Hard Gelatin Capsules: The Ultimate Guide

      Hard Gelatin Capsules: The Ultimate Guide

A hard gelatin capsule is a solid dosage form that is also referred to as a dry filled capsule or two-piece capsule.

                                  ( HARD GELATIN CAPSULE STRUCTURE  FIG.1 )

In the pharmaceutical industry, these capsules are mainly used to fill medicine in the form of dry powder, or tiny pellets.

Hence the dry-filled name.

They are also used to fill non-aqueous solutions, but this is in particular applications.

To know in details about the Hard Gelatin Capsules, including its manufacturing process, this article is beneficial for you.

Difference between Soft and Hard Gelatin Capsules

Well, before we get into the details, it is essential to note that there are two types of capsules on the market.

                                        (HARDGEL VS SOFTGEL CAPSULES FIG.2)

As you can already tell, the hardgel capsule is just one type.

The other type is the soft gelatin capsules.

Knowing the difference between the two might help you make the right choice when looking to procure capsules for your project/s.

So first of, understand that both the hard and softgel capsules are made of gelatin.

Thus the difference between these two types of capsules lies in the design and manufacturing technology.

Here is what I mean:

Hard Gelatin Capsule	Soft gelatin capsule
Made of hard gelatin	Made of soft gelatin
Produced in two halves consisting of a body and cap	Produced as a single piece of gelatin, rather than two halves attached
Mainly used for filling dry and powdered content	Mainly used for oil-based solutions
They’re manufactured using different machines, for shell production and encapsulation. A different process is employed in manufacturing	Manufacturing and filling is done using the same machine, as part of a single process
Hard gel capsules usually are cylindrical	Can be made in a variety of shapes such as the oval, round, tube-like, fish-like, etc.
These are made of only hard gelatin, colorings, plasticizer and titanium dioxide	Lots of ingredients are used, i.e. soft gelatin, plasticizer, sugars, preservatives, colorings, opacifier, etc.
The ratio of gelatin and plasticizer is 1:0.4	The ratio of gelatin to plasticizer is 1:0.8
Available in a range of sizes	Size variety is limited

These are the major differences between Hard Gelatin Capsules and soft gelatin capsules.

And now that we’ve mentioned sizes, do you know the Hard Gelatin Capsule sizes in the market?

Let’s us find out below.

Hard Gelatin Capsule Sizes in the Market

Two-piece Hard Gelatin Capsules vary in size depending on the requirement.

The capsules range from 0.13 mils to 28 mils capacity.

See the table below for more information on specific Hard Gelatin Capsule sizes you can find in the market.

                                                   (HARD GELATIN CAPSULE SIZE   FIG.3)

You can use this table to choose the appropriate size of a Hardgel capsule for your need.

Ingredients Used in Hard Gelatin Capsules Shell

One question that always comes to mind when thinking of capsules is what material is used to make the shells.

Well, the first answer is gelatin.

And in this case, it is hard gelatin.

Gelatin, note, is a compound that’s originally derived from the collagen of animal bones.

This compound is highly preferred for capsule production due to its properties and benefits.

Gelatin forms strong and transparent gels that are easily digestible, and are soluble in hot water.

But gelatin is not all that is used to produce the two-piece gelatin capsules.

Other ingredients are also used to give the capsules a positive binding action, desired shade, and color, etc.

These ingredients include;

• Dye
• Plasticizers to give the gelatin the desired flexibility and elasticity
• sugar
• Edible colorings to achieve the right choice of color ( optional)
• Demineralized water for initial gelatin preparation
• Opacifier (titanium dioxide)
• Glycerin to decrease the capsule’s hardness
• Preservative

Unlike soft gels, hard gels don’t require a lot of ingredients.

The above is enough to produce a desirable Hardgel capsule.

Of course, you need to have the right know-how and machinery to do this.

We’ll discuss the Hard Gelatin Capsule manufacturing process and machinery needed later.

For now, allow me to highlight some of the advantages of Hard Gelatin Capsules.

Why Use Hard Gelatin Capsules

First off, Hard Gelatin Capsules are used in several pharmaceutical, food, and cosmetic industries.

