the binder degree is excessively high, tablet decomposition and disintegration may endure. Smaller binder atoms with a larger surface country give better surface coverage of other ingredients, therefore heighten the binder efficiency, e.g. cellulose and amylum derived functions, PVP, etc. Many cellulose and starch derived functions have been used as binders in roller compression. These binders include methylcellulose, ethylcellulose, hypromellose ( hydroxypropyl methylcellulose ) , HPC ( hydroxypropylcellulose ) , pregelatinized maize amylum, and MCC ( microcrystalline cellulose ) . ( Teng et al.,2009 )


The primary map of fillers is to ease preparation design and procedure development. Fillers play a critical function in modifying the pre-compaction blend belongingss to carry through desirable compatibility, flow, and denseness. For a really fictile or brickle drug substance, the pick of filler may be the most important measure in preparation design. By equilibrating the plasticity/elasticity/brittleness of the pre-compaction pulverization, fillers are important in doing roller compaction procedure executable and in guaranting good thread and granule quality.

Excipient/granule atom size

Normally, all right atoms show enhanced compatibility than harsh atoms. The effects of atom size on compression belongingss are more outstanding for plastic stuffs than for brickle stuffs. This consequence can be best explained by atom adhering theory. Excipients play a major function in the development of robust preparations because they can act upon the grade of granule compaction and binding and can besides absorb mechanical emphasis derived from the granulation and tableting procedures without impacting tablet hardness and tensile strength.


They are added to a great figure of roller compression preparations to develop the flow ability of pre-compression pulverization. They act as ball bearings to diminish the clash among atoms.


Its map is to decrease the clash between reaching equipment surface and granule/tablets. Lubrication is correspondent to surfacing procedure. Lubricants can organize thin movies on atom surfaces, therefore modifying the interaction between solid majorities and reaching equipment surface. Intragranularly, lubricants cut down the clash between thread and axial rotations, whereas extra granularly, lubricators decrease the clash between tablets and decease walls.


A disintegrant is used to interrupt tablets into granules and farther into all right atoms, and to accomplish satisfactory decomposition clip and disintegration rate. Thus, proper control of thread and granule porousness can take to improved decomposition efficiency. Here, disintegrants can be used in both intragranular and extragranular parts. ( Teng et al.,2009 )

Referee: Basu, P. , 2009

Design Space:


Roller compression [ dry granulation ] has gained popularity throughout the pharmaceutical industry. One end of roller compression is to better squeezability and output quotable tablet disintegration and content uniformity. To guarantee downstream procedure and merchandise consistence, a successful roller compression procedure establishes a uninterrupted flow with a consistent atom size distribution. However, incompatibilities frequently occur during dry granulation graduated table up due to altering natural stuffs or procedure kineticss such as segregation, compression force, and flow belongingss. The application of FBRMA® , unmoved atom word picture, is demonstrated to map the design infinite and optimise a series of roller compression tallies while changing natural stuffs, flow rates, and roller compression forces. FBRMA® allows a user to straight associate procedure control parametric quantities to the atom distribution and the merchandise public presentation. By planing a robust roller compression process one can guarantee consistent downstream processing from dry granulation through tablet compaction.

METTLER TOLEDO C35 FBRM investigation proctors roller compression in existent clip

Referee: hypertext transfer protocol: //


Roller compactor experiments were run with several natural stuffs while changing the roller compression force, flow rate, and rotor velocity. The procedure repeatability was characterized with unmoved FBRMA® engineering and offline analysis.

Referee: Singh et Al, 2009

Referee: Chi-wan Chen, 2006


The influence of altering roller compression force, flow rate, and rotor velocity were quantified utilizing existent clip unmoved FBRMA® atom word picture. Compaction force and flow rate have a important influence on the downstream atom distribution. Rotor velocity had less consequence on the atom distribution. A good correlativity was obtained between the unmoved FBRMA® and downstream procedure efficiency and merchandise quality.

Referee: Lepore.J, Spavins.J, J Pharm Innov ( 2008 ) 3:79-87


Roller compression is a complex procedure with viing mechanisms of breakage and agglomeration. Using unmoved PAT for atom word picture, it is possible to quantify the consequence of critical procedure parametric quantities such as roller compression force and flow rate. By qualifying these effects one can utilize FBRMA® to optimise and command graduated table up procedure parametric quantities to keep compaction consistence and merchandise public presentation. ( Burke et al. , 2010 )

Bibliography Reference

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Burke, G. , Pandey, A. , O’Grady, D. , Dycus, B. & A ; Smith, B. ( 2010 ) , Roller Compaction Processes Optimization utilizing FBRMA® In-Situ Particle Characterization. Available from: Patheon Pharmaceuticals Inc. & A ; Mettler Toledo, Web site: hypertext transfer protocol: // [ Accessed: February 2, 2011 ] .