Air suspension atom coating is a procedure by which thin coatings are applied to pulverize atoms. The coatings can be formulated to move as permeable barriers to increase pulverization shelf life or to leave controlled release character.
The production of functional seeds with good physical features depends on the belongingss of the stuffs used and the success of the procedure can be classified as preparation dependant.
Wurster fluid bed movie coating is a dynamic procedure that is influenced as much by application conditions as it is by the stuffs used in the procedure. Drying capacity is inherently a cardinal concern of the procedure and is influenced by atomisation belongingss, dissolver volatility, air flow and solvent/solid interaction.
With the cognition of influence of procedure parametric quantities on the coating public presentation factors, the surfacing procedure in Wurster coating was better understood. It is anticipated that this successfully developed functional coating seeds by air suspension coating can be optimized for choice terminal merchandises.
The Wurster processing insert, patented by Glatt in 1992, provides important betterments over conventional Wurster coating engineerings through increased productiveness, high spray rates, increased outputs and applications with all right atoms.
Wurster fluid bed movie coating of particulate stuffs involves insistent ( cyclic ) motion of nucleus atoms through an atomized spray part in a comparatively controlled mode. Each rhythm of the motion involves wetting followed by drying and it is a balance of this rhythm that provides the appropriate quality and consistence in the merchandise for the critical merchandise parametric quantities. Because this balance involves many critical parametric quantities it is disputing to foretell where the balance lies. Nevertheless, an apprehension of the parameter relationships provides a prognostic tool for filmcoating procedures. In this work, filmcoating procedures were looked at from an application position to leave application guidelines. Included in this rating are drying capacity factors such as atomization/droplet size, dissolver volatility, air flow, and solvent/solid interactions affecting both nucleus and coating stuffs. The influences of filmcoat and nucleus stuff belongingss are besides considered. Findingss and decisions are supported by procedure observations and concluding merchandise public presentation.
History and Chronological Literature ReviewA of Fluidized Bed Systems
HistoryA ( 1, 2 )
Scattered survey to early observations of what is known today is fluidization can be found in published literature as far back on 1878. ( Swarbrick J, Boylan J.C, “ Fluid bed drier, granulator and coaters, A Encyclopedia of pharmaceutical technologyA , Marcel Dekker INC, New York, Volume- 6,171-173, 1992 )
InA 1940sA the fluidized solid procedure was commercialized on a monolithic graduated table in the crude oil industry to consequence adumbrate contact between the accelerator and hot bluess in the snap of heavy hydrocarbons to fuel oil.
The construct of fluidized solids really arose in the field of catalytic snap procedure. The standard oil development company has a batch of part in the field of fluidization thenA Prof. W.K Lewis and E.R GillilandA carried out independent research on flow belongingss of powdery solids suspended in gases and developed the construct of fluid bedA . ( Othomer D.F, ” Background, History and Future of Fluid bed systems ” , A FluidizationA , Reinhold publication corporation, New York, 102-115,1956 ) .A The first commercial works utilizing the fluid solids technique rule was put into operation in the yearA 1930A for nonpharmaceutical application but the procedure was foremost used for pharmaceutical application in the twelvemonth 1960 byA Wurster. The coating of tablets by spraying the surfacing solution into a bed of tablets suspended in a watercourse of warm air was invented byA Dale Wursterwhose first patent for the method was filed inA 1953A .A Granulation of pulverization in a fluidized bed carried out inA 1960A byA WursterA . Then theA 1980sA have seen anA detonation in the research, application and commercialisation of fluid bed procedure. ( Swarbrick )
2. Concept Of FluidizationA ( Swarbrick ) ( Banks, Michael, Aulton, Michael E, “ Fluidized bed granulation – A ChronologyA ” A , A Drug development and industrial pharmacyA , , 17 ( 11 ) , 1437-1463, 1991 ) ( Ylirussi J. , Rasanen E, Rantanen J. , Mannermaa J.P “ The word picture of Fluidization Behavior Using a Novel Multichamber Microscale Fluid Bed ” , A Journal of Pharmaceutical SciencesA , , 93 ( 3 ) , 780-791,2004 )
2.1. Introduction ( Vazquez.E.R, “ Optimization of drying terminal point measuring for the mechanization of Fluidized bed dryer utilizing FT-IR Spectroscopy ” A M.ScA ThesisA , , University of Puerto Rico, Mayaguez Campus, 17, 2004, ( Lachman L, Lieberman H.A, Kanig J.L, Third edition “ Granulation ” , A The Theory and pattern of industrial pharmaceutics, VergheseA Publishing House, Bombay, 58-59, 1991 ) , ( www.engr.pitt.edu/chemical/undergrad/lab-manuals ) )
Many of import industrial procedures rely upon intimate contact between a fluid ( liquid or gas ) and a farinaceous stuff. ( 8 ) A In early applications, the fluid flowed through a inactive bed of granules supported on a grid. provided the stuff is suited, great betterment in commixture and contact is achieved if the granule size is decently matched to the upward speed of the fluid. The atoms of stuff will be supported by the retarding force forces and the bed is said to beA ” fluidized ” .A A The fluidized beds show following liquid or fluid like propertiesA ( 7, 9 )
Lighter objects float on top of the bedA ( i.e. , A objects less dense than the bulk denseness of the bed ) ,
The surface stays horizontal even in atilt beds,
The solids can flux through an gap in the vas merely like a liquid,
The beds have a “ inactive ” force per unit area caput due to gravitation.
Degrees between two similar fluidized beds equalise their inactive force per unit area caputs.
It has a zero angle of repose.A ( 7 )
Assumes the form of vas that contains it.A ( 7 )
A gas-fluidized bed may hold the visual aspect of a boiling liquid. It has bubbles, which rise and look to split. The bubbles result in vigorous commixture and a by and large horizontal free surfaceA . ( 8 ) A The gesture of the bed varies with the fluid flow rate. At high speeds, atoms may go entrained and transported by the fluid. ( 4 )
Fluidization depends upon-
Speed of air
2.2 Principle Of FluidizationA Vazquez
The rule of operation of fluidized systems are based on the fact that if a gas is allowed to flux through a bed of particulate solids at speed greater than the settling speed of the atoms and less than the terminal speed for pneumatic conveyance and equal to the minimal speed of fluidization ( VA mfA ) , the solids get partly suspended in the watercourse of upward traveling gas. The gas watercourse negates the gravitative pull due to weight of atoms to enable the suspended province of the solid.