This is because, among other things, hard gels are proven to help strengthen bones, improve health, and grow hair.

Here are more details on why you should use Hard Gelatin Capsules.

· Less expensive

In the capsule filling industry, Hard Gelatin Capsules are known to be the least costly.

These capsules are generally less costly to produce as they don’t need complicated machinery, ingredients or processes.

Compared to soft gels, hard gels are cost-effective to produce, which makes its price in the market affordable.

· Easy to fill

Another primary reason why you should use Hard Gelatin Capsules is that they’re effortless to fill.

These capsules allow you to even fill the capsules as per your dosage need, on your own.

And the best part is that the entire filling process requires less time and workforce to complete.

No matter the type of filling machinery you’re using.

· Ability to meet different demands

The goodness of the Hard Gelatin Capsules is that you can make or get them in a variety of specifications.

Remember that every customer and every industry has different demands.

Therefore, these Hard Gelatin Capsules are readily available in different sizes, colors, prints, and dimensions.

Hard gels, basically can satisfy your need and that of your customers adequately.

· Longer shelf life

Compared to other types of capsules, hard gels tend to have a longer shelf life with minimum maintenance process.

You can store your hard gels in a humidity-controlled area for a long time without affecting its performance.

· Easily digestible

Hard Gelatin Capsules have increased bio-availability of slow soluble nutrients.

As such, they are very easy to digest and can dissolve in the stomach within a few seconds.

These capsules, note, are made of pure gelatin, which increases its effectiveness.

Moreover, the capsules have no taste making them an excellent option to mask the taste and smell of bitter medicine and herbal dosages.

Disadvantages of Hard Gelatin Capsules

Despite many advantages, Hard Gelatin Capsules also have some important drawbacks.

These include;

• A high water content that makes it unsuitable for use with liquid formulations
• Available in only one shape, cylindrical. This makes them unsuitable for a market with varying demands.
• Not suitable for use with highly soluble substances like potassium chloride and ammonium chloride
• Not ideal for use with hygroscopic materials as these may dry out the capsule shell, causing it to become brittle
• Note that a typical Hardgel capsule has between 12% to 15% water content. If this drops much lower, the capsule can crack during handling.
• Only disintegrates in the presence of digestive fluids
• Hard Gelatin Capsule filling machines take a long time to set up, break down, and do cleaning validation due to all the mechanical parts.
• The rapid release of hard gels may cause gastric irritation to end-users due to high drug concentration in localized areas.

Hard Gelatin Capsules Disintegration Time

Hard Gelatin Capsules, once ingested, disintegrate within the first few minutes and quickly release the medicine inside.

Generally, the disintegration time ranges from 3-13 minutes, depending on the size of the capsules.

Note also that there is always a variance in the ratio of gelatin to plasticizer in a hard-gel capsule.

Meaning, how fast or slow a hard-gel capsule disintegrates in the body greatly depends on the amount of plasticizer used.

For drugs that need to be released at specific times and points in the body, target release pellets are often used.

The pellets help to speed up the disintegration time of the capsule, so that contents are released at an earlier time.

Based on all these factors and elements, it is safe to say Hardgel gels capsules take an average of 30 minutes to disintegrate in the body entirely.

Two-Piece Hard Gelatin Capsule Shell Manufacturing Process

Hard Gelatin Capsule shell manufacturing is not a simple process.

It is based on various steps and concerns that we’re going to discuss in this section.

Here is the process:

Step 1: Gelatin Preparation

The first step in this process is to prepare the gelatin.

Here, you need to mix gelatin with hot demineralized water under a vacuum.

Once mixed, let the mixture sit for a while to allow the elimination of air bubbles.

Then, transfer the mixture to a stainless steel service tank and add dyes and water.

Note that at this stage, water (hot) should only be used to adjust the viscosity of the mixture.

Otherwise, it is not necessary.

Step 2: Dipping

Once you achieve the targeted level of viscosity, proceed to dip.

In this case, you’ll need to transfer the processed gelatin solution to the capsule manufacturing machine.

You can do this via a pumping mechanism or using gravity.

