Accela Cota coating Pan

Table Coating Machine is the mechanical device that coats the outer surface of tablet with a thin layer of coating material

• To mask the taste, odor and color of the drug.
• To provide physical and chemical protection for the drug.
• To control the release of the drug from the tablet.
• To protect the drug from gastric environment.
• To improve the pharmaceutical elegance by special color and contrasting printing.
• To incorporate another drug or formula adjuvant in the coating to avoid chemical incompatibilities.

Read about, ,

What is the definition of tablet coating machine?

What are the types and sub types of tablet coating machine?

How the tablet coating machines works?

What are the important parameters to be considered in coating machines?

What are the main coatings done in coating machine?

What are the advantages of tablet coating machines?

The principles of tablet coating are relatively simple. Tablet coating is the application of a coating composition to a moving bed of tablets with the concurrent use of heated air to facilitate evaporation of the solvents.

The distribution of the coating is done by the movement of the tablets either perpendicular or vertical to the application of the coating composition.

What are the types and sub types of tablet coating machine?

Tablet coating is done by using different varieties of coating machines. So the coating equipments are divided into following three types.

The standard coating pan

1. Pellegrini pan
2. Immersion sword system
3. Immersion tube system

The perforated coating pan

1. Accela-cota
2. Hi-coater systems
3. Driacoater
4. Glatt coater

The fluidized bed or air suspension coater

1. High pressure airless systems
2. Low pressure air atomized systems

How the tablet coating machines works?

Several companies have developed their own coating machines to accommodate their coating processes. Most of the systems are based on these three basic designs.

The standard coating pan systems:

It consists of a circular metal pan mounted somewhat angularly on the stand.

The pan is 8 to 60 inches in diameter and is rotated on its horizontal axis by a motor.

Heat air is directed into the pan and onto the tablet bed surface and is exhausted by means of the ducts positioned through the front of the pan.

Coating solution is applied on to the tablets by spraying the material on to the rotating tablet bed by using atomized systems which produce a faster and even distribution of solutions.

A significancy drying efficiency of the standard coating pan can be achieved but pellegrini, immersion sword and immersion tube systems.

a, b, c) Standard coating pans with different shapes

Simplified diagram of standard coating pans

Pellegrini pan:

This system has a baffled pan and a diffuser that distributes the drying air uniformly over the tablet bed surface.

Pellegrini pan

Immersion sword system:

In this system drying air is introduced through a perforated metal sword device that is immersed in the tablet bed.

Simplified diagram of immersion sword system

Immersion tube system:

In this the tube is immersed into the tablet bed. The tube delivers the heated air and the spray nozzle is built in the tip of the tube.

Simplified diagram of immersion tube system

The perforated pan systems:

In this all the equipment types consists of perforated or partially perforated drum that is rotated on its horizontal axis in an enclosed housing.

Accela-cota & Hi-coater systems:

In these equipments the drying air is directed into the drum, is passed through the tablet bed and is exhausted through perforations in the drum.

1. Accela-cota b) Hi-coater systems

Simplified diagrams of a) accela-cota b) Hi-coater systems

Driacoater:

In this the drying air is introduced through the hollow ribs located on the inside periphery of the drum. As the coating pan rotates the rib dip into the tablet bed and drying air passes up through and fluidized the tablet bed exhaust is from the back of the pan.

1. Driacoater systems b) simplified diagram of diracoater system

Glatt coater:

It is the latest perforated pan coater. The drying air can be directed from the inside the drum through the tablet bed and out an exhaust duct.

Alternatively with an optional split chamber plenum, drying air can be directed in the reverse manner up through the drum perforations for partial fluidization of the tablet bed.

In all these four perforated pan systems the coating solution is applied to the surface of the rotating bed of the tablets through spraying nozzles that are positioned inside the drum.

Glatt coater system

Fluidized bed or air suspension systems:

Fluidization of the tablet mass is achieved in a columnar so that more air enters the center of the column, causing the tablet to raise in the center. The movement of the tablets is upwards through the center of the chamber. There by then fall toward the chamber wall and move downward to re-enter the air stream at the bottom column is used to direct the tablet movement within the main column.

Coating solutions are continuously applied from the spray nozzles located at the bottom of the chamber and sprayed on to the top of the cascading tablet bed by nozzles located in the upper region of the chamber.

Tablet cores that are friable and prone to chipping and edge abrasion may be difficult to coat even under the optimum conditions in the fluidized bed systems, owing to the relatively rough tablet to tablet impact and tablet chamber contact.

The two types of systems used to apply a finely divided spray coating solutions or suspensions onto the tablets.

1. Fluidized bed coater b) Simplified diagram of fluidized bed coater

High pressure airless systems:

In this air less spray liquid is pumped at high pressure (250 to 3000 pounds per square inch gauge) through a small orifice (0.009 inch to 0.02 inch id) in the fluid nozzle which results in a finely divided spray.