The attendant mixture of solids and gas behave like a liquid and therefore justly solids are called Fluidized. The solid atoms are continually caught up in Eddies and autumn back in a random boiling gesture so that each fluidized atom is surrounded by the gas watercourse for efficient drying or granulation or surfacing purpose. In the procedure of fluidization there occurs an intense commixture between the solids or gas resulting in unvarying status of temperature, composing and atom size distribution throughout the bed.
2.3 Theory Of FluidizationA ( Lachman )
A. Batch Fluid Bed Systems
1 ) Top Spray Coating
2 ) Bottom Spray Coating ( Wurster Coating )
3 ) Tangential Spray Coating ( Rotor Pellet Coating )
B. Continuous Fluid Bed Systems
1 ) Top Spray Coating
2 ) Bottom Spray Coating
2.3.1 Phenomenon of Fluidization
Phases of fluidization: – The phases of fluidization is largely based on the fluid speed go throughing through the atom bed. Harmonizing toA RidgewayA andA QuinnA ( 1 ) A the phases of fluidization can be summarized as follows.
1 ) Inactive bed
2 ) Expanded bed
3 ) Mobile bed
4 ) Bubble formation
5 ) Pneumatic conveyance
2.3.2 Role of Fluidization velocityA ( 9 )
A mass of finely divided solids is transformed into a fluidized bed by raising action of gas passing through it. Therefore three phases can be identified in the procedure of fluidizing a bed of solids establishing on the speed of gas flow through it. They include
1 ) Fixed bed or Inactive Bed
2 ) Expanded bed or particulate fluidization.
3 ) Mobilized bed
1 ) When a fluid is pumped upward through a bed of all right solid atoms at aA really low flowA rate the fluid percolates through the nothingness infinites ( pores ) without upseting the bed. This is known as aA fixed bedprocessA . ( 9 )
2 ) If the upwardA flow rate is really largeA the bed mobilizes pneumatically and may be swept out of the procedure vas. This is known asA Mobilized bedA processA . ( 9 ) A
3 ) At anA intermediate flow rateA the bed expands. This is known as anA expandedA bedA ( 9 ) A .
4 ) After nomadic bed formation if speed is further increased the bed expands well with addition in voidage andA bubble formationA ( 1 ) A occurs.
5 ) If farther addition in speed of air occurs, finally the raising force of go throughing air blows particle out of the bed wholly taking toA Pneumatic transportA . ( 1 )
In the fixed bed the atoms are in direct contact with each other, back uping each other ‘s weight. In the expanded bed the atoms have a average free distance between atoms and the atoms are supported by the drag force of the fluid. The expanded bed has the belongingss of a fluid and is besides called a fluidized bed.
As shown in Figure below, the speed of the fluid through the bed antonym to the way of gravitation determines whether the bed is fixed, expanded, or is swept out. This led to the development of the construct of minimal fluidization velocityA ( VA mfA ) A at which the bed merely begins to fluidize. Thus the primary concern is to mensurate and optimise theA VA mfA for efficient fluidization.
Fixed, Fluidized, and Mobilized beds
( a ) Slow flow rate ( B ) Intermediate flow rate ( degree Celsius ) High flow rate
Fixed bed Fluidized bed Mobilized bed
VA 0A & lt ; VA mfA VA mfA a‰? Vo & lt ; UA tA VA 0A a‰? UA T
Figure -1. Fixed, Fluidized, and Mobilized beds.A ( 9 )
TheA fixed bedA ( a ) A occurs when the attack speed or superficial speed, A ( A VA oA ) A , is much smaller than the minimized fluidization speed, ( A VA mfA ) .A TheA fluidized bedA ( B ) A occurs when the attack speed is intermediate between the minimal fluidization speed and the terminal speed. The pneumaticallymobilized bedA ( degree Celsius ) A occurs when the attack speed is much greater than the atom terminal velocityA , ( UA tA )
2.3.3 Determination of Minimum speed of fluidization ( VA mfA ) A ( 8 )
The finding of minimal speed of fluidization plays a critical function in efficient operation of a fluidized bed system. Establishing on the nature of size distribution of a solid bed VA mfA computation differs.
Pressure bead with diminishing superficial speed
Figure- 2 ( a ) . Pressure bead with diminishing superficial velocityA ( 8 )
Pressure bead with increasing superficial speed
Figure -2 ( B ) .Pressure bead with increasing superficial velocityA ( 8 )
e.g. if the solid bed contains solids of unvarying denseness VA mfA computation is done establishing on the equation developed by ErgunA ( 8 )
If the solid bed is holding broad size distribution of atoms ( i.e. bed contains solids with differing densenesss ) VmfA finding is correspondent to measuring of boiling point of a liquid mixture, the boiling point of mixture is non fixed but varies with composing. Besides VA mfA can be determined utilizing mean atom size of the bed.
2.3.4 Role of force per unit area bead in FluidizationA ( 8,9 )
When a fluid flows through a bed of atoms in a tubing, it will exercise a retarding force force upon the atoms ensuing in a force per unit area bead across the bed. As the fluid ‘s attack speed is increased, force per unit area bead is magnified.
In an unrestrained bed with fluid fluxing upwards through it, a status will be reached where, with increasing fluid speed, the retarding force forces will do the bed to spread out. This enlargement allows the atoms to offer less opposition to the fluid flow. When the retarding force force is sufficient to back up the weight of the atoms in the bed, the bed is said to beA fluidizedA . The fluid/solid system shows fluid-like belongingss, and the bed can be made to flux from one vas to another.