Either way, you need to get the mixture to the machine.

Once here, lower the machine plate to the gelatin bath.

Ensure that the pins on the plate are deeply submerged into the solution.

Allow a few seconds for the mixture to coat on the pins.

Note that the thickness of the coating on the pins is achieved by controlling the time of coating.

So beware of how long you let the pins sit in the gelatin solution.

Once coated, let the plate rise to the upper deck, which should release the capsule and its body to get set on the pins.

Step 3: Drying

Coated pins pass through the upper and lower industrial furnace or oven for setting and drying.

Here, gently moving air which is accurately controlled for temperature and humidity remove the moisture from the capsule halves.

Controlling temperature and humidity during the drying process is very critical.

So make sure that you use a machine that can do this precisely.

Step 4: Stripping and trimming

Once the drying process comes to its end, the pin plate enters the table section of the machine.

Here, the capsules are divided into two equal or roughly equal sizes which are then stripped off the pins.

After stripping from the pins, the machine then trims the shells into the required length.

Once the trimming comes to its end as per the requirements, the machine automatically joins the two halves into blocks.

The joined blocks are then shoved into the conveyor belt, which in turn transfers them out to a container.

Step 5: Printing

After completing the manufacturing steps, it is now time for printing.

In this step, you need to print the capsules as per the requirement.

Note that printing can be done in a different form that helps in capsule identification, dosage information, as well as promotion.

This step also notes, is not mandatory. It can only be performed when needed, or rather at the request of clients.

Step 6: Testing

Once the manufacturing and printing of capsules come to its end, capsules transfer to the testing cell.

This is the point where you ensure the quality of the capsules you’ve manufactured.

And for that, the capsules undergo various tests and quality checks which ensure that they’re of good quality.

Also, they have a longer shelf life.

Step 7: Packaging

After completing the test, capsules move to the packaging stage, where they get packed conventionally.

This conventional packing makes handling the capsules easier.

It also ensures longer life of the capsule shell and ease of delivery as well.

This is the entire process of capsule shell manufacturing.

It excludes the filling process, which we’re going to discuss shortly.

Before that, I need you to understand that the complete manufacturing process of Hard Gelatin Capsules is quite tricky.

The process requires a lot of attention and awareness, which you can only assure by using the right equipment.

And, following the right steps.

This is the only way to control quality, thickness, moisture content, size, color, and other specifications to meet yours or your client’s demands.

Hard Gelatin Capsules Filling Process

Capsule filling, also known as encapsulation, is a process of enclosing certain medicines inside empty capsules, allowing them to be taken orally.

And for this to happen, the right formulation has to be made.

To proceed, you need the below machinery and equipment.

· List of Capsule Filling Machine and Equipment

The process of encapsulation requires you to use an encapsulation machine, also known as a capsule filling machine.

This can be a tamping pin or Dosator type capsule filling machine, either of which can be automatic, semi-automatic, or manual.

                        (SaintyCo’sDosator type capsule filling machines  FIG.4)

Apart from the capsule filling machine, you also need support equipment for post-production processes.

Support equipment, in this case, can include;

• Sorting machines used to sort out defective capsules
• Polisher for cleaning and polishing capsules after manufacturing
• Inspection machine; used for the inspection of Hard Gelatin Capsules
• Mixing tank for mixing gelatin with excipients
• Meting system for melting gelatin during gelatin preparation
• Vacuum machine, used for homogenizing and mixing Hard Gelatin Capsule materials
• Capsule printing machine for giving your capsules a unique identity. It prints logos, identification number, capacity, etc.

Now let us take a look at the process of filling Hard Gelatin Capsules.

· Steps in Capsule Filling Process

     ( Simple description of the Hard Gelatin Capsule filling process FIG.5)

The encapsulation process of Hard Gelatin Capsules involves the following steps;

Step 1: Development of Formulation

As we’ve mentioned severally, hard gels are generally filled with dry formulations.

These could be powders, pellets, granules, or tablets.

                                   (Hard Gelatin Capsules content FIG.6)

Certain Hard Gelatin Capsules are also filled with semi-solid or liquid suspensions.

