HPMC Capsule: The Ultimate Guide

Drug administration has become very simple today.

You can actually take very bitter medication under the disguise of sweet, good scented HPMC capsules.

In this guide, we are going to take you through a type of capsule known as HPMC capsule.

You will know the uses, merits, and safety concerns among other significant information of HPMC capsules.

What are HPMC Capsules?

HPMC capsules are types of drugs with Hydroxypropyl Methylcellulose as the main ingredient for the capsule body and cap.

HPMC Capsules

It is a safe drug for human consumption and a good alternative for gelatin capsules because of the vegetable source.

What is Hydroxypropyl Methylcellulose?

Hydroxypropyl Methylcellulose is an ingredient which you can also identify as hypromellose.

It is a soluble methylcellulose ether that you can easily extract by chemically manufacturing polymer cellulose.

Cellulose is the most significant constituent and polysaccharide of all the plant structures.

Hydroxypropyl Methylcellulose: Image source: Science Direct

Hydroxypropyl Methylcellulose has a better appearance and comes from a vegetable source thus making it a perfect alternative for gelatin.

You can use it as a binder, thickening agent, hydrophilic matrix material, and a film former.

Apart from that, you can also use Hydroxypropyl methylcellulose for controlling the release of hydrophobic and hydrophilic drugs.

Such properties make it a very good ingredient for making capsules.

Reasons for Using HPMC Capsules

You can opt to use HPMC capsules because of the following advantages:

Hard gelatin capsules structure

• HPMC capsules are easy to swallow as it masks the horrible taste and smell of the inner active ingredients.
• It is an organic, and natural alternative for delivering drugs into the body.
• Offers a good alternative for the people who do not consume animal products such as vegetarians.
• A perfect alternative for the people who follow a strict religious diet because it is kosher and halal.
• It has a considerable moisture content that maintains the integrity of the internal active capsule ingredients.
• You can store it for a very long time without the fear of bacterial growth on the HPMC capsules.
• The capsules are also available in different sizes, shapes, patterns, and colors that match diverse medical needs.
• Allows for the inclusion of certain ingredients that will contribute to delayed disintegration.

You can, therefore, use it as a targeted drug that will only disintegrate when it reaches the right target.

• Does not exhibit cross-linking problems since it has a polymer that is free of amino acids.
• Has a flexible film of different dimensions that allows quick dissolution in different solutions at varying temperatures.
• It is free of preservatives, starch, allergens, and gluten thus making it a healthy alternative for drug administration.

Disadvantages of HPMC Veg Capsules

Some of the reasons why you may choose to ignore HPMC capsules include:

• Cost of manufacturing HPMC capsules is higher in comparison to that of other capsules such as gelatin capsules.
• The main ingredients for making HPMC capsules are usually not easy to find thus complicating the manufacturing process.
• HPMC capsule walls are much weaker in comparison to the gelatin cells prompting you to handle with more care.
• It may cause side effects to some users over a long period if one does not obey the daily dosage.

HPMC Capsules Side Effects

Remember, HPMC is an E464-listed food ingredient.
Therefore, you should find out how frequently or how many times you will consume the HPMC capsules.
Remember, E464-listed food ingredients may cause bloating, diarrhea or constipation. But this only happens if you consume large quantities of Hydroxypropyl Methylcellulose.
At the moment, JECFA, EU, and FDA, have approved the use of HPMC due to significantly low adverse effect level.

HPMC Capsule Disintegration Time

The dissolution behavior and time of HPMC capsules will depend on:

Capsules disintegrating – Photo source: Torpac

i. The type of disintegration media.

ii. Disintegration media temperature

iii. Size of the HPMC capsule

HPMC capsules exhibit a delay in dissolution in different dissolution media and temperature.

It took longer to disintegrate and dissolve in low pH solutions than in higher pH solutions.

HPMC capsule will take as long as 4 minutes to disintegrate in most of the solutions.

HPMC Capsules Uses in the Pharmaceutical Industry

In the pharmaceutical industry, you can use HPMC capsules for the following purposes:

• HPMC capsules aid in delivering medication that has nasty and unpleasant tastes and smell.

