Coating equipment

priyanka shashikant gavali.m pharmacy from A.B.C.P.Sangli

1. COATING EQUIPMENT Presented By : Gavali Priyanka Shashikant M . Pharmacy 2st Semister Department Of Pharmaceutics Appasaheb Birnale College Of Pharmacy, Sangli . 1 A.B.C.P.Sangli

2. INTRODUCTION : Tablet coating is the application of coating material to the exterior of a tablet with the intention of conferring benefits and properties to dosage form over the uncoated variety. Why Tablet Coating is Required? A number of reasons can be suggested: The core contains a material which has a bitter taste in the mouth or has an unpleasant odour . Coating will protect the drug from the surroundings with a view to improve its stability . Coating will increase the ease by which a tablet can be ingested by the patient . 2 A.B.C.P.Sangli

3. The core contains a substance which is incompatible in the presence of light and subject to atmospheric oxidation , i.e. a coating is added to improve stability. The core alone is inelegant. The active substance is colored and migrates easily to stain hands and clothes. The coated tablet is packed on high-speed packaging machine. Coating reduces friction and increases packaging rate . Coating can modify the drug release profile , e.g., enteric coating, osmotic pump, pulsatile delivery. 3 A.B.C.P.Sangli

4. COATING EQUIPMENT: Most commonly used equipments are, The standard coating pan . The perforated coating pan . The Fluidized bed coater. 4 A.B.C.P.Sangli

5. Standard Coating Pan This consists of a circular metal pan between about 15 and 200 cm (6 to 80 inches) in diameter that is tilted on a benchtop stand. The pan can be rotated with an electric motor. A batch of tablets are loaded into the pan which is set to rotate. The rotating motion causes the tablets to tumble within the pan. Coating solution is applied to the rotating tablet bed by spraying in atomized form which can produce a faster and more even distribution than simply introducing it as a liquid. Drying efficiency can easily be achieved by an immersion sword – the drying air is distributed through a perforated metal sword that is immersed in the bed. 5 A.B.C.P.Sangli

6. Use of a baffled pan and diffuser (as marketed by pellegrini ) which allows the distribution of drying air uniformly over the surface of the tablets. An immersion tube system – the tube is immersed in the bed where the tube delivers heated air through the spray nozzle. Advantages of standard coating pan It is a continuous process Low drying time Can be use for both sugar coating and film coating The pellegrini system can improve drying efficiency A rapid method of coating and therefore takes less time to coat the tablet than other methods Takes less time to coat the tablet 6 A.B.C.P.Sangli

7. Perforated Pan This equipment consists of a partial or full perforated drum that rotates on its horizontal axis, the whole system being enclosed in a sealed housing. Examples are: Accela-cota /Hi-coater Systems – with this equipment, the drying air is directed to the drum, passing through the tablet bed and is released through the perforations in the drum. Driacoater – Similar to the Accela-cota in the Driacoater , channels for directing the supply and exhaust air the drying air are integrated into the drum wall as reinforcing elements. is introduced through a hollow area located inside the drum’s periphery. During the drying process, the drum rotates the dip into the tablet bed and dry air passes up through and fluidizes the tablet bed with the air exhausting through the back of the pan. 7 A.B.C.P.Sangli

8. Glatt coater – This design uses fully perforated drums – a feature which combines maximum spray rates and extremely short process times. The horizontal process air flow minimises turbulence in the nozzle area and therefore also contributes to a perfect coating result. The drum geometry and the glatt fischer baffles mix and protect the product at the same time, guaranteeing a very even and exceptionally high-quality coating. The drum is integrated in the unique GC smart housing, where all points are extremely easy to access; it is fully welded and the suspended drum is mounted at the rear without any front support to get in the way. 8 A.B.C.P.Sangli

9. Perforated pan system Drying air directly passes to the drum. Configuration of the air flow is possible in the case of the Glatt coater. Shows increasingly versatile coating capability. More efficient than other methods in drying of the tablet bed. 9 A.B.C.P.Sangli

10. fluidized Bed/Air Suspension System In a fluidized bed coater, the chamber is usually a vertical cylinder. Fluidization of the pellets is achieved by a column of air flowing upwards from the bottom centre of the cylinder. The tablets in the centre move upwards in the air flow and fall outwards and downwards to the chamber wall, re-entering the air stream from the bottom part of the column. Spray nozzles for introducing the coating solution are located in the bottom and top of the chamber. The tablet’s core is frail and is prone to abrasion and chipping making it difficult to fully coat the tablet even under optimum conditions. This is due to the rough tablet to tablet impact as well as the tablet chamber contact. There are two principal arrangements used to apply finely divided spray coating solutions to tablets: 10 A.B.C.P.Sangli

