Tablet Coating Machine: The Ultimate FAQ Guide

Tablet coating requires cGMP compliant, accurate and reliable machine that can boost your tablet compression business.

You can only choose the best tablet coating machine by knowing the working principle, features, specification, benefits, possible drawbacks, etc.

And, this guide covers all the vital aspects of tablet coating equipment you should know:

What is Table Coating Machine?

A tablet coating equipment is a machine that adds a thin layer on the outer side of fully compressed pharmaceutical tablets.

The coating is usually a thin-polymer based layer.

A good example is the SaintyCo Lab Tablet Coater.

 Lab tablet coater

What are the Types of Tablet Coating Machines available

The following are the main types of coating machines available:

1. Standard Coating Pan

Sugar coating pan

This is a common tablet coating machine in the pharmaceutical industry.

It consists of a circular metal with a diameter of between 6 to 80 inches.

The pan has a slight tilt of 45°C to the benchtop.

It also consists of an electric motor which horizontally rotates a circular metal pan to its axis.

The conventional pan also consists of a pan system with an air inlet supply.

When using this machine, you need to ensure that there is no chemical reaction between the air temperature and the tablets.

The limitation of this machine is the improper balancing of the exhaust air and inlet air.

This has the effect of complicating the entire process.

There are three ways of improving the efficiency of this machine.

That is, Immersion tube system, immersion sword, and baffled pan and diffuser.

• Perforated Coating Pan

 Perforated film coating system

This type of machine consists of either a full or partially perforated drum.

This machine features a horizontal axis rotation of the drum.

There is an enclosure of the drum in housing which consists of different spray nozzles.

The function of these spray nozzles is the atomization of the coating solution.

The machine features an efficient drying system and a high capacity for tablet coating.

• Fluidized Bed Coater

Fluid bed granulator and coater

This type of machine works by fluidizing the particles, followed by the spraying of the coating fluid.

There are three types of spraying in this machine.

That is Bottom Spray coating, Top Spray coating and tangential coating.

Why is Tablet Coating done?

The importance of carrying out tablet coating include:

• It enhances its appearance which makes them attractive and easy to consume.

• Minimizes the unpleasant colour, odour or taste that is associated with drugs

• Facilitates easy identification of drugs

• Reduces drug degradation due to a change in environmental factors such as temperature

• Facilitates the blistering process

How do you Evaluate Tablet Coating Machine for Pharmaceutical Use?

Evaluation of Tablet Coating machine for Pharmaceutical use should consider the following:

• A cGMP Compliant Design

A table coating machine for pharmaceutical use should adhere to Current Good Manufacturing Practice standards.

This sets the standards for conforming to the U>S regulations on Food and Drug Administration (FDA).

cGMP Compliant Design ensures you have a quality machine for your use.

• Type of Material

A pharmaceutical tablet coating machine should have a corrosion-resistant material.

Such materials should adhere to AISI 316 for the inner sections and AISI 304 for the outer sections.

The outer section includes the electrical panel, wheel joints, and the outer casing.

The inner section includes the coating drums, spraying device, and coating substrate container.

• The Ergonomic Design of the Tablet Coater

The Ergonomic Design of the tablet coater helps in enhancing reliability and performance.

Such a design should have a wheel for easy movement.

This helps in minimizing the occurrence of accidents or preventable breakdowns.

You, therefore, have an assurance of continuous tablet coating of your machine.

What are the Advantages of Coating Tablets?

The advantages of tablet coating include:

 Coated tablets

• Enhances Tablet’s Stability

Tablet coating enhances the tablet’s stability.

This is by ensuring that it is water-resistant and it does not react with the external environment.

This increases its lifespan and its usability.

• Tablet Lifespan

Tablet coating increases the of the tablets by minimizing environmental interference.

Such interference can be excess temperature or humidity which affects the quality of the tablets.

• Enhance Tablets Appeal

Tablet coating enhances the appearance of the Tablet, making it attractive.

This facilitates the usage rate since they are easily acceptable.

• Easy Identification of Tablets

Tablet coating enables one to identify a tablet easily.

This prevents the wrong usage of tablets.

• Prevents Chemical Incompatibility

Tablet coating minimizes the chances of chemical contamination when mixing with other tablets.

This increases the safety of the tablets.

How do you Choose Solvent for Coating Tablets?

You need to consider the following when selecting a solvent for Coating Tablets:

i. Environment Impact

An ideal solvent for tablet coating should not have any environmental impact.

Reaction with the environment may result in a change in the chemical properties of the tablets, which can be hazardous.

ii. Drying Rate

An effective solvent should be able to dry quickly and effectively.