This is because it has better odor and scent that masks the unpleasant smell and taste.

• You can also use the HPMC as a visualizing agent, bioadhesive, coating polymer, binder, and solid dispersion for better solubility.
• Due to the delay properties of HPMC, it is a proper capsule for the administration of target drugs.

HPMC capsules will only disintegrate once it reaches the target.

• It is the main method of administering supplements to the body especially for the ingredients that react with gelatin.
• As an alternative to gelatin, it offers the pharmaceutical industry an opportunity to serve the vegans.

Vegans and people following a strict religious diet can now get their drugs in capsule form thanks to HPMC capsules.

Safety of HPMC Capsules

As soon as you see the inclusion of the word vegan or vegetarian, you probably think of organic or healthy.

So is the case with HPMC capsules which come from cellulose fibers and, therefore, a natural type of capsule.

The use of cellulose fibers makes HPMC capsules a safe mode of drug administration.

The use of HPMC capsules, therefore, has good news for vegetarians and people who avoid animal products completely.

Despite the high proclamation of safety, there are certain factors that you should consider to declare it completely safe.

You have to adhere to the daily recommended dose of capsules.

Apart from that, the rigorous manufacturing process involves the use of highly reactive, toxic or harmful substances.

At the end of the manufacturing process, manufacturers remove these substances.

Despite the removal of these substances, it is imperative to question whether HPMC capsules are still safe.

HPMC Capsules Formulation (Know What HPMC Capsules are Made Of)

HPMC capsules are made of the following ingredients:

Two-piece capsule – Photo source: Capsugel

· Hypromellose

This ingredient is a product of natural fiber and polymer you can identify as cellulose.

It is a natural product that is responsible for the vegan properties of the HPMC capsules.

· Water

This is the main liquid ingredient that you can use for mixing all the HPMC ingredients.

You will add water considerably according to viscosity or thickness of the HPMC capsule you require.

· Food additives such as Pullulan and Gellan Gum

Food additives assist in the delivery of active ingredients in the HPMC capsule.

The most common food additives include:

i. Pullulan which is a water extract from fungi growing on a substrate of starch or other significant sources.

ii. Gellan gum is also a water-soluble anionic polysaccharide from sphingomonaselodeafor bacterium.

It works as a gelling agent for capsules and increases the delaying properties of the HPMC capsules.

· Artificial Colorants

You can use different types of artificial colorants to provide the HPMC capsules with the color shade you desire.

· Sweeteners such as Sorbitol

The sweeteners help in masking the horrible taste of the active inner fill medicinal ingredients.

· Carrageenan

It is the substance that you will use in thickening or increasing viscosity of the HPMC capsules.

It is a product of purple and red seaweeds that consists of different mixtures of polysaccharides.

· Sodium Laurel Sulfate (SLS)

You will include Sodium lauryl sulfate as an effective emulsifying and foaming agent of HPMC capsules.

How Hydroxypropyl Methylcellulose (HPMC) Capsule Work

Just like any other form of a capsule, HPMC capsules work by disintegrating the active medicinal product at the target spot.

Capsule in the stomach – Photo source: skyepharma

Once you take the HPMC capsule, it goes all the way to the stomach.

You do not have to worry about the drug sticking on the esophagus as it travels to the stomach.

This is because it is moist enough to allow the capsule to glide well all the way to the stomach.

Once in the stomach, the capsule will mix with the dissolution media in the stomach.

It will take approximately 4 minutes before it disintegrates inside the stomach.

Apart from that, some HPMC capsules also have enteric properties making them resistant to acidic conditions.

Since the stomach has acidic conditions, HPMC capsules will not disintegrate in the stomach.

It will pass all the way to the duodenum or upper intestines where the pH is higher and disintegrate.

It releases the medicinal properties which will dissolve and take care of the problem.

HPMC Capsules Manufacturing Process

Two-piece capsules manufacturing process – Photo courtesy: Clinical Gate

Step One: Preparation of the Ingredients

First, you will have to collect all the HPMC capsule ingredients such as hypromellose, water, and artificial colorants among others.

Measure the right quantities of the ingredients and then thoroughly mix them to form a uniform mixture.

