A tablet coating machine applies a coating to tablets or other solid dosage forms. The coating can improve appearance, mask bad tastes, and protect the drug from moisture or light.
Some coatings also control how the drug works in the body. For example, enteric coatings protect a tablet from stomach acid. Sustained-release coatings help release the drug over a longer period.
There are three main types of tablet coating machines:
1. Standard or conventional coating pan
2. Perforated pan coating machine
3. Fluid-bed or air-suspension coating machine
For most conventional tablets, a pan coating machine is the normal choice. Fluid-bed coating is mainly used for special products.
Conventional tablets in the 8–15 mm range are usually better suited to pan coating machines. Smaller products, such as 2–3 mm mini-tablets, may also be coated in a fluid-bed or Wurster coater. Some mini-tablets can be processed in either system.
Overview of Tablet Coating Machine Types
1. Standard Coating Pan
The standard coating pan, also known as a simple coating pan, is a traditional design used for pharmaceutical tablet coating.
It consists of an inclined, round metal pan that rotates on its axis. The tablets tumble inside the rotating pan, while the coating solution is applied by hand or with a spray gun. Hot air is then fed into the pan to remove surface moisture and dry the coating. This process can produce finished products such as sugar-coated tablets.
Features
- The round metal pan is usually available in diameters from about 200 to 1250 mm (7.9–49.2 inches).
- The pan angle can be adjusted from 15° to 45°.
- Batch capacity ranges from 1 kg to 150 kg/batch. This covers lab work, pilot production, and larger batches.
- The machine uses a stable, low-temperature hot-air system. This is suitable for sugar coating, film coating, and other common coating processes. The lower temperature also helps protect heat-sensitive materials.
Applications
The standard coating pan is closely linked to traditional sugar coating. It is useful when several coating layers need to build up on the tablet surface.
- Small-batch production
- Laboratory coating
- Pharmaceutical sugar coating
- Confectionery coating
- Chocolate coating
- Processes that do not need high drying capacity
The pan wall is not perforated. Because of this, most of the drying air reaches only the exposed surface of the tablet bed.
This gives the standard pan lower heat and moisture transfer efficiency than a modern perforated coating drum.
2. Perforated Pan Coating Machine
The perforated pan coating machine is one of the most important and widely used types of equipment for modern tablet film coating.
It uses a horizontal perforated drum inside a closed housing. The coating process combines spraying, mixing, and drying.
As the drum rotates, the tablets move and form a continuous tablet bed. Spray guns break the coating liquid into fine droplets of about 15–60 μm and spray them onto the tablet surface.
Clean hot air then passes through the holes in the drum and through the tablet bed. This helps the coating spread, dry, and form a stable film.
This through-bed airflow is one of the main reasons for the high drying efficiency of a perforated pan coater. It is also a key difference between a perforated pan and a standard solid coating pan.
Features
- High coating efficiency: The machine is suitable for medium and large batches. It can complete tablet coating in a stable and efficient way.
- Stable film quality: The tablets move evenly through the spray area. This helps the coating reach more tablet surfaces and improves film consistency.
- High level of automatic control: The system can control drum speed, spray rate, temperature, and airflow. This makes it easier to repeat the same process from batch to batch.
Applications
- Aqueous film coating
- Organic solvent-based film coating
- Sugar coating
- Enteric coating
- Color coating
- Sustained-release coating
- Controlled-release coating
LTPM CHINA’s automatic coating machines feature digital control of spray rate, inlet air temperature, and drum speed—ensuring consistent coating thickness and minimal manual intervention.
3. Fluidized Bed/Air Suspension System
A fluid-bed coating machine uses upward airflow to suspend and move the product.
The coating process is based on the fluidization principle: upward-moving air suspends the materials, while a central partition creates a controlled circulation path that allows the materials to pass repeatedly through the spray zone and gradually build up a uniform coating layer.
Fluid-bed systems commonly use three spray methods:
Top Spray: Widely used for granulation and some coating processes.
Bottom Spray / Wurster: Particularly suitable for coating pellets and other small particles.
Tangential or Rotor Spray: Commonly used for pellet formation, layering, and coating.
Fluid-bed coating works well with pellets, granules, beads, and mini-tablets. Larger tablets need more airflow to stay suspended. This increases the risk of collision, abrasion, edge wear, and breakage. For this reason, most conventional large tablets are coated in perforated pan machines. Fluid-bed systems are mainly used for pellets, granules, beads, and selected mini-tablets.
How to Choose the Right Coating Equipment
The right tablet coating equipment depends mainly on three things:
- The product
- The coating process
- The required batch size
First, choose the machine type based on the dosage form and coating process. Then choose the capacity and machine setup based on production needs.
Choose a standard coating pan when the process mainly uses traditional sugar coating, the batch size is small, or high drying capacity is not needed.
Choose a perforated pan coating machine for most conventional tablets. It is especially suitable for film coating, enteric coating, protective coating, and functional coating in commercial production.
Choose a fluid-bed or Wurster system for pellets, beads, granules, other small particles, and suitable mini-tablets.
After you choose the machine type, you can select the right model based on the required batch capacity.
If you still have questions about machine selection, feel free to contact us. We are available 24 hours a day.
Frequently Asked Questions
What Is the Difference Between a Coating Pan and a Perforated Coating Pan?
A standard coating pan has a largely non-perforated wall, so drying air mainly contacts the exposed surface of the tablet bed.
A perforated pan allows hot air to pass through the drum and tablet bed. This gives faster drying and better process control.
Is a Fluid-Bed Coater Better Than a Perforated Pan Coater?
No machine is better for every product. They are designed for different product characteristics.
- A perforated pan coater is designed for conventional tablet coating and is suitable for most full-size tablets.
- A fluid-bed coater works better with pellets and other small particles. It is also suitable for some mini-tablets.
The right choice depends on the size, shape, strength, and coating needs of the product.
Are Film Coating, Sugar Coating, and Enteric Coating Different Types of Coating Machines?
No. They are different coating processes, not different machine types.
The same perforated pan coating machine can be used for film coating, sugar coating, enteric coating, or functional coating.
The main changes are the coating formulation and process settings. These can include spray rate, temperature, airflow, drum speed, and drying conditions.
The machine must also be cleaned when changing products or coating materials. Depending on the machine setup, cleaning can be done manually or with a CIP/WIP system.
If you need several coating processes on one machine, tell the manufacturer before you order. The spray system, air system, controls, and cleaning setup can then be matched to your needs.
Can the Same Type of Tablet Coating Machine Be Used from Lab to Production Scale?
Yes.
Perforated pan coating machines are available in many sizes. Small models can be used for R&D work, while large machines can handle commercial production.
However, you cannot simply copy the same settings from a small machine to a large one.
Drum size, batch load, airflow, spray coverage, and tablet movement all change as the machine gets larger. The process must be adjusted during scale-up.
What Installation, Training, and After-Sales Support Is Available?
Tablet coating machine support can include installation, commissioning, operator training, maintenance training, spare parts, warranty service, and technical support.
LTPM has more than 20 years of experience in pharmaceutical equipment manufacturing. Our machines have been supplied to customers in more than 30 countries.
Our tablet coating machines come with a 5-year warranty. Installation, commissioning, training, and technical support can also be arranged based on project needs.
Contact us with your tablet type, required batch capacity, and coating process. We can help you select a suitable tablet coating machine.