Now, a Hard Gelatin Capsule formulation contains two sets of ingredients, active and inactive ingredients.

The active ingredients are generally the drug compositions while inactive ingredients are simply excipients.

To make the formulation, mix the active and inactive ingredients.

Then, blend the mixture thoroughly to ensure a uniform powder mix.

Step 2: Selection of Capsule Size

Once the formulation is ready, you need to choose the right capsule size to fill.

And here, your choice will depend on your unit dose requirements as well as the formulation you’re using.

So with your formulation ready and dosing weight established, it is easy to define the most appropriate capsule size.

Remember that the body of each capsule has a defined volume.

And, by knowing the density of your formulation, you can easily establish the dosage of each capsule.

                                (Different sizes of Hard Gelatin Capsules FIG. 7)

To make all this easier, use the table given above to choose the right capsule size for your project.

Step 3: Filling the Capsule Body

The filing process varies depending on the type of capsule filler used.

Generally, though, the process begins with placing EGH capsules on a loader tray, placed on top of the filler unit.

The loader then inserts the capsules into the filler unit and is removed.

At this point, the top plate of the filler is lifted to separate the cap from the body of the capsules.

When this happens, you need to fill the unit with fill material, from where capsules will be filled.

After this, the top plate of the machine will drop back into position, where the caps will be placed back onto the filled bodies.

Step 4: Sealing the Capsule

To make the filled capsules tamper-evident, you need to seal the joint between the two halves of the capsules.

For this, you can employ the heat welding process by fusing the cap and body through double wall thickness at their juncture.

This process results in a ring formed around the capsule joint.

Alternatively, you can use a liquid wetting agent to seal your capsules.

Here, a wetting agent is used to lower the melting points of the body and caps which are then thermally bonded.

Step 5: Cleaning and Polishing of Filled Capsules

It is common for small amounts of particles to adhere to the capsule surface after filling.

The particles may be bitter or otherwise unpalatable.

As such, you should clean capsules after filling to remove any powders from the exteriors.

After that, polishing is necessary to restore the shine and aesthetic appeal of the capsules.

If filling a small batch of capsules, cleaning can be done manually by rubbing a clean cloth or gauze over the capsules.

For large scale production, the capsule filler machine can be affixed with a cleaning vacuum.

The vacuum removes any extraneous materials from the capsules as they leave the encapsulator.

Capsules are now ready for packaging!

Hard Gelatin Capsules Quality Control Process

                                                    (Quality control FIG.7)

The biggest concern in the production of Hard Gelatin Capsule filling machine usually lies in how to control quality.

And the best way to ensure quality capsules production, quality must be controlled right from the beginning of the process.

That is, from the raw material selection stage.

Apart from this, there are many other elements like the quality of coloring and technology used in manufacturing.

The quality of packaging, filling capacity, and weighing difference are also factors that can help you to understand quality.

This understanding is critical because the capsule you’re looking to produce is meant for human consumption.

And, if the quality is inferior, there’s no way the capsule can be able to deliver medicine into the body effectively.

So to ensure the quality of your capsules, you should always follow the right manufacturing practices.

Or if you’re buying from a Hard Gelatin Capsule supplier, make sure that the supplier is reputable.

And that he follows the set industry standards on capsule production and formulation.

You need to be sure that the final capsules you have, whether self-manufactured or bought, pass the requisite quality control tests.

This way, you can be sure that the quality of the capsules was never compromised at any stage during manufacturing.

After production, it is also essential to adopt proper maintenance practice to lengthen the life of the capsules.

The storage condition of Hard Gelatin Capsules can greatly affect its quality, so, you should maintain them properly.

Remember that hard gels when exposed to excess moisture becomes soft, losing importance for their intended application.

Types of Hard Gelatin Capsules

Prominently, there are four types of Hard Gelatin Capsules.

These are based on the color and opaqueness of the capsule shell.

And they are;

· Clear Hard Gelatin Capsules

                                           Clear hard gelatin capsules

Clear hard gels are transparent capsules.

These have no color, and you can see right through them, even the content filled in them.