The force per unit area bead across the bed, a?†p, so remains changeless ( even with farther addition in the fluid speed ) and equal to the effectual weight of the bed per unit country
When the unit is operated at force per unit areas comparable to atmospheric, thereforeA ImageA is negligible compared withA ImageA . As the gas speed, VA 0A , is raised beyond that required to convey the bed to a fluidized status, i.e. beyond the minimal fluidization speed VA mfA , the bed will get down to bubble. This status is called aggregativeA fluidizationA . ( 8 ) A If the gas speed were increased overly, the bubbles would turn so big that they would about or wholly make full the cross-section of the tubing forcing bullets of atoms organizing aA sloging bed.A ( 8 )
If the fluid were more dense, ( e.g. a gas at the high inactive force per unit area of a liquid ) , or if the atoms were finer ( 20 to 100 Aµm ) and less lairs ( & lt ; 1400 kilogram mA -3 ) A , the bed would be able to prolong a grade of stable enlargement, besides known asA particulate fluidization.A ( 8 ) A The bed would stay stable until the VA mfA had been exceeded by a factor of 2 or 3. In contrast, when utilizing gas to fluidized a bed, the bed would fall in and reinitiate bubbling with farther addition in gas speed. A liquid fluidized bed normally continues to spread out stablely with increasing speed ensuing in a non-bubbling fluidized status known as aquiescent bedA ( 8 )
With finer, less dense and cohesive pulverizations, it is really hard to fluidize the bed at all, because the interparticle forces are so greater than the gravitative 1s. The atoms tend to lodge together, and the gas passes through the bed by blowing channels through it. ( Parameters To Be Controlled In Fluid Bed Systems ( Aulton M.E. , 2nd Edition “ Granulation ” , A Pharmaceutics “ The scientific discipline of dose signifier design, Churchill Livingstone, EdinburghA , A 373, 2002, Ansel C. , Allen L.V. , Popovich N.G. , 8th edition “ Tablets ” , A Pharmaceutical dose signifier and Drug bringing system, A B.I PublicationsA , A IndiaA , A 193 and 243, 2005 )
The parametric quantities that affect the concluding merchandise processed through fluidized bed systems can be enumerated as below.
3.1 Apparatus Parameters
1 ) Air distribution home base Position of the air distribution home base influences the airflow form inside the organic structure.
2 ) Shape of instrument organic structure Annular base gives better merchandise and fluidization.
3 ) Nozzle tallness in instance of coater and granulator. It plays critical function as in coating, the atomized coating solution should non acquire dried before making the tablet surface.
4 ) Positive and negative force per unit area operation
3.2 Procedure Parameters
3.2.1. In Drying Procedure
The undermentioned recess air parametric quantities are critical, and applicable in all procedures of drying, granulation and coating.
1 ) Temperature
As the recess air temperature increases the rate of drying additions andA frailty versa.A This attack to increase the rate of drying can non be used ever because some stuffs are harmed by high temperature, e.g. Ibuprofen liquefies above 60A°C temperature of recess air should be optimized without any impact on merchandise quality. If temperature is high, it leads to vesicate. If temperature is low, soft topographic point can be formed.
2 ) Humidity
Humidity in the recess air should be every bit low as possible and ideally dehumidified air should be used for faster drying rate because as the humidness of recess air decreases the rate of drying additions.
3 ) Air flow rate
Air flow rate should be controlled decently in order to acquire efficient usage of drying air. As the air flow rate additions, the rate of drying additions but the cost of drying besides increases. If drying air is allowed for sufficient clip to stay in contact with the drying stuff, proper heat transportation and mass transportation takes topographic point and therefore drying cost lessenings. Air flow rate should non be excessively fast or excessively slow but optimized to hold efficient drying.
3.2.2. In Granulation Process.
Related To Spray Nozzle
1 ) Nozzle place in relation to material tallness.
Nozzle place is determined on bases of bed tallness and it should be placed appropriately for better contact of binder with the pulverization to be granulated.
2 ) Spray rate.
It should be optimized otherwise hapless wetting/agglomeration of the merchandise will take topographic point impeding the fluidization and quality granule formation.
3 ) Spray force per unit area.
It is of import for proper atomisation of binder solution.
1 ) Pressure bead across exhaust filters.
2 ) Outlet gas temperature.
The above two parametric quantities give indicant of the efficiency of the fluidization procedure. System ‘s degree of efficiency can be drawn from mensurating these two parametric quantities.
3.2.3. In Coating Procedure
Related To Spray Nozzle
1 ) Distance of spray nose.
Efficiency of surfacing depends on the quality of the surfacing solution. The surfacing solution should non acquire dried before making the fluidized substances viz. tablet, atoms, and granule surface.
2 ) Droplet size.
Quality of the coat depends on the droplet size. So it should neither be excessively large nor be excessively little.
3 ) Spray rate.
Flow rate should non be excessively fast or excessively slow, but should be of optimized rate for efficient coating.
4 ) Spray force per unit area.
Atomization of surfacing solution depends on the spray force per unit area, therefore for proper atomisation droplet size should be optimal.
1 ) Moisture content in treating compartment. Moisture should non be present in instance of hygroscopic stuffs.
2 ) Method used for surfacing should be chosen on footing of the intent for which it is used. e.g. SR, ER, etc.
3 ) Time of drying should be determined on bases of the merchandise and quality of the coat desired.
3.3. Merchandise Parameters.
3.3.1. In Drying Process.
1 ) Initial wet content of stuff.
It should non be high otherwise it increases drying clip.
2 ) Batch size.
It should be little and optimized based on feasibleness.
3.3.2. In Granulation Process.
1 ) Granulating agent.
Type of graining agent is based on choice of dissolver to be used in binder solution. This dissolver should be sooner aqueous as organic may do detonations. Binder solution used to grain the stuff should be used in optimal concentration so as to obtain good quality of granules. Temperature of graining agent should non be high otherwise it will be dry before making to the pulverization surface.
2 ) Get downing stuff.
Fluidization of get downing stuff should be optimized for better contact with the granulating agent. If the get downing stuff hydrophobic, hydrophilic granulating agent is to be used for better contact and granulation of stuff.
3.3.3. In Coating Process.
1 ) Coating agent.
Choice of surfacing agent should be done harmonizing to type of coating required e.g. Enteric coating, Sugar coating, etc. Solvent should be selected harmonizing to the belongingss of the coating agent. If solvent is volatile, it should be checked for inflammability. Concentration of graining agent should be optimized for unvarying spreading and droplet formation. Temperature of the coating agent should non be so high that surfacing solution acquire dried before making to the tablet surface.
2 ) Get downing stuff.
Shape of tablets greatly affects the coating procedure. In instance of pulverization surfacing the atoms form and denseness affects the coating procedure.
4. Categorization Of Fluidized Bed SystemsA ( Swarbick )
4.1. Harmonizing To Process ApplicationsA
The fluidized bed driers available for usage in the Pharmaceutical industry are of two types,
1 ) Batch type VerticalA Fluid Bed DryerA with Granulating option.
I.Reverse turning bed type
II.Rotating discharge type
2 ) Continuous type Horizontal Vibrating ConveyorA Fluid Bed Dryer.
The fluidized bed driers available for usage in the Pharmaceutical industry are of two types,
1 ) Top Spray Fluid Bed Granulator,
2 ) Revolving disc Fluid Bed Granulator with Dryer option.