11. High pressure airless system – Airless spray liquid are pumped at high pressure of between 1.7 and 20 mpa (250 and 3000 psig) through a small orifice of between 0.02 and 0.2 mm diameter, which results to a finely divided spray. The degree of atomization degree and spray rate are all controlled by fluid pressure, liquid viscosity and orifice size. Low pressurized air atomized systems – The liquid is pumped through a larger orifice of between 0.05 and 2.5 mm diameter a relatively low pressure of 35 – 350 kpa (5 to 50 psig). The low pressure air contacts the liquid stream at the top of the atomizer and a finely divided spray is achieved. The atomization degree is controlled by the fluid cap orifice, fluid viscosity, fluid pressure, and air cap design and air pressure. 11 A.B.C.P.Sangli

12. Things to Consider in a Coating Machine Perforated drum coating machines are popular in the industry and the following need to be addressed when considering the purchase of a machine: Air capacity – the amount of air flowing through the bed will determine the amount of water or solvent that can be removed during the coating process. Coating composition – the coating composition includes the ingredients that are applied to the surface as well as to the solvent that acts as a carrier for the ingredients. The solvent is removed during the coating process by the flow of air through the coating machine. To speed up this process the incoming air can be heated, however, there is a fine balance between the rate at which solvent can be evaporated and the rate at which the coating liquid can be introduced. 12 A.B.C.P.Sangli

13. Tablet surface area – it is easy to weigh a batch of tablets that are to be coated, to give an idea of the amount of coating solution that needs to be applied. However, it is the surface area of the tablets that determines the total amount of coating solution required. The size of the tablets and nature of their surface can significantly affect the coating conditions and quantities of solution required. The total area/weight ratio decreases quite significantly from a smaller to a larger tablet. Efficiency of equipment – conventional sugar coating efficiency is not very efficient and 60% is deemed to be acceptable. The efficiency depends on the coating material that is collected on the pan walls. 13 A.B.C.P.Sangli

14. Main Coatings using a Coating Machine Coating is the final step in the production cycle of pharmaceutical tablets. To be successful, the final product must demonstrate enhanced visual appeal compared with uncoated products. Broadly there are two types of coating that may be applied to pharmaceutical tablets – sugar coating and polymer film coating. Sugar coating is the traditional means of coating tablets, and takes place in 5 distinct steps: Sealing Applying a subcoat Smoothing Applying a finishing coat 14 A.B.C.P.Sangli

15. Polishing Film coating is a more recent innovation and is applied in a single step using either a pan pour method or a pan spray method. Generally the same coating machine can be used for the both sugar coating and polymer film coating. The following are some characteristics and advantages of the three types of coating machines 15 A.B.C.P.Sangli

16. Conventional Pan System : It consists of a circular metal pan mounted somewhat angularly on a stand and is rotated on its horizontal axis by a motor . Heated air is directed into the pan and onto the tablet bed surface , and is exhausted by means of ducts positioned through the front of the pan. 16 A.B.C.P.Sangli

17. COATING PANS :- Upgraded Conventional Coating Pan Side Vented Coating Pan Conventional Coating Pan 17 A.B.C.P.Sangli

18. Drawbacks: Much of drying takes place on the surface of the bed of material being coated, thus dry efficiency is often low. Mixing efficiency can be poor, many dead spots may exists in the product bed . Improper balance between inlet and exhaust air can with organic solvent based film coating. A significant improvement in the particle movement & drying efficiency of the standard coating pan is achieved by the, Pellegrini pan Immersion sword Immersion tube systems 18 A.B.C.P.Sangli

19. IMPROVEMENT IN THE PARTICLE MOVEMENT Mixing of the core bed is important for a uniform application of the coating material as well as for effective drying. The most basic approach to improve the core bed movement in pans rotating on inclined or horizontal axes was to introduce baffles and blades in the pan. One of the first pans with a single baffle was invented by keil in 1965. The first coating pan rotating on a horizontal axis equipped with tapered side walls and an integral baffle system was introduced by pellegrini and is well-known as the pellegrini pan. 19 A.B.C.P.Sangli

20. PELEGRINI PAN: The side walls of this pan are shaped with a pronounced taper, which increases the efficiency of particle movement by forcing the cores into an additional lateral movement. This results in a composite core movement yielding improved exposure of the core to the coating material. 20 A.B.C.P.Sangli