This helps in minimizing the defect formation as a result of improper drying.

iii. Dispersion

The best solvent is one that easily disperses other coating solutions.

It should also be able to dissolve the polymer system.

iv. Quality Physical Properties
the ideal solvent needs to exhibit quality physical properties.

These properties include colourless, odourless, inert, and non-toxic.

What are the Disadvantages of Coating Tablets?

Yes, tablet coating has several disadvantages. These include:

• Cost

Coating tablets is an expensive process which adds to the overall cost of the tablets.

This is due to the high installation cost, the cost of materials, and the running costs, such as energy cost.

• Space

Coating tablet machines require a large space for effective operation.

This can be a challenge when there is a lack of space.

• Change in Tablet Properties

Coating tablets has the effect of changing certain properties of the tablets.

These properties include the smooth, especially when there is uneven spraying of the tablets.

Also, there can be a change in the pharmacodynamic properties of the tablets — this results in experiencing difficulties during swallowing.

• Solvent Toxicity
Tablet coating requires the use of solvents that, at times, can be hazardous and toxic for use.

Also, tablet coating can result in defects such as chipping, capping and bridging.

What are the Main Parts of Tablet Coating Machine?

The main parts of a tablet coating equipment include:

i. Automated Control System
This is the part of the tablet Coating machine that automatically controls its various functions.

Such functions include operating/running of the machine, process data display, speed, pressure, and temperature.

This helps in ensuring the efficiency of the machine.

ii. Electric Motors
Electric motors facilitate various operations of the tablet Coating Machine.

These functions include blowing air, mixing the tablets, and creating negative pressure.

Electric motors are present in different sections of the tablet coating machine.

They include a coating drum, hot air equipment, peristalsis pump and the air exhaust section.

iii. Touch Screen Operating Panel

This is that part of the machine that an operator can observe, input various control and monitor its operations.

It has a user-friendly interface for easy operation.

iv. Guide Plate

The function of a guide plate in a tablet coating machine is to allow for the smooth tumbling of the tablets.

This is essential when blowing hot air through the tablets during the drying process.

It is also important in the mixing process of the tablets.

v. Peristaltic Pump

A peristaltic pump offers constant pressure to the Tablet coating machine, thereby eliminating the need for return pipes.

It also aids in the stabilization of the atoms during the spraying process.

vi. Spraying System

The spraying system consists of the nozzle, tank, and a pump.

Its functions include the atomization stability, cleaning, and maintenance of the spraying gun and storing the tablet coating solution.

It also minimizes spraying gun plug-up and ensures even and efficient atomization.

vii. Pan Cooling Surface

The pan cooling Surface consists of an Automatic Load cell System that helps in regulating the volume of the spraying solution.

It also consists of the electronic pulse valve, a Discharging device, an Exhaust dust collector, an air heating unit, and an air distribution device.

Other parts include; a Magnetic stirrer, air pipes, and fittings, and a flexible drum filter holder.

viii. Coating Preparation Tank

This is where the preparation of the coating solution takes place.

How does Tablet Coating Machine Work?

The working of a tablet Coating machine involves the selection of suitable materials.

This is dependent on the kind of tablets that you are using and the desired final coating process.

There are criteria that you can use to select the best coating materials.

The next step is the tablet spinning.

This involves putting the tablets in a drum and rotating it inan orbital way.

It is a continuous process where the streamlined plates control most of the operations.

As the drum spins, a nozzle sprays a coating solution to the tablets.

It is an automatic process that an operator controls using the controlling system.

This helps in ensuring there are accuracy and an even spray of the tablets.

Also, the angled baffles present in the drum turn the tables sideways facilitating even spraying of the tablets.

While the spaying and rotation continue, the machine pumps hot air into the drum.

This results in the rapid coating of the solution.

The machine allows for the self-regulation of the hot air temperature that flows within it.

The reason for this excess temperature can affect the chemical composition of the tablets.

The machine also regulates the pressure within the drum in line with that of the outside environment.

After all the tablets have a uniform coating, the spinning and spraying stop, the tablets then proceed to the drying section.

Here, air flows over the tablets drying them.

There is regulation as to the volume of air that flows to ensure there is no reaction with the tablets.

Once this is over, your tablets are ready for packaging.

What is Tablet Coating Pan?

A tablet coating pan is a component of a tablet coating machine whose function involves the formation of an organic coat around a tablet.

Tablet coating pan

Which Industries use Tablet Coater Machine?