The fluidized bed driers available for usage in the Pharmaceutical industry are of three types,
1. Top Spray Pellet with Particle Coating option,
2. Fluid Bed Bottom Spray Pellet with Particle Coating option,
3. Fluid Bed Roto Processor with Drug Loading & A ; Coating option.
4. Huttlin Kugel Fluid Bed Coater
4.2. Harmonizing To Principle
1 ) Spiral Granulator,
2 ) Bottom spray coating,
3 ) Tangential spray roto processor.
Categorization harmonizing to rule
Figure – 3 Categorization harmonizing to rule
5. Equipments For Fluidized Bed SystemsA ( 8,12-17 )
5.1A Fluidized Bed Dryer
Fluid bed drying is most widely used technique for drying pharmaceutical pulverizations and granulation. The direct contact between atoms and air/gas is possible in fluid bed system. Here any type of inert gas or air is used. They can be designed in either batch or uninterrupted type fluid bed drier. Assorted inventions in fluid bed drying are discussed in subdivision 7.
The fluid bed drying operates under the rule of direct drying where direct contact between a heated gas/air and the merchandise occur to consequence heat and mass transportation. The hot air/gas used for drying can be generated by either steam coils or a burning furnace. The holes in the pierced home base are covered with caps that prevent material signifier come ining the plenum when the drier is non in operation. The fan equipped in the upper portion of the setup induce fluidizing air watercourse.
Hot air is fed in the stuff bed at remainder from the underside of gas unbending valve ( e.g. pierced home base ) . The speed of air is adjusted by agencies of a damper. When the speed of hot air accelerates a spot, atom groups bit by bit come to do active motions bit by bit ensuing in hot air force per unit area loss due to the stuff beds comes to be in proportion to the weight of stuff atoms on the unit country of the unbending vane. With farther speed uping the speed of hot air, the atom groups undergo vigorous motion to blend with gas in all waies, ensuing in suspension province.
If all the atoms are to the full supported by air/gas so a bed may be fluidized good. The solid become partly suspended in gas watercourse when the speed of gas is greater than the settling speed of the atoms and less than the speed for pneumatic conveyance. The solids in this province are said to be fluidized and the attendant mixture of solids and gas/air behaves like a liquid. The angle of rest of gas-solid mixture is zero and it assumes the form of the vas that contains it. In fluid bed drying unvarying conditions of temperature, composing and atom size distribution is achieved throughout the bed because of complete commixture between the solids and gas is obtained.
When the stuff bed approaches to a certain flow speed ( i.e. minimal air speed for fluidization ) , it makes a minimum enlargement doing atoms traveling and taking to minimal fluidization.
Assorted stairss in fluid bed drying.
Figure- 4. Assorted stairss in fluid bed drying.A ( 12 )
The stuff subsequently expands to 1.2 to 1.6 times in tallness that was at resting position.A 1A Product tallness in the fluid bed ranges between 100 to 500 millimeters ( mean 300 millimeter ) depending on the application. The stuff bed behaves as it is liquid and shows an visual aspect as it is boiling. This province is termed as “ unstable province ” . This type of fluid bed can be formed within a certain scope of flow speed depending upon atom size, specific gravitation and other belongingss of the stuff.
Uniform processing conditions are obtained by go throughing hot air ( or other inert gas ) through a material bed under controlled speed conditions to make a fluidized province. Air is filtered after drying in multicyclones and /or bag filters. However, the usage of bag filter is troublesome if the drier is frequently used for different merchandises because careful cleansing of the drier is required.
The dry merchandise overflows an adjustable weir home base and is discharged continuously through a rotary air lock. In fluid bed drying, airflow need non be the lone beginning of heat. Heat can besides be efficaciously introduced by heating surfaces ( panels or tubings ) immersed in fluidized layer.A ( 14 )
Fluid bed drier can besides be constructed with an built-in chilling system therefore avoiding the demand for a separate ice chest in those applications that require one. In fluid bed chilling normally ambient or conditioned air is used. Another option is chilling surfaces immersed in the fluidized bed. Conditioning of the air may be required to obtain sufficient merchandise chilling in an economically sized works and to forestall pick up of volatiles including moistures.A ( 14 )
Fluid bed drier is suited for pulverizations granules, agglomerates and pellets, holding mean atom size usually between 50 and 5000 micrometer.
The stuff incorporating really all right, light pulverization ( low denseness ) or extremely extended atoms may necessitate quiver for successful fluid bed drying.A ( 14 )
Most unstable bed driers are individual base on balls system where the procedure gas passes through the bed merely at one time and is exhausted to atmosphere. Depending on the economic feasibleness of the operation, some systems can be designed for recirculation or convalescence. The larger atoms that fall out of bed are introduced back into the bed or propelled along the length of drier by vibrating action. Vibrating systems lessening power demands for fluidization and therefore cut down runing cost.A ( 15 )
In indirect fluid bed processing, a tubing or series of home bases are incorporated into the drying chamber. They are arranged in such a manner that merchandises remain in intimately contact with the het surface. The heat energy is transferred by agencies of conductivity. Here steam is used as a beginning of energy. The cost of operation is low because steam is low cost energy source.A ( 15 )
A fluid bed drier is capable to utilize about any heat beginning. As the temperature of the procedure gas is increased, the volume of air required is little and the unit required is besides small.A ( 15 )
With the right design, fluid bed driers can defy at highly high temperatures, supplying the possible for calcining. Incorporation of furnace lining run alonging the box, drying chamber or enlargement chamber is required with these designs. With independent control of air flow and temperature, the drier can be divided into several different zones. This design is utile for sensitive merchandises or where changing the recess temperature can profit the procedure. The advantage of this design is that drying can take topographic point at the maximal desirable rate in each phase by keeping efficiency and forestalling harm to the heat sensitive stuffs. The breadth of drier scopes from 12 to 57 inches and length scopes from 10 to 50 pess. The bed deepness is about 3 inches. Dryer capacity is dependent merely on keeping clip produced by velocity of conveyance, which by and large ranges from 5 to 25 pess per minute.
The fluid bed drier can be operated in either unfastened or closed rhythms. Using a solvent recovery system & A ; an recess gas similar N as the drying medium, the operation of the fluid bed drier can be carried out in a closed rhythm. A cyclone or febric aggregator, and a capacitor to take the solvent clean blowhole gases. The cooled, concentrated gases can be heated and utilised further.A ( 16 )
5.1.3 Types Of Fluid Bed DryerA ( 8,17 )
( 1 ) Batch Type Vertical Fluid Bed Dryer With Granulating Option.