21. USING BAFFLES AND BLADES INCREASES RISK of friction between the core material and the pans, potentially resulting in increased amounts of dust formed during the coating process. Hence, FOCUS was on the IMPLEMENTATION OF PERFORATED PANS to improve the air transport in the core bed and consequently to increase the mixing and drying efficiency . 21 A.B.C.P.Sangli

22. IMPLEMENTATION OF PERFORATED PANS: Hostetler , for instance, has modified the peripheral wall with perforations and positioned an air supplying inlet at the lower peripheral area, forming the so-called side-vented pan. The shape of the pan, the perforations in the peripheral wall, and the side positioned air supplying inlet were not only intended to increase core movement and air transfer, but also to increase the contact area of the cores with the coating material. Fig :- Side-vented pan of Hostetler 22 A.B.C.P.Sangli

23. IMPROVEMENT IN THE DRYING EFFICIENCY: Generally, the energy required for evaporating the moisture from the coating layers is derived from the drying air. The duration of the coating process as well as the quality of the end product thus crucially depend on the efficiency of heat and mass transfer. Increasing the heat and mass transfer either directly (for example by increasing temperature and rotation 23 A.B.C.P.Sangli

24. speed or implementation of perforations) or indirectly by improving the drying air supply can improve drying efficiency. With the conventional drying method, the drying air is blown across the surface of the core bed. As only the surface of the core bed is exposed to the drying air, insufficient drying of core materials and impaired spraying processes might occur. Hence, different drying gadgets have been developed, of which the two conventional ones are the immersion tube and the immersion sword. 24 A.B.C.P.Sangli

25. IMMERSION SWORD SYSTEM: IMMERSION SWORD SYSTEM With the immersion sword system, drying air is introduced through a perforated metal sword device that is immersed in the tablet bed. The drying air flows upward from the sword through the bed. Since the air is more intimately mixed with the wetted tablets, a more efficient drying environment is provided. As shown in figure. 25 A.B.C.P.Sangli

26. IMMERSION TUBE SYSTEM: In this type of system the immersed tube delivers the heated air, and a spray nozzle is built in the tip of the tube. During this operation , the coating solution is applied simultaneously with the heated air from the immersed tube . The drying air flows upward through the tablet bed and is exhausted by a conventional duct. 26 A.B.C.P.Sangli

27. Both the immersion sword and immersion tube systems are adaptable to conventional coating pans . Relatively rapid processing times have been reported for both film and sugar coating with this system. The centrifugal force first pushes the particles outwards from the centre to the pan wall and then upwards following the curve of the wall. Particles then drop down back into the middle of the container due to gravity. Usually, such equipments include a return device at the upper part of the wall which assists the feed material to roll back into the container. 27 A.B.C.P.Sangli

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29. Pan Coaters Rotating on Vertical Axis: Pan Coaters Rotating on Vertical Axis Represents another approach towards the improvement of pan coating. Designed to overcome the problem of mechanical abrasion of cores encountered in horizontally rotating pans with baffles or blades. Generally, in coaters that rotate around vertical axes, the feed material to be coated is placed in a container which is moved by a driving motor. This causes the circulation of particles on the axis of rotation. 29 A.B.C.P.Sangli

30. The centrifugal force first pushes the particles outwards from the centre to the pan wall and then upwards following the curve of the wall. Particles then drop down back into the middle of the container due to gravity. Usually, such equipments include a return device at the upper part of the wall which assists the feed material to roll back into the container. 30 A.B.C.P.Sangli

31. PERFORATED PAN SYSTEM: In Accela-cota and Hi-coater systems, drying air is directed into the drum, is then passed through the tablet bed, and is exhausted through perforation in the drum. . Hi-coater: Hi-coater Stretched" Design Provides Shorter Process Times An increased spray zone is accomplished by lengthening the coating pan while maintaining the same diameter Fully Perforated or Integrated Plenum 31 A.B.C.P.Sangli

32. Driacoater : The Driacoater introduces drying air through hollow perforated ribs located on inside periphery of the drum. As coating pan rotates the ribs dip into the tablet bed, and dying air passes through and fluidizes the tablet bed. Air is exhausted from back of the pan . 32 A.B.C.P.Sangli

33. For hard sugar coating , DRIACOATERS with perforated multisided drums are used. The machines are capable to handle sugar and sugar free solutions, ( Sorbitol , Xylitol , Malitol , Isomalt , etc.), glazing and polishing solutions as well as aqueous suspensions. Automatic loading and unloading, inside pan cleaning and fully automatic process capabilities characterize this DRIACOATER with batch sizes from 625 liters to 3750 liters. 33 A.B.C.P.Sangli