The common industries that use Tablet coating Machine are:

• Medical Industry

A tablet coating machine is common in the medical industry, especially in pharmaceutical drug manufacturing.
The function of this machine is to assist in the coating of certain tablets.

The benefits of coating these tablets are to increase their appeal, taste and improve their colours.

Users of such drugs find it easy due to their coating features.

• Cosmetic Industry

Certain cosmetic products utilize a table coater machine in their manufacturing process.

Here, they add colour and stability properties to the tablets.

They increase the eye appeal of these products, which increases their sales.

Tablet Coater should Conform to which Quality Standards?

A tablet coater should conform to the following Quality Standards:

• FDA license

• The system should be GMP certified.

• It should also have ISO 9001: 2000 certification.

• Halal and Kosher certification.

Which Parameters Determine the Efficiency of Tablet Coating Process?

The main parameters that determine the efficiency of tablet coating processes include:

Tablet coating chamber

• Air Capacity

Air is a vital element when it comes to the drying process of your coating tablets.

Sufficient drying will prevent the occurrence of certain defects.

For the efficiency of a table coating process, there should be sufficient air supply within the machine.

• Coating Composition

There is a need to ensuring that you have the correct coating composition before you start the coating process.

This includes the proper mixing of the materials and regulating the pressure and temperature of the machine.

• Tablet Surface Area

The surface area of the tablet for coating determines the efficiency of the tablet coating machine.

Size should be as per the standards of the machine, which is available on the manual.

The use of inappropriate size results in tablet defects and may damage the machine system.

• Equipment Efficiency

The efficiency of the tablet coating machine determines the efficiency of the entire process.

This includes ensuring all the components are operating at the optimum level, and there is proper regulation of the processes.

How does Film Coating Tablets compare to Enteric Tablet Coating?

Enteric tablet coating is a type of film tablet coating with superior features.

The coating of an enteric tablet does not dissolve within a gastric environment.

Enteric Table Coating provides tablets for oral usage that target the upper digestive tract such as the intestines.

They also offer advanced tablets for use in drug absorption studies.

Film coating tablets easily absorb in a gastric environment.

They are ideal for use in the lower digestive tract.

Both film coating tablets and Enteric tablet coating consist of the main formulation components.

They are Polymer, Plasticizer, Colourant, Opacifier and Solvent.

What is Sugar Coating Tablets?

Sugarcoating tablets are a type of tablets that has a sucrose-based coating formulation.

The tablets pass through hot air allowing for water evaporation.

The result is a thick sugar coating on the tablets. Sugarcoating is ideal for tablets that have an unfriendly odour.

This is due to the sweet taste that the sugar coating has on the tablets.

Sugarcoating tablets go through six steps.

That is tablet core sealing, smoothing, sub-coating, colouring, polishing and printing.

How can you Conduct Validation of the Tablet Coating Machine?

You need to check on the following when validating a tablet coating machine.

Tablet coating system

• Quality

Quality validation ensures your tablet coating machine conforms to the given standards and certification.

When conduction this validation, you need to check if the machine meets all the standards available.

• Safety

The safety of the user, the machine, and the tablets are an essential validating point.

You need to check on the safety status of these parties.

The parts of the tablet coating machine should be hygienic, and there should be no reaction to the tablets.

The operator should have the necessary skills to operate the machine.

It should also consist of a procedure to follow in case of an emergency breakdown.

• Process Optimization

Your tablet coating machine should operate at an optimum level while ensuring quality production.

It important, therefore to check on the operating level of your machine and factors to consider for maximum operation.

• Cost

There should be value for the machine that you are purchasing.

You need to check on the cost of the machines and what it has to offer before buying it.

The cost should also include maintenance and the operating cost.

What are the Common Tablet Coating Defects?

The common tablet coating defects are:

• Chipping. Is when there is a dent on the coating layer, especially on the tablet edges.

• Coat cracking is a defect that causes cracking of the coat across the crown of the tablet.

• Coat flaking and Peeling occurs when there is an exposure of the Surface tablet.

This is after the peeling of the coat along the tablet edges.

• Picking is when there are isolated areas when there is a sticking of the tablets.

• Logo Bridging occurs when the coat pulls off, resulting in bridge formation across the edges.

• Roughness is when the surface becomes rough, resembling an orange skin.

This makes the tablet difficult to swallow.

• Logo in-filling results from a logo becoming eligible and distinct as you fill it using solidified foam.

• Pitting of tablets is a result of the formation of a pit on the surface core of the tablet.

• Tablet surface erosion is when there is a high friability of the tablet coat layer.
• Tablet breaking is when a tablet breaks up into two or more pieces during the coating process.