In batch-type drier, the drying chamber is equipped in such a manner that it can be removed from unit to allow bear downing and dumping. The drier is capable of drying 5 kilogram to 200 kilograms stuff with an mean drying clip of approximately 20 to 40 min.
Batch fluidized bed drier
Figure-5. Batch fluidized bed dryerA ( 6 )
I. Change by reversal Turning Bed TypeA ( 17 )
In this equipment, by turning the gas scattering home base ( the contrary turning bed ) in 90A° way with the control motor, all the dried stuff can be discharged at one time.
II. Revolving Discharge TypeA ( 17 )
Dried stuff is discharged by opening the discharge gate equipped at the side of the Dryer. As the pierced home base is used as the gas scattering home base, the gas inside the equipment commotion and pushes the dried stuff out from the discharge gate.
Features Of Batch Type Fluidized Bed DryerA ( 17 )
The abode period of the dried stuff can be controlled which consequences in unvarying drying. It is most suited in instance where an accurate control of the abode period is required at the diminishing rate drying zone. Small devastation of atom occurs hence suited for farinaceous or crystallized stuff.
Easy operation can be achieved by an automatic control of stuff eating, drying dispatching etc. When multiple phase system us adopted, the fumes gas heat can be used expeditiously.
( 2 ) Continuous Type Horizontal Vibrating Conveyor Fluid Bed Dryer.A ( 17 )
The dried stuff is moved to a following during chamber through a spread at the underside of the divider home base and after eventually dried, the stuff is discharged over the overflow gate. For big volumes of stuffs, a uninterrupted drier is more suited than a batch type. The uninterrupted Fluid bed drier which is suited for pharmaceutical usage is horizontal vibrating conveyor drier shown in figure-7.
The het air enters the chamber below the vibrating conveyance deck. The air so passes through perforated conveyance surface and enters into the wet bed of stuff and causes fluidization of the atoms.
Due to vibrating motion of the conveyor, a fluidized bed of unvarying denseness and thickness is maintained in any given drying zone.
Residence clip in any drying zone is dependent on
( 1 ) Length of the zone
( 2 ) The frequence and the amplitude of the quiver
( 3 ) Use of dikes
Horizontal multiple Chamberss fluidized bed drying and chilling system
Figure -6. Horizontal multiple Chamberss fluidized bed drying and chilling systemA ( 12 )
Heat Transfer Unit Built In Continous Fluidized Bed DryerA ( 17 )
Heat reassign units such as tubing or home base, are built inside the equipment. These unit supplies 60-80 % heat necessary for drying. Thus the measure of hot air is decreased, cut downing the power ingestion and operating cost. The equipment becomes compact. The subsidiary equipment can besides be miniaturized.
Features Of Continous Fluidized Bed DryerA ( 17 )
( 1 ) The stuffs with comparative high wet content can besides be dried.
( 2 ) At and after a 2nd drying chamber, Piston flow ability can be achieved by set uping Numberss of the divider plates as per the needed abode period. The pierced home base at the fixed way ensures easy discharging.
( 3 ) Small devastation of atoms, so suited for granules or crystalline stuffs.
In multiple zones fluid bed driers, warming and chilling occurs in same unit. Each zone has independent control for temperature, dewpoint and speed of air/gas. By seting the weir tallness for each zone, abode clip can change up to four crease in the unit.
5.2 Fluidized Bed GranulatorA ( 1, 14, 18, 19 )
5.2.1 IntroductionA ( 19 )
The basic construct in granulation ( besides known as agglomeration ) involves suspending particulates in an air watercourse and spraying a liquid from the top on to the fluidized bed. Atoms in the way of the spray acquire somewhat wetted and become tacky. The tacky atoms collide with other atoms and adhere to them to organize a granule.
There are two different manner of fluid bed granulation:
1 ) Dry phase
2 ) Wet phase
In theA dry phase granulationA , the graining solution is applied at a rate less than or equal to the vaporization rate so that the atoms are wetted somewhat to go tacky and stick to each other. Thus the atoms remain “ dry ” through the full procedure.
In theA wet phase granulationA , the graining solution is applied at the rate higher than vaporization rate until the atoms build up plenty wet to grain so that atoms are wetted significantly before they become tacky plenty to lodge to each other.
Dry phase granulation is more common than wet phase granulation which allows for denser merchandises.
Three Techniques Are Used For GranulationA ( 1 )
1. If the pulverization stuffs are soluble in the dissolver ( normally H2O ) , during drying crystalline span signifier & A ; keep the granules together ( recrystalization ) .
2. If the pulverization stuff insoluble in the dissolver or stronger binder is required, a binding agent is used for granulation ( as indurating agent ) .
3. To construct agglomerative get downing with a substrate and adding alternate bed of binder and active stuff until a coveted size of granules form ( every bit known as layering ) .
5.2.2. Instrumentality And Operation
InstrumentationA ( 14 )
Fluid bed granulator
Figure-7. Fluid bed granulator
1. Inlet air filter
4. Inlet air Heater
5. HEPA filter
6. Inlet air
7. Inlet air plenum
8. Gas distributer home base
9. Merchandise container
10. Conic enlargement zone
11. Filter lodging
12. Merchandise filter
13. Outlet air
14. HEPA filter
16. Spray gun
A suction fan mounted at the top part generates the airflow necessary for fluidization of pulverizations. The air used for fluidization is heated to the desired temperature by an air warmer. The liquid granulating agent is pumped from its container & A ; sprayed as a all right mist through a spray caput onto the fluidized pulverization. The wetted atoms undergo agglomeration through atom contacts. After appropriate agglomeration is achieved, the spray operation is discontinued and the stuff is dried and discharged from unit.
5.2.3. Principle Of GranulationA ( 18 )
The pulverization is fluidized by the hot air in fluid bed granulator. The adhering liquid such as solution, suspension is sprayed on the fluidized pulverization to construct liquid Bridgess among them to organize agglomerates.
The liquid span that serve to keep the atom together in two ways ( 1 ) by surface tenseness at the air liquid interface ( 2 ) by hydrostatic suction.
The liquid Bridgess are dried by the hot fluid air to lodge the pulverization together. While the liquid sprayed continuously, the atoms turn bigger to a desire granule size. The procedure is carried out continuously. Finally it forms ideal, unvarying and porous granules.