34. Complete production units including Dosing and spraying systems for solutions, flavor and polishing. Dosing/distribution for solid powdery materials. Supply and exhaust air installations with air conditioning 34 A.B.C.P.Sangli

35. FLUIDIZED BED SYSTEM: Process advantages Uniform, continuous product coating. Aqueous or organic coatings can be applied. Coating and drying take place in one machine. In terms of Total Containment, the coating process and the filling and emptying of the machine can be carried out in complete isolation and without product spreading into the environment. When using organic solvents, the process machines can also be made inert and used with a solvent recovery system. 35 A.B.C.P.Sangli

36. Principle of operation  With fluid bed coating, particles are fluidized and the coating fluid sprayed on and dried. Small droplets and a low viscosity of the spray medium ensure an even product coating . Glatt offers Batch Fluid Bed Systems in different batch sizes with: Top Spray Coating Bottom Spray Coating ( Wurster Coating) Tangential Spray Coating (Rotor Pellet Coating) 36 A.B.C.P.Sangli

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38. Top Spray Coating This process is used for general coatings right up to enteric coating. With top spray coating in the fluid bed (batch and continuous), particles are fluidized in the flow of heated air, which is introduced into the product container via a base plate. The coating liquid is sprayed into the fluid bed from above against the air flow (countercurrent) by means of a nozzle. Drying takes place as the particles continue to move upwards in the air flow. Small droplets and a low viscosity of the spray medium ensure that the distribution is uniform. Coating in the continuous fluid bed is particularly suitable for protective coatings/ colour coatings where the product throughput rates are high. 38 A.B.C.P.Sangli

39. The product is continuously fed into one side of the machine and is transported onwards via the sieve bottom by means of the air flow. Depending on the application, the system is sub-divided into pre-heating zones, spray zones and drying zones. The dry, coated particles are continuously extracted. 39 A.B.C.P.Sangli

40. Bottom Spray Coating (Continuous fluid bed) Particularly suitable for protective coatings/ colour coatings where the product throughput rates are high. The product is continuously fed into one side of the machine and is transported onwards via the sieve bottom by means of the air flow. 40 A.B.C.P.Sangli

41. Depending on the application, the system is sub-divided into pre-heating zones, spray zones and drying zones whereby spraying can take place from below in the form of a bottom spray. The dry, coated particles are continuously extracted. 41 A.B.C.P.Sangli

42. Tangential Spray Coating (Rotor pellet coating) Ideal for coatings with high solid content. The product is set into a spiral motion by means of a rotating base plate, which has air fed into the powder bed at its edge. The spray nozzle is arranged tangentially to the rotor disc and also sprays concurrently into the powder bed. 42 A.B.C.P.Sangli

43. Very thick film layers can be applied by means of the rotor method. 43 A.B.C.P.Sangli

44. Spouted Bed Coaters: An effective alternative to fluidized beds for handling coarse particles over 2 mm diameter. Main parts of a spouted bed equipment with different processing systems Main parts of spouted bed equipment can be defined as, Air/gas inlet chamber Opening device Process chamber Spraying system Exhaust chamber. 44 A.B.C.P.Sangli

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46. The air/gas inlet chamber comprises the lower part of the apparatus and - like in the fluidized bed system – can be implemented in single or divided form. Unlike the fluidized bed processes, the spouting air/gas does not enter the processing chamber through the air distribution base plate, but through an opening device with relatively high velocities, typically between 1 and 30 meters/second. 46 A.B.C.P.Sangli

47. CONCLUSION: Coating technology, e.g. film coating technology is now a days very important in the field of pharmacy particularly in formulation development. Process parameters and coating composition play an important role in coating of tablets. Therefore, to get good final quality of coated tablets, it is necessary to optimize the parameters. 47 A.B.C.P.Sangli

48. Reference “Introduction to Pharmaceutical Coating”. TIPT Hand Notes, Toronto Institute of Pharmaceutical Technology 2013–2014, pp. 2–27. “Introduction to Pharmaceutical Coating”. TIPT Hand Notes, Toronto Institute of Pharmaceutical Technology 2013–2014, pp. 2–27. Hogan J. Pharmaceutical Coating Technology. Taylor and Francis Ltd. 1998, pp. 6–52. https://www.lfatabletpresses.com/articles/types-tablet-coating-machines 48 A.B.C.P.Sangli

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