• Tablet twinning is when two or more tablets are stuck together after the coating process.
• Tablet Colour variation is when tablets from the same coating process have different colours.
• Tablet discolouration is when the tablets have dark spots after the coating process is complete.

Tablet Coater making uses which materials?

The main materials for tablet coating include:

• Polymers

Polymers are materials with a high molar mass of repeated units.

The numerous monomer molecules allow for the formation of a chain that can bind together during a chemical reaction.

It has quality characteristics that make it ideal for tablet coating.

This includes the ability to dissolve in different solvents.

They are stable against factors like light, oxygen, moisture, heat and tablets.

It is highly compatible with different additives necessary for tablet coating.

Polymers are non-toxic due to the lack of any pharmacological activity.

Polymer tablet coating produces tablets with a nice appeal that attracts the users.

Examples of polymers available for tablet coating include Carbohydrates, glycols, vinyl polymer, acrylic acid and cellulose.

• Plasticizers
Plasticizers feature low molecular weight.

They are used in addition to polymers to change the physical properties.

They are vital in the weakening of the polymer chain attraction.

They are also crucial in attracting dispersed solvent polymer spheres together during the coating process.

The use of plasticizers is to reduce the tensile strength and elastic modulus.

This, in turn, increases the coat adhesion during the coating process under different conditions.

Different plasticizers have different coat permeability due to their different physicochemical properties.

The common plasticizers available for tablet coating include glycerol, diethyl phthalate, and fractionated coconut oil.

Others include distilled acetylated mono-glycerides and Castro oil.

• Colourants

Colourants are pigments in the coating process that improve the eye appeal of the tablets.

They are also essential in the differentiation of tablets in the market.

Another role is they act as a light barrier to the tablets as they increase their opaqueness.

The main types of colourants for tablets coating include FD and C lakes, D and C lakes, and water-soluble dyes.

Water-soluble dyes are ideal since they offer better opaqueness for the light barrier.

They also have good moisture barrier characteristics.

• Solvent

The use of solvents is ideal since they don’t allow for water use due to their poor drying properties.

Solvent for Tablet coating includes methanol, ethanol and acetone.

Others include ethyl acetate, ethyl lactate, chloroform, and methylene chloride.

In addition to these materials, there are others which are optional for your tablet coating.

These include sweeteners and flavours.

Sweeteners and flavours enhance the test and remove unpleasant odour from the tablets.

How do you Troubleshoot Tablet Coating Machine?

Troubleshooting Tablet coating Machine depends on the cause of the problem.

The main troubleshooting procedures include:
Tablet coating equipment

• Colour Variation

To solve the issue of colour variation on your tablets, you need to ensure there is an even spraying and mixing of the tablets.

Alternatively, you need to change the additives and plasticizers.

• Roughness

For you to solve the issue of roughness, you need to use mild drying conditions.

You may also try using additive solvents to minimize polymer solution viscosity.

This helps in reducing the spraying rate of the solvents.

• Blistering

The solution for tablet blistering is to use a mild drying condition.

You can also use a moderate temperature during the cooling process.

• Clipping

The solution for clipping is the adjustment of the plasticizers within the coating solution.

You can also use a polymer that has a high molecular weight.

• Picking

To solve picking, you have to increase the efficiency of the drying process by increasing the temperature of the inlet air.

You can also increase the viscosity of the solution and reduce the coat solution application rate.

• Pitting

You can adjust the temperature of the air inlet temperature to solve pitting.

Also, you need to ensure that the temperature of the tablet core does not surpass the batch additive melting point.

• Cracking

You need to continuously check the efficiency of the drying process as well as optimizing the drying conditions.

• Blooming

You need to reduce the concentration and increase the plasticizers’ molecular weight

• Infill

The solution for infill is the addition of alcohol on the polymer solution.

This enhances the tablet’s solvent dispersion.

You can also usea spray nozzle which forms finer atomization.

• Blushing
You need to lower the drying temperature to solve the brushing issue for tablet coating.

This is to prevent polymer precipitation.

How do you Clean Tablet Coating Machine?

The spray nozzle is an important element when cleaning a tablet-coating machine — spraying inside the machine with a cleaning fluid help in removing any contaminants.

Cleaning is a regular process, preferably after every coating process.

This is because of the different chemicals and solvents that you are using.

What is Immediate Release Film Coating for Tablets

Immediate Release Film Coating for Tablets refers to a special type of coating for tablets.

Its function is to enhance the identity, stability, handling, and appearance of the tablets.

Immediate release film coating tablets does not have any effect on the properties of the biopharmaceutical dosage.