Principle of granulation procedure
Figure-8. Principle of granulation procedure
5.2.4. Types Of Fluidized Bed GranulatorA ( 1 )
1 ) Top Spray Fluid Bed Granulator
The recrystallization and indurating binder engineering are by and large carried out in the top spray granulator. In this equipment spray nozzle located at the top the base of the merchandise container is equipped with a all right – mesh keeping screen to let little atom size. Spray nozzle to allow positioning above the inactive bed in the elongated enlargement chamber. The granulator is operated by fluidizing the bed of pulverization & A ; spraying the graining solution at the controlled rate. Proper agglomeration achieved, the liquid spray is cut away and the stuff allows drying to the coveted wet content.
2 ) Revolving Disk Fluid Bed Granulator With Dryer Option
Layering engineering carried out by revolving disc granulator and coater. The technique have been extended to surfacing operation and combined with an enlargement chamber to organize the revolving disc granulator & A ; coater fluid bed device.
The revolving disc can be moved up or down to make a variable slit opening between the outer margin of the disc and the side wall of the container.
This allows independent control of air speed over air volume, air is drawn into the merchandise container through the slit under negative force per unit area. At the same clip the disc rotate at changing velocity & A ; merchandise move under centrifugal force to the outer places where it is lifted by the fluidizing air watercourse into the enlargement chamber. As the stuff autumn to the centre of the revolving disc and reiterate the procedures. This fluidization form besides described as a gyrating spiral or rope like form around the inside the rotor chamber.
The gesture of fluidization of the atom controlled by the forces like fluidization, centrifugal force and gravitation.
Spray nozzle immerged in the bed of fluidization and spray applied in digressive manner with regard to the atom flow.
Pallet production by the layering technique, in this procedure started with seed stuff ( smaller as diameter 250 millimeter ) . The solution or suspension of the drug and binder can be applied to the seed stuff in several beds. Drugs can use as a dry pulverization fed into the bed at a controlled rate. So that bed expands both horizontal and perpendicular, layers up to 1000 % at get downing weight can be applied. The ensuing pellets formed are unvarying and later coated for controlled release.
In the layering technique dry pulverization can be fed into the moisture bed ensuing in the physique up the beds of the pulverization on to the atom substrate. At the terminal of the coating procedure the liquid spray is cut away and the stuff in the merchandise chamber is dried by increasing the fluidizing air volume and temperature.
5.2.5. Park Problem In Fluid Bed GranulationA ( 18 )
1 ) Excessive mulct
– In sufficient measure of binder
– High fluidized speed or air flow
– Weak binder or low concentration of spraying liquid
– Inlet temperature excessively high
– Binder spray rate is excessively low
– High atomisation air force per unit area
– Fine droplet size of the binder.
2 ) Excessive coarse granulation
– Binder spray rate excessively high
– Inlet air temperature excessively low
– Low fluidization speed or air flow
– Stronger binder or higher concentration of spraying liquid.
– Nozzle place excessively low
3 ) Final wet incompatibility
– Improper fluidization
– Temperature probe out of standardization
– Humidity of outside air
4 ) Poor fluidization
– Air speed is low
– Processor fan does non hold equal force per unit area bead
– Air distributer non cleaned decently
– Too much merchandise in the merchandise container
– Incorrect air distribution home base
– Exhaust filter porousness to little
– Exhaust is blocked
5 ) Finished merchandise non uniformity
– Insufficient filter agitating
– Merchandise homogeneousness before granulation is non equal
– Ball in natural stuffs
– Crop-dusting clip is deficient
6 ) Low output
– Filter bag is non shaked at the terminal of the procedure
– Material stick to the enlargement Chamberss as a consequence of inactive charge
– Incorrect porousness exhaust filter
– Air distributer with coarser screen opening
In the system, a granulating solution or dissolver is sprayed into or onto the bed of suspended atoms. The rate of add-on of binder or dissolver, conc. of binder, spray rate, distance between spray nose & A ; fluid bed, temperature of air, volume & A ; wet content of the air all play of import function in the quality & A ; public presentation of the concluding merchandise
In general fluid bed granulation outputs less heavy atoms than conventional methods.
5.3 Fluidized Bed CoaterA ( 1, 8, 20 )
5.3.1 IntroductionA ( 1 )
Pharmaceutical dose signifiers like tablets, pulverizations, granules and pellets are frequently coated with polymeric stuff to dissemble obnoxious gustatory sensation or olfactory property, protect an unstable ingredient to divide incompatible ingredient, better visual aspect for enteral coating and sustained release coating. So many methods are used for using surfacing to the nucleus stuff including fluidized bed coating.
Figure-9. Features of fluidized bed coating
5.3.2. Instrumentality And OperationA ( 1 )
1 ) Incoming Air
It should be direct contact with the merchandise and be free from air born dust, oily atoms, other drosss. The air should be filtered through both harsh and all right dust filters and besides from HEPA filters if required. Cooling with cool H2O or infrigidation agents or go throughing through adsorbent agents should dehumidify it.
2 ) Merchandise Container
The merchandise container should be made up of high quality polished chromium steel steel holding suited form and size. The bottom portion should keep a screen of the right size required to catch the merchandise. It may besides be equipped with discharge pneumatic devices, choppers to interrupt balls of granules during processing, particular film-coating dividers and noses to spray fluid from below.
( 3 ) Filter Bag Housing
The filter bag & A ; lodging are really of import parts of fluidized bed equipment. Manufacturers patent the no, design, size, form and other features of filter bag lodging. The filter agitating device and filter below off device are used for cleaning the filters.
( 4 ) Spray Device
This device used to administer the firmly atomized and homogenized granulating or surfacing liquid on to the fluidized merchandise. One fluid noses, which atomize liquid by its ain force per unit area against the nozzle tip, and two fluid noses where high-pressure air is introduced at the nozzle tip to interrupt the liquid into all right droplets. The latter one is most widely used since it places, much finer droplets.
Different types of pumps are employed to travel the liquid and atomized air to the noses.
5.3.3. Types Of Fluidized Bed CoaterA ( 1, 8, 20 )
( 1 ) Top Spray Pellet With Particle Coating Option,
This is known as down-spray coating
The enlargement chamber is lengthened leting pulverization to stay fluidized longer and to travel with a higher speed so that agglomeration is minimized. The enlargement chamber is conelike shaped leting unvarying slowing of the air watercourse. The filter lodging is larger. Its design allows to agitate the mulcts back into so bed without disrupting fluidization, this reduces inclinations of agglomeration. The nose is kept low in the enlargement chamber, so that surfacing stuffs impinge on the fluidized particles a short distance from the nose, this reduces droplet spray – drying and provides for longer subsequent drying of the coated atoms.