You will then heat the mixtures in a heated jacketed melting tank for about three hours.

As it heats the ingredients, it mixes them to form a HPMC solution.

Transfer the HPMC to a receiving hopper on the encapsulation machine.

Step Two: Dipping and Spinning Pins into the HPMC Solution

Once in the hopper, ensure that you maintain the temperatures at a certain level to keep it in a liquid state.

The machine will automatically dip the pin moulds into the HPMC solution.

Since the pin mould are of a lower temperature, the HPMC solution will tend to stick on the mould pins.

Remove the pins and make sure that it is spinning as it moves to the next stage.

The spinning ensures that the HPMC solution spreads perfectly to form a uniform body and cap.

Note that the pins for forming the body and those of forming the caps are of different sizes.

Step Three: Drying HPMC on the Pins

The pins will go through a drying kiln to dry the capsules.

A series of air blowing over the pins to dry them to a considerable moisture content.

You should be careful not to melt or over dry the capsules.

Step Four: Stripping HPMC shell from Pins

After that, you have to ensure that you remove the HPMC from the mould pins.

Since the thickness of HPMC is smaller, you will employ the use of special equipment.

This equipment will remove the HPMC from the pins, and then cut them into considerable sizes.

Step Five: Joining the Body and Cap

The same happens to the other pins that form the cap of the capsule.

Since they are of different sizes, the body and the cap will fit in perfectly as you attempt to join them.

Remember that this is a temporary seal as the empty capsules await the filling process.

Step Six: Printing or Labeling of the HPMC Capsules

After that, the HPMC capsules will go through a printing and labeling machine on a conveyor belt.

The machine will print unique codes and dates that will help in the identification of the HPMC capsules.

Step Seven: Quality Control of HPMC Capsule

It will then move to the quality control center where a sorting machine awaits.

The sorting machine will get rid of all the capsules with defects and allow the perfect ones to proceed.

It will sort them in terms of shape, size, and detect if the capsules have dents or imperfect formations.

Step Eight:  Filling and Sealing HPMC Capsules

Once the capsules are complete, you can now fill them with the right filling materials.

Prepare the filling materials and add them to the filling machine hopper.

The filling process will vary according to the type of machine you choose to use.

Among the various capsule filling machines you can use include:

i. Use of dosator capsule filling machine

ii. Use of tamping capsule filling machine

iii. Manual capsule filling machine

Remove the cap of the capsule and strategically place the HPMC capsule body under the filling jets.

The machine will accurately fill the capsules with the right quantity of inner fill materials.

After that, the machine will automatically place the caps and seal them completely.

The next step is packaging and storage as the HPMC capsules await transportation.

HPMC Capsules Specifications

When choosing an HPMC capsule, you should focus on the following:

i. Hypromellose Capsule Size Chart

As you consider the size of the capsules, you have to look at the following details:

i. Overall closed length when the capsule is fully locked.

ii. Individual lengths of the body and the cap in either inches or millimeters.

iii. External diameter which includes the diameter of the cap and the body.

In that case, the most common capsule sizes you will definitely come across range from 000 to 5.

000 is the biggest capsule size while 5 is the smallest HPMC capsule size.

Capsule sizes

The capsule sizes include, 000, 00E, 00, 0E, 0, 1, 2, 3, 4, and 5.

For instance, HPMC capsule size 000 may have:

• Cap length of 0.51 inches and a body length of 0.874 inches
• Body diameter of 0.376 inches and cap diameter of 0.390 inches

ii. Colors of Hypromellose Capsules

The capsule colors differ in terms of the active color ingredient and the colorant group.

The colorant groups can either be the group I, or group II.

Group I exhibits the same color for both cap and body.

Group II exhibits different colors for the cap and the body.

Apart from that, the HPMC capsule can either be transparent, semi-transparent, or opaque.

The most common capsule colors are white, pearl white, black, orange, red, maroon, purple, blue or brown among other combinations.

iii.  Quality Standard for HPMC Capsule

HPMC has to go through quality tests and approval by the following:

• USP – United States Pharmacopeia
• JP – Japan Pharmacopeia
• FDA – Food and Drug Administration
• cGMP – Current Good Manufacturing Practice
• EP – European Pharmacopeia
• BP – British Pharmacopeia
• FCC – Food Chemical Codex
• OR – Organic Reagents
• NF – National Formulary

iv. Volume/Capacity of Hypromellose Capsule

The volume or capacity of HPMC capsules varies according to the size of the capsules.

