Soft Gelatin Capsules Manufacturing Process: The Complete Guide

Today, I am going to introduce you to yet another important procedure in the capsule filling industry called soft gelatin capsules manufacturing process.

It is a simple process that involves 4 critical stages.

At every stage, there are a number of procedures that you must get right to ensure the final product meets high-quality standards.

Obviously, it is impossible to think of how to make soft gelatin capsules if you do not have the right encapsulation machine.

Here is a simple guide that will help you choose the best Softgel encapsulation machine.

Step #1: Preparing Gelatin

Normally, this forms the “container” that will hold the soft gelatin capsule ingredients. This is why you need to choose high quality materials that will be the shell of these capsules.

Besides, it will protect the content of capsules from the effects of external environment. These may include moisture/humidity, fluctuating heat/temperature, acidity, etc.

So, what do you need to prepare gelatin?

Generally, the key composition of this capsule shell includes:

• Gelatin
• Plasticizer
• Water
• Other ingredients such as coloring, opacifying agents, sugars, etc.

In the soft gelatin capsules manufacturing process, you must mix all these ingredients to get a suitable shell for the capsules.

Let’s quickly go over each of these ingredients:

What is Gelatin?

The use of gelatin to make soft capsules has been approved by both the United States Pharmacopoeia (USP) and the European Pharmacopoeia (PhEur). It is by far one of the most popular materials in the pharmaceutical and food processing industries.

In most cases, you can obtain gelatin through a partial hydrolysis of collagen. You can derive it from animal bones, skin or connective tissues.

Whenever you are sourcing for gelatin to make capsules, it should meet at least the following criteria:

• Gelatin strength (Bloom) should vary between 150 and 200; this is basically the measure of cohesive strength of the material’s cross-linkage.
• Viscosity may range from 25 to 45milli poise. You can determine this depending on 60°C/6–23% w/w in water).
• A well-defined gelatin particle size
• Broader molecular weight distribution

Below is an example of the various types of gelatins you can use in Softgel capsules manufacturing process.

Water in Gelatin

The quantity of water varies depending on the viscosity of gelatin. On average, the quantity is 45% w/w.

Plasticizer in Soft Gelatin

It is the plasticizer that makes the soft gelatin elastic and pliable. Some of the most common plasticizers are sorbitol and glycerin.

Under normal circumstances, the ratio may range between 0.3 and 1.8. This will depend on the strength of the capsule shell.

Other Ingredients of the Soft Gelatin Shells

You can opt for a synthetic or natural color. This will depend on the desired appearance of the soft gelatin capsules.

Another additional ingredient is the opacifier such as titanium dioxide. They produce opaque shells to prevent possible photo degradation of certain contents of the capsules.

Once you choose appropriate ingredients for the soft gelatin capsules, it is now time to begin the process.

Here is exactly what you should do:

Choose a Suitable Gelatin Melting Tank

In the soft gelatin capsules manufacturing process, choosing the best reactor will produce high quality and reliable shells. The gelatin melting system heats, melts and mixes all ingredients.

Whenever you are choosing this tank, it is important to consider its technical specifications such as power consumption, capacity, temperature, mixing speed and dimensions, among other aspects.

Furthermore, the design should prevent unnecessary heat loss. It is for this reason that most gelatin melting tanks feature thermal jackets.

Besides, they have a torque turbine mixture. It stirs and mixes the content under vacuum.

Of course, as the heating process continues, water tends to evaporate.

Melt & Heat Gelatin Ingredients Until It Turns to Molten Liquid Mass

In most cases, the heating and mixing of gelatin ingredients can take at least 3 hours. This will depend on the efficiency of the gelatin heating and melting tank.

During this process, all the ingredients of the soft gelatin will mix evenly. This will result in a molten liquid mass.

Once the gelatin material is ready, the encapsulation process can now begin.

However, this does not imply that you should allow the gelatin to cool. It should remain warm to ensure the gelatin is in liquid state.

This is because it is only when gelatin is in liquid state that it can flow to the spreader box. That is, it will leave the spreader box through a controlled gap to the cooling drum.

This will then result in a thin gelatin ribbon.

Next, you should prepare the fill material.

Here is how to go about it:

Step #2: Prepare Fill Material

This is the material you intend to enclose with the gelatin.