Top spray coater is used
To use aqueous and organic dissolver based movie surfacing
A§ Controlled -release coating
A§ Hot thaws on granules & A ; little atoms
Top spray coating
Figure-10. Top spray coating
2 ) Fluid Bed Bottom Spray Pellet With Particle Coating Option,
This coater employs a cylindrical merchandise container with a pierced home bases. In the container, there is a 2nd cylinder ( surfacing divider ) , which is raised somewhat above the pierced home base.
Centrally, in the home base below this divider, there is a nose used to distribute the coating solution. The pierced home base is designed with big holes in the country under the coating divider & A ; smaller holes in the balance of the home base, excepting the one ring, of larger holes at the margin. Bottom-spray coating provides a extremely organized atom flow & A ; high quality consistent movie so this system is used extensively for sustained release coating. This procedure is capable of managing dissolvers, Aqueous Solutions, emulsions, suspension, movies & A ; hot thaws. It is used for surfacing little atoms, pellets & A ; tablet with batch size from a few hundred grams to 600 kilograms.
3 ) Fluid Bed Roto Processor With Drug Loading & A ; Coating Option.
This is the technique in which fluid bed system utilizes revolving disc to add centrifugal force to the forces of fluidization and gravitation and offers really rapid commixture.
The atoms cycling clip in digressive spray fluidized bed equipment is really rapid so the movies are unvarying in thickness.
Rotoprocessor insert ( Digressive spray insert )
Principle of operationA
The rule of operation is that digressive noses are fixed on the revolving home base such as to make different operation utilizing the same insert. The revolving home base is a specially designed perforated home base such that the pulverization does non fall down and at the same clip air can come through the home base making fluidized consequence in the processor.
The uniformity is good and the wastage is the lower limit as the spray nose is embedded within the bed.
Operationss possible: –
Pellet formation, Pellet drug lading on silent person beads.A
Concave tablet coating.
Spray application systems: –
1 ) High force per unit area, air less
2 ) Low force per unit area, air atomized
Spray application systems
Figure-13. Spray application systems
4 ) Huttlin Kugel Coater: –
It does non dwell of a cardinal processor. The merchandise container of kugel coater is spherical. Fluidized air is introduced by tubing that passes down the centre of the merchandise container. A series of spray noses are besides located at the underside of the merchandise container in such a manner that fluidizing air creates a balloon consequence to maintain the merchandise being coated off from the spray noses. Addition of multiple spray noses intended to maximise uniformity of distribution of coating.
Huttlin kugel coater
Figure-14. Huttlin kugel coater
5.3.4. Design FeaturesA ( 1 )
1 ) GMP
As per GMP ordinances the merchandises prepared for human usage meet certain minimal quality criterions. A surface of container should be made up of high quality polished unstained steel. Joints should be absolutely welded with a extremely polished coating. Components should be easy dismantled and orderly.
2 ) Safety demand
In instance of fluidized coater vast of sum of heated air is used and when this air mixes with dissolver and dust, an explosive mixture can ensue. Adequate safety devices are required to forestall devastation of the machinery and hurt to the operating staff.
In instance of an explosive ( force per unit area of 9 to 12 saloon ) horizontal and perpendicular force per unit area, sufficient panels of alleviation doors are needed. Explosion cogent evidence and waterproof motors and electrical switches are common characteristics of advanced engineering.
3 ) Solvent recovery
The surfacing done in fluidized bed system, the complete dissolver remotion is non possible, the fumes gases incorporating organic dissolvers bluess of toxic stuffs must non be automatically vented into the ambiance.
These gases should non be treated by solvent recovery system for filtration device to diminish the emanation to the minimal sum allowed by jurisprudence and to forestall environmental pollution.
5.3.5. Influence Of The Spray NozzleA ( 20 )
Low vs. high
( 121 vs. 168 millimeters above distributer )
Influence of the spray nose
Figure-15. Influence of the spray nose
Nozzle force per unit area:
Maintenance vs. 2 vs. 3 vs. 4 bars
Sodium caseinate V.
5 – 7.3 g/min
Coating liquid dry affair:
5 – 15 wt %
5.3.6. Particle Motion VisualizationA ( 20 )
OpticalA : A Behavior along the wall
Probes: e.g. Fiber optical, electrical capacity, induction
Invasive technique: local gesture perturbation
PIV, LDA: Crystalline equipment/materials required
Magnetic resonance imaging: Material do non incorporate metal parts
Imaging: e.g. Capacitance hapless declaration, blurred consequences
Tracer techniques: Non-invasive technique. Real-time recording is possible High temporal and spacial declaration. e.g. Positron emanation atom tracking ( PEPT )
6. Advantages, Disadvantages And Applications Of Fluidized Bed SystemsA ( 8, 9 )
Liquid like behaviour, easy to command
Rapid commixture, unvarying temperature and concentrations.
Resists rapid temperature alterations, hence responds easy to alterations in operating conditions and avoids temperature blowout with exothermal reactions.
Applicable for big or little scale operations.
Heat and mass transportation rates are high, necessitating smaller surfaces.
Ease of procedure control due to stable conditions.
Bubbling beds of all right atoms are hard to foretell and are less efficient.
Particle comminution ( dissolution ) is common.
Pipe and vas walls erode due to hits by atoms.
Non-uniform flow forms ( hard to foretell ) .
Size and type of atoms, which can be handled by this technique, are limited.
Due to the complexness of fluidized bed behaviour, there are frequently troubles in trying to scale-up from smaller graduated table to industrial units.
Abrasion of solids.
6.3 ApplicationsA ( 8, 9 )
Degree of application decides importance of procedure. Fluid bed systems are widely applied in non- pharmaceutical Fieldss in comparing to their usage in pharmaceutical Fieldss as there are legion setups, procedure and merchandise parametric quantities that affect the quality of concluding pharmaceutical merchandise. Besides in pharmaceutical field each preparation presents its ain single development jobs that had led to fluidized systems non making its full potency in pharmaceutical production:
Fluidized bed driers are used in drying of assorted stuffs such as pulverizations, tablets, granules, coals, fertilisers, fictile stuffs.
