Tablet Coating Machine: Working, Types & Applications

Have you ever wondered how tablets get their shiny and unique color? Well, that's because of a tablet coating machine. These machines apply a protective, often glossy coat on the tablets to mask their odors, protect the active drug ingredient, and control drug release.

If you’re in the pharmaceutical industry looking to explore more about tablet coating machines, you are at the right place. In this article, we will walk you through the basic principles, types, and applications of these machines.

What is the Tablet Coating Machine?

Typically, tablet coating machines are mechanical devices that apply a thin, uniform film layer of material to the surface of a tablet. This layer protects the active drug ingredients against external environmental influences like moisture and light, ensuring they remain potent.

More and more pharmaceutical companies now use these tablet coating devices, and that's why their market is expected to hit $4.1 billion by 2031. Some popular types of tablet coating processes are:

• Film tablet coating
• Sugar coating
• Enteric coating
• Dip coating
• Organic coating
• Electrostatic coating
• Vacuum film coating
• Aqueous film coating

What is the Basic Principle of Tablet Coating?

The typical tablet coating principle is based on the fluidization of the tablet bed. So here's how it works: The tablet coating machine sprays a coating solution onto the compressed tablets placed in a bed.

This bed moves in different directions, both horizontally and vertically, so the tablet gets an even coat. At the same time, heated air is blown on the coat to dry it and facilitate solvent evaporation.

tablet coating machine working principle

To help you better understand the whole workings of a tablet coating machine, here's a step-by-step working guide:

1. The process begins by identifying the right batch of tablets and coating solution for consistent coat quality.
2. Tablets are then loaded onto a coating pan or bed manually or using a hopper. It's preheated to ensure there's no moisture and the surface is ready for coat adhesion. 
3. A spraying gun or nozzle atomizes the coating solution into a fine mist, which is then applied to the tablet using calibrated equipment.
4. The heated air then flows through the tablet bed to dry the coating and evaporate all solvents. Both spraying and drying are repeated until you achieve the desired coat thickness. 
5. The coating pan or bed continues to rotate until the tablets cool down and the coating hardens. 
6. Tablets are then discharged manually or via a conveyor system for further processing and packaging. 

What are the Three Types of Tablet Coating Machines?

Now that you are aware of the working process of a tablet coating machine let's discuss the three main types of these machines: 

Standard Coating Pan 

The standard coating pan is quite simple and efficient in coating tablets. It has a round steel pan that's set up on a stand in an angular position at 30 to 45 degrees. 

The diameter of the coating pan varies from 15 cm to 200 cm, and you can pick the one that suits your needs. Tablets are placed on the pan, which is rotated on a horizontal axis by an electric motor.

It has a traditional air-atomized spray system that applies a coating solution to the tablet, while the built-in heating system blows dry air on the tablet to dry the coat. This hot air is then released through the exhaust present on the pan.

Perforated Coating System

A perforated coating system has a fully or partially perforated drum. Tablets are placed on the drum that spins in a horizontal direction in an enclosed housing to coat tablets.

There are spraying nozzles that quickly apply coating solution to the surface of the rotating bed. The overall drying and coating process in a perforated coating system is quite quick, streamlining tablet coating and delivery.

Fluidized or Air Bed Coating System

The key components of a fluidized coating system include a fluidized bed chamber, a spray nozzle, a heating system, and an exhaust system for solvent evaporation.

In this system, the tablets are suspended in a stream of heated air which causes them to move and behave like a fluid. Sometimes a small column is placed that controls the movement of tablets in the chamber or main column.

Coating solutions are applied continuously to tablets using a nozzle spray that's located above the chamber bed, coating all tablets evenly.

Tablet Coating Machine Applications

Tablet coating machines are used for various purposes, ranging from giving the tablet a unique color to masking its odor. Let's discuss them in detail:

• Mask Tablet Odor: Tablets have a very bad odor that can put people off, and they may avoid medications, worsening their condition. However, tablet coating machines apply special coats on the surface of the drug that mask unpleasant odors, making the drug more acceptable and easier to take.
• Protects Against External Elements: Tablets contain active ingredients that help your immune system fight against a specific disease. Exposure to elements like air, moisture, and light can degrade the functioning of the active ingredients. But there's nothing to worry about as drug coating machines apply a protective layer on the drug, shielding it against all these external elements and preserving its effectiveness.
• Gives the Tablet a Pleasing Appearance: Colourless and weird-looking drugs can reduce their acceptance among kids. Nonetheless, tablet coating devices give these tablets a colorful and glossy outlook that makes them more attractive and easy to swallow for patients of all ages.
• Controlled Drug Release: Tablet coating equipment also ensures controlled drug release. For instance, coatings like the Enteric Coating are applied on certain medications to shield them against stomach acid while ensuring optimal absorption in the intestine.

Conclusion

Tablet coating machines are used by almost all pharmaceutical companies nowadays. If you are also considering getting this equipment for your business, you should pay attention to the cost, type of machine, and safety and compliance standards. Having this device will ensure that you deliver high-quality yet visually appealing drugs to customers quickly.