Clear Hard Gelatin Capsules are the ideal choice when you want to show off the color and texture of the contents in the capsules.

The contents you use in this case but be non-light sensitive to avoid degradation.

· Opaque Hard Gelatin Capsules

                                    (Opaque hard gelatin capsules FIG.8)

Opaque capsules comprise of opacifying agents that make them non-transparent.

These capsules are best suited when you want to fill light-sensitive products.

The opaque nature of the capsules will help protect the contents from the effects of light, i.e. degradation.

· Colored Transparent Hard Gelatin Capsules

These are clear capsules with a bit of color.

They are made to allow for a direct view of contents yet include colorings to improve their aesthetic appeal.

You will always find these capsules in a variety of shades such as yellow, green, red, orange, etc.

· Colored Opaque Hard Gelatin Capsules

                                               (Colored opaque capsules FIG.9)

Colored opaque hard gelatin is a perfect choice when you want to distinguish your brand from others.

It is easier for customers to recognize your brand by the color of your products.

For instance, you can choose to have white/green or white/red capsules for your brand.

Color is the most fundamental part of a drugs personality.

It can create emotional appeal, communicate functional values, and benefits.

Color, as I’ve also said, is a great way to distinguish one brand from another.

In other words, you should always choose your capsule color accordingly.

Common Defects in Hard Gelatin Capsules

                     ( Common defects in Hard Gelatin Capsules FIG.10)

As noted earlier in this guide, the process of capsules manufacturing involves a lot of processes.

From mixing, dipping, trimming, packaging, etc.

In the entire operation, you’re expected to produce capsules with zero defects.

Hard gels should be perfect concerning shape, size, appearance, color, texture, taste, and order.

Unfortunately, the many processes involved in manufacturing tend to expose hard gels to several defects that include;

• Shell surfaces not smooth
• Opacify not proper
• Empty capsules after the filling stage
• The foreign matter inside the capsules
• Capsules fitting not uniform during filling
• Capsules are not of the specified type
• Color variation and non-uniformity of appearance
• Surface spots and embedded particles on the capsules
• Capsule may have cracks, breaks, pinholes or splits, losing its integrity

Note that these defects can sometimes cause severe problems.

For instance, a cracked capsule will have contents spilling out and causing unsafe effects to the end-user.

Due to this, it is essential to properly check for defects before dispatching capsules, whether empty or filled.

As a manufacturer/supplier, your responsibility is to protect the end user from any hazardous impacts.

And to achieve this, you need to regulate your inspection system.

You can employ automated sorting machines for this, or go the manual way by conducting visual and physical checks.

Whatever means you use, ensure that you detect and remove any defective capsules before packaging.

Where to Buy Empty Hard Gelatin Capsules

Well, there are so many places where you can buy empty hard gelatin (EHG) capsules.

The only challenge is in ascertaining the reliability of the EHG capsule supplier as this is not easy.

So to save you from all the headaches, I’d like to recommend SaintyCo as the ultimate empty gelatin capsule manufacturer/supplier.

SaintyCo offers short delivery times on a variety of EHG capsules.

Buy from us will help ensure you’re competitive as we supply high-quality capsules that have a longer shelf life.

Whether you need colored, non-colored, opaque, or transparent capsules, SaintyCo is here to deliver.

To help you meet the different demands of your market, we provide a range of capsule sizes for your choice.

SaintyCo’s empty Hard Gelatin Capsule sizes range from #0 to 00.

Our MOQ is also quite considerate compared to other EHG capsule manufacturers in china.

More importantly, we are a certified company whose manufacturing process adheres to the requisite industry standards.

So if you need quality and effective empty Hard Gelatin Capsules at a reasonable price, don’t hesitate to contact us.

We are reachable 24/7 and are ready to offer you a free quote.

Conclusion

From the above, the significance of Hard Gelatin Capsules in the pharmaceutical industry is quite clear.

If you’re into capsule filling and are looking for a versatile capsule to use, Hard Gelatin Capsules are a perfect choice.

NALINIKANTA SWAIN

FORMULATION RESEARCH SCIENTIST

www.nalinikantarnd.blogspot.com