This procedure is being used in granulation of pharmaceutical pulverizations.
Fluidized bed coaters are used widely for coating of pulverizations, granules, tablets, pellets, beads held in suspension by column of air.
The three types ( Top spray, Bottom spray, Tangential spray ) are chiefly used for aqueous or organic solvent-based polymer movie coatings.
Top-spray fluidized bed coating is used for gustatory sensation cover, enteral release and barrier movies on particles/tablets. Bottom spray coating is used for sustained release and enteral release and Tangential spray coating is used for SR and enteral coating merchandises.
Applications of Fluidization –
A Fluidized bed dryer [ hypertext transfer protocol: //www.kason.com/fluidbed/principle.php ] -A With the rule of fluidization, drying can be carried out. In aA fluidized bed drier, hot air watercourse at high speed is passed from the underside of a pierced basket incorporating the stuff to be dried.
Fluid energy factory [ hypertext transfer protocol: //www.cn-pharmaceuticalmachinery.com/product/Product-200.html ] -A Size decrease can besides be carried out by fluidization as the chief rule by unstable energy Millss. In these Millss, high speed air is allowed to come in the milling chamber through digressive noses. Along with the air, the atoms will besides raise. Due to attrition in between the atoms milling is accomplished.
Fluid granulator [ hypertext transfer protocol: //www.cjtech.co.kr/Technical % 20Process % 20Fluid % 20Bed % 20Granulation.htm ] -A Granulation of pulverizations can be done by following fluidization. A granulating solution is sprayed on to the fluidized ingredients by which granulation is accomplished.
Fluidized bed Coater [ hypertext transfer protocol: //www.cjtech.co.kr/Technical % 20Process % 20Fluid % 20Bed % 20Coating.htm ] -Here surfacing solution is sprayed on to the fluidized pulverizations, microspheres etc
7. Inventions In Fluidized Bed Systems ( Walter K.T. , A Process for Granulation of a Particulate Material.A European PatentA 1064990 ( 2001 ) )
7.1. Pulsed Fulid Bed Dryer ( Liew C.V. , Walter K.T, Wigmore A.J, Brzeczko A.W. and Heng P.W.S, Precision Granulationa„? as an Alternate Granulation Method, A Poster Presented at 2002A AAPSA Meeting and Exposition, Toronto ( Nov 2002 ) . ( worldwide patented engineering: CA2236290 ; DE69813207 ; EP0979140 ; GB2324744 ; US5918569, WO98/48932 ) , ( Technology licensed to Aeroglide Inc. , P.O. Box 29505, Rayleigh, North Carolina 27626-0505 U.S.A. ; )
In pulsed fluid bed drier, at a given clip period, the fluidizing gas flows through a fraction of grid surface country and is so redirected to back-to-back subdivisions in fast sequence ( the gas plenum chamber is divided into several subdivisions ) . While in conventional fluid bed drier, the fluidizing gas flows through the full surface country of grid surface.
Pulsed fluid bedA Conventional fluid bed
A. Pulsed unstable bedB. Conventional fluid bed
Figure-16. Comparison between conventional and pulsed fluid bed dryer.A ( 23, 24 )
Advantages of pulsed fluid bed over conventional unstable bed.
A· For easy fluidization for irregularly shaped atoms such as fibres, flakes, acerate leafs
A· For fluidization of stuff holding a broad atom size distribution
A· For fluidization of bed of atoms with 30 to 50 % less air
A· It operates with improved fluidization uniformity ( decreased channelling )
A· For fluidization of delicate atoms
7.2. Fluidized Spray DryerA ( 14 )
The Fluidized Spray Dryer FSDa„? is one frequently most successful designs of spray driers combines fluidization and spray drying engineerings, enabling the size and construction of atoms to be easy controlled. Therefore, the FSDa„? is frequently used as a spray drier agglomerator or spray drier granulator.
Another of import characteristic which makes this concept ideal for bring forthing heat sensitive merchandises in dried signifier.
System layout System layout
Figure-17. System layoutA ( 14 )
Produces free fluxing pulverizations in agglomerative or granulated signifier.
Produce pulverizations holding a really low content of little atoms ( dustless ) .
Many thermoplastic and hygroscopic merchandises those are debatable in other designs can be dried.
Ideal for heat sensitive merchandises as atom temperatures are kept low throughout the drying procedure.
Drying is completed at low mercantile establishment drying temperatures, giving high energy use efficiencies.
7.3. Preciseness GranulationA ( 21, 22 )
Fluid Bed Granulation and High Shear Granulation are soon the most of import wet granulation techniques employed in the pharmaceutical industry. Precision GranulationTM, a new underside spray method, is evaluated for comparing with the conventional granulation methods.
Precision granulation procedure
Figure-18. Precision granulation processA
The aim of this survey was to compare Precision Granulationa„? ( PG ) with Top Spray Fluid Bed Granulation ( TS-FBG ) and High Shear Granulation ( HSG ) for tabletting.
Finally they conclude with:
PG produced good quality granules with equal flow and strength for tabletting. The quality of these tablets was comparable to those of tablets prepared from TS-FBG and HSG
Porosity, strength, majority denseness and tapped denseness of PG granules were intermediate to those of HSG and TS-FBG granules. PG granules had the lowest Carr index and Hausner ratio values. For tantamount tablet weight and hardness, PG tablet batches showed faster decomposition times.
Preliminary surveies with the two classs of milk sugar and powdered sugar suggested that PG can offer an option to bing methods for look intoing granulation of “ difficult-to-granulate ” stuffs.
Real Time Process Determination TM ( RTPD ) is a package plan that can be integrated with the granulator controls system for heightening procedure monitoring and control.
7.4. Multi Function Fluid-Bed Granulator and Coater ( Walter K.T. , A Process for Granulation of a Particulate Material.A European PatentA 1064990 ( 2001 ) . )
Vanguard ‘s VPL Series Fluid Bed Granulators and Coaters have multi-functional systems. The top spray system is the 3rd coevals of the top spray granulator. It is more efficient than most common fluid bed granulators in the industry. This type of advanced series equipment integrates three fluid bed processes including the top-spray granulating, underside spray coating, and tangent spray pelletting and coating such that it achieves both economical and technological advantages in solid dosage processing and other applications.
A· High efficient drier
A· Granulator meeting different demand
A· Bottom spray coating system
A· Tangent spray rotor system for pulverization layering, pelletting, surfacing
A· Intelligent control system
A· 2 saloon daze resistant as criterion