HPMC empty capsule volume or capacity varies as in the table below.

Capsule Size	Capsule capacity or volume (ml)
000	1.37
00E	1.00
00	0.90
0E	0.78
0	0.68
1	0.48
2	0.36
3	0.27
4	0.20
5	0.13

HPMC Capsules vs Gelatin Capsules (How they Compare)

Gelatin Capsules	HPMC Capsules
Main coating ingredient originates from the hydrolysis of animal products such as skin, tendons, bones, and cartilages.	Main coating ingredient originates from the cellulose of plant materials such as tree trunks or tapioca.
Not good for people who do not consume animal products or follow strict religious diets.	A healthy alternative for vegans and people who avoid the consumption of animal products.
Consists of hard gelatin capsules with enteric properties making the acid-resistant and might delay the disintegration process.	Have the enteric properties similar to hard gelatin capsules thus good for people experiencing stomach irritation after capsule consumption.
Experiences cross-linking	Does not experience cross-linking
Masks the horrible taste and smell of the active medicinal ingredients and is easy to swallow	Easy to swallow as it masks the nasty taste and smell of the active medicinal ingredients.
Has a very long shelf life without any risk of bacterial growth	Just like gelatin capsules, you do not have to worry about bacterial growth on the capsules in storage.
Available in different shapes, colors, sizes, and patterns that will match the different medical requirements.	HPMC capsules are also available in different colors, shapes, patterns, and sizes that will fit your medicinal needs.

How HPMC has Changed the Role of Capsule Form

HPMC two-piece capsules

· HPMC is Becoming a New Standards for Capsule Polymer

HPMC is meeting the new trends in the market where people are turning to the consumption of healthier products.

It has the ability to meet the dietary needs of religious societies and can withstand temperature excursions.

Thermogelation of HPMC capsules also eliminates the prospects of using gelling agents in making capsules.

Such advancements also give HPMC capsules pH-independent disintegration thus becoming a better alternative to gelatin capsules.

Such developments make HPMC a preferable capsule to both consumers and pharmaceutical manufacturing companies.

· Acid Resistant HMPC Capsules

HPMC capsules also have enteric properties making them resistant to acidic conditions thus a healthy alternative for nutritional supplements.

Acid resistant capsule incorporates certain gelling agents that allow it to withstand the acidic stomach conditions and then disintegrate in the duodenum.

This property allows it to become an alternative for the people who experience stomach irritations after consuming the gelatin capsules.

It is a material of choice for probiotics, mineral and herbal formulations in the current pharmaceutical market.

·  Improving Bioavailability

It interacts with API’s that are poorly soluble thus leading to a low rate of crystallization in the GI tract.

This can assist in dosing high energy salt forms or where there is over-saturation of APIs in the intestine.

HPMC capsules assist in the maintenance of supersaturation and inhibit crystallization depending on the application.

The increasing technologies in the development of HPMC capsules meet the demands of the current market requirements thus eliminating gelatin.

Suitable HPMC Capsules Storage Conditions

You should store the HPMC capsules under the following suitable conditions:

• Make sure the packages are not open
• Relative humidity should vary between 40 to 60 percent.
• Temperatures should vary between 20°C to 35°C.
• Store then away from hot water, direct sunlight, air radiators, and steam pipes.
• Raise pallets off the ground and place the capsule packages on them.
• Do not store the empty capsules in freezing conditions such as the freezer.

Current Status and Future Prospects of HPMC Capsules

Currently, you can use HPMC for certain food preparations and pharmaceutical applications.

Apart from that, you can use it as a coating polymer, thickening agent, bioadhesive and solubility enhancer among other things.

It is also the best alternative to the two-piece gelatin capsules.

Despite the current developments, there is a very bright future for the HPMC capsules.

Scientists are looking forward to taking advantage of HPMC to meet the rising