They also help in dissolution in the stomach when it gets into contact with available moisture.

What are the Benefits of Peristaltic Pump in Tablet Coating Machine?

The benefits of a Peristaltic Pump in a Tablet Coating Machine include:

 Tablet coater

• Constant Pressure

A Peristaltic Pump Offers constant pressure to your Tablet coating Machine.

This helps in eliminating the need for return pipes within your system.

• Atomization Stability

A Peristaltic Pump offers stability to the atomization process.

This is by ensuring there are simplicity and ease of using an automated spray.

• Prevents Contamination

A Peristaltic pump ensures there is no contamination of the contents within the tablet coating machine.

This is because you can easily clean the inner pumps of the pump, thereby eliminating contaminations.

• Efficiency

Peristaltic pump ensures there is efficiency in the operation of the tablet coating machine.

This is by ensuring there is a constant flow of solvent at any given point during the entire operating time.

• Low Maintenance Cost

It is cheaper to maintain a peristaltic pump since it does not require advanced skills.

Also, since they lack valves, glands and seals mean you can easily clean within the pump.

What is the Aqueous Sugar Film Coating System?

Aqueous Sugar film coating system is one that uses sucrose and water as the main solvent material.

It offers unique benefits over the other types of film coating systems.

For instance, they are non-toxic, which prevents environmental pollution and harmfulness to the environment.

Sucrose offers sweetness to the tablets which help in their consumption.

However, they take a lot of time for the evaporation process to complete.

Also, the aqueous sugar film coating system is not ideal for moisture-sensitive tablets.

Are there Recommended Process Parameters for Tablet Coater Machine?

Yes.

There are process parameters for the tablet Coater machine.

They include:

Coating solution pipe system

• Spray Rate

Spraying affects the moisture level of the tablets.

This affects the quality and uniformity of your coating process.

A low spray rate causes the tablets to have a brittle coat due to inappropriate wetting.

A high spray rate makes the tablets to be too wet, making them too sticky ad picky.

You, therefore, have to ensure that the spray rate is right before you start the operations.

• Air Capacity

Air is a vital element when it comes to the drying process of your coating tablets.

Sufficient drying will prevent the occurrence of certain defects.

For the efficiency of a table coating process, there should be sufficient air supply within the machine.

• Coating Composition

There is a need to ensuring that you have the correct coating composition before you start the coating process.

This includes the proper mixing of the materials and regulating the pressure and temperature of the machine.

Optimum temperature ensures the effective drying of the tablets and decreases the level of water penetration — however, excess temperature results in premature drying of the tablets which reduces their efficiency.

Also, the configuration of the spraying nozzles should adhere to the requirements of the tablet coating.

Optimum pressure minimizes the surface roughness of the tablets through the provision of a thin dense coat.

However, excess pressure results in the formation of tiny and fine droplets when the tablets dry up.

• Rotating Speed

The pan rotating speed affects the mixing properties of the tablets.

An increase in the rotation of the pan reduces thickness variation and facilitates uniformity in the coating process.

However, increasing the rotations past the optimum level leads to undesired breakage of the tablets.

• Tablet Surface Area

The surface area of the tablet for coating determines the efficiency of the tablet coating machine.

Size should be as per the standards of the machine, which is available on the manual.

The use of inappropriate size results in tablet defects and may damage the machine system.

• Equipment Efficiency

The efficiency of the tablet coating machine determines the efficiency of the entire process.

This includes ensuring all the components are operating at the optimum level, and there is proper regulation of the processes.

Which Drugs can you Coat?

You can coat water-sensitive drugs, drugs with an unpleasant odour, and one that you need to enhance its colour.

Also, drugs that you want to enhance its stability properties.

What is the difference between Aqueous Film coating and Non-Aqueous Film Coating?

An aqueous film coating is one that uses water as the solvent agent during the tablet coating process.

A Non-aqueous film coating is one that uses organic solvents in its tablet coating process.

The evaporation time for aqueous film coating is longer than that of non-aqueous tablet coating.

Due to the long-time duration, aqueous film coating can cause tablet defects.

Aqueous tablet coating is environmentally safe as it does not produce a toxic substance to the environment.

Non-aqueous tablet coating has a toxic effect on the environment.

The company should put in place ways of mitigating environmental impact

Non-aqueous tablet coating is ideal for coating tablets that are sensitive to moisture.

Aqueous tablet coating suitable for tablets that have a high chemical reactivity.

Adequate ventilation is a requirement when using a non-aqueous tablet coating method as opposed to aqueous tablet coating method.