In the soft gelatin capsules manufacturing process, the fill material for Softgel may be in the form of:

• Liquid
• Semi-solid solution
• Suspension

While preparing the fill material, it is important to ensure that the final product is homogenous. This will ensure that all the vital components are in each soft gelatin capsule.

Depending on the type of ingredients, you may require many pharmaceutical equipment and accessories. These may range from hammer mills, fluid bed processors, pharma ovens, bins and drums, just to mention a few.

All you need are machines and equipment that will help you to make the right fill material.

Remember, the process of making an appropriate fill material may vary broadly depending on their specific ingredients. For example, making oil mixtures is simple and easy to formulate unlike the pastes.

Again, it is important to ensure that the fill material you intend to use in the soft gelatin capsules manufacturing process meets the following criteria:

• Can guarantee overall stability of all its individual elements, including active ingredients.
• Increase bioavailability, which forms a key aspect why soft gelatins are popular
• It should guarantee safe and efficient soft gelatin filling process
• Fully filled Softgel capsule must remain stable

With all these in mind, I am sure you will have the best fill material for manufacturing soft gelatin capsules.

Now that you have the soft gelatin and fill material, it is time to move to another critical step in the Softgel capsules manufacturing process.

This is the:

Step#3: Begin the Encapsulation Process

First, even before we discuss how this process takes place, it is worth mentioning that you need to choose the right encapsulation machine.

That is, a Softgel encapsulation machine that:

• Conforms to the cGMP and CE standards
• Meets the right production criteria; there are the low, medium and high production machines. For instance, for low production processes, you should go for R&D Softgel encapsulation machines.
• Has the right features and specifications
• Is easy to operate, maintain and change the tooling system
• Has robust automation systems and control panel

In short, you can review my simple guide on Ultimate Buying Guide for Softgel Encapsulation Machine.

With all these in mind, now let’s come back to the actual soft gelatin capsules encapsulation process.

Ideally, it is during the encapsulation stage that both the fill material and gelatin shell come together to form capsules.

Don’t worry, I will explain how this process works shortly. Before that, I want you to review this image showing critical process in the soft gelatin capsules encapsulation process.

Movement of Gelatin Shell to the Tooling System

At this stage, the warm gelatin material will flow from the gelatin tank to the spreader box (see image above). It will then spread over a revolving cooling drum to form a solid ribbon of gel.

That is, a warm gelatin that is in liquid state, changes to a solid ribbon.  This change in state is due to the cooling effect of the drum.

In most cases, the design of these soft gelatin capsule filling machines use air to achieve a suitable cooling effect. The key parameters of air include:

• Cubic foot per minute (CFM) of air
• Temperature
• Relative humidity

Remember, the design of Softgel encapsulation machine is such that, all the components that are on the left side of the machine are also on the right section. That is, they both have warm gelatin flowing via a spreader box, cooling drum and to the tooling system.

At any given time, the two solid ribbons of gelatin should reach the tooling system at the same time.

How Fill Material Moves to the Tooling System

After preparing the material, you will fill the hopper or product tank.

From the tank, a positive displacement pump directs the fill material to the heated injection wedge via some tubes.

This wedge rests between the two die rollers as you can see in the image above.

Actual Process in Soft Gelatin Capsules Manufacturing Process

It is this wedge that will inject the fill material into the die cavities. This takes place as the left and right gelatin ribbons are fed into the die roller system.

In short, these processes take place simultaneously, such that the machine feeds the gelatin ribbon as the wedge injects fill material. At the same time, the die system cuts and hermetically seals the two halves of the gelatin ribbons together.

It is important to remember that the die rolls determine both shape and size of the capsules. Therefore, you should choose the right die cavity depending on the type of Softgel capsules you need.

Well, there are many ways of producing soft gelatin capsules:

• Rotary die process
• Plate process
• Reciprocating die
• Accogel machine

The choice of a particular soft gelatin capsules manufacturing process will depend on the availability of the machine and production needs.

So far, the plate and rotary die process are the most common processes of manufacturing Softgel capsules.

The soft gelatin manufacturing process described above is basically the rotary die process. It is by far the most popular soft gelatin capsule filling process.

On the other hand, the plate technique is also a simple process that involves the following:

• Place a gelatin sheet on a die plate that has numerous die pockets
• A vacuum draws gelatin sheets into the die pockets
• Die pockets are then filled with material fill
• Place a second gelatin sheet on the filled die pockets and sandwich using die press. It is at this stage that the soft gelatin capsules are formed and cut.

In short, choosing a specific soft gelatin manufacturing technique will depend on your production needs.

By the end of the process, the soft gelatin capsules will move to the conveyor belt for further processing. This is because these capsules are too moist and soft thus they may not withstand certain environmental conditions.

Besides, there is need to inspect the soft gelatin capsules to ensure they contain the right quantity of fill material.

So, let’s see how to go about these processes:

Step #4: Further Processing of Filled Soft Gelatin Capsules

This is also a critical stage in the soft gelatin capsules manufacturing process. In most cases, it involves the following important procedures:

• Drying soft gelatin capsules
• Quality control in soft gelatin capsules manufacturing process
• Polishing & packaging of soft gelatin capsules

Now, let’s quickly go over each of these processes:

Drying Soft Gelatin Capsules

It is this process that will remove any excess moisture in the soft gelatin capsules. In most cases, the drying time will depend on the number and size of capsules.

Normally, there are two stages when it comes to drying soft gelatin capsules:

1. Using Tumble Dryer

You will find that most designs of soft gelatin capsule filling machines are such that the conveyer belts are linked directly to the tumble dryer. That is, once the soft gel capsules leave the die system, they move directly to the tumble dryer.

The tumble dryer will remover about ¼ of the amount of water present in the Softgel capsules.

2. Drying Soft Gelatin Capsules in Stackable Trays

Once the capsules leave the tumble dryer, you will spread them on the drying trays, then place them in a tunnel or drying room.

In the drying tunnel, air flows at a predetermined velocity with known temperature and humidity, thus, causing the drying effect.

Normally, the drying process in the two stages can be 24 hours or more, depending on the water content in the Softgel capsules.

This step can increase the soft gelatin capsules manufacturing process costs significantly if not designed properly. It is for this reason that you will find most Softgel capsules filling machines incorporating both the dehumidifiers and refrigeration.

After drying the soft gelatin capsules, it is now time to inspect the soft gelatin capsules.

Quality Control in Soft Gelatin Capsules Manufacturing Process

Quality control (QC) is an important process in any capsule filling process. It is at this point that you can detect and remove damaged soft gelatin capsules.

You can use a Softgel capsule sorting machine. This will eliminate any possible errors that are common to the manual capsule sorting processes.

At SaintyCo, we have a range of automatic capsule filling, processing and inspection equipment. You can have a quick overview in the video below:

During the QC stage, you should focus on the following:

• Eliminating damaged, broken or misshaped Softgel capsules
• Verifying capsule appearance, weight, content uniformity, etc.
• Conducting microbiological testing
• Determining the shell moisture level, thickness, weight and sealing mechanism

Once your soft gelatin capsules meet a specific criterion, it is now time to move to the last stage of the manufacturing process.

Polishing & Packaging of Soft Gelatin Capsules

At this stage of the soft gelatin capsules manufacturing process, you will clean and remove any material on the surface of the capsules. That is, the process aims at ensuring the Softgel capsules have the right color and texture.

The process may involve tumbling or using a solvent to wash the surface. Remember, this will depend on the design of the Softgel polishing machine.

Apart from polishing, you may wish to customize Softgel capsules by putting a unique mark on the shell. Well, here is a solution for you.

You can try this Softgel printing machine. It can print any shape of Softgel capsules.

Once you have done all these processes, you can use a suitable pharmaceutical equipment and machinery to pack the Softgel capsules

Of course, the packaging must protect the Softgel capsules from damage and guarantee the stability of its ingredients or active compounds/elements.

Conclusion

As you can see, it is quite evident that the soft gelatin capsules manufacturing process is simple and straightforward. All you need is a high quality Softgel encapsulation machine and auxiliary support equipment.

At SaintyCo, we design, manufacture and supply a wide range of pharmaceutical and packaging equipment.

For inquiries or free consultation, you can contact us today.

References

• Softgel (Soft Gelatin) Capsules – Source: Abhishek Raj from amol pharmaceuticals
• Soft Gelatin Manufacturing Process – Source: Google Patents
• Capsules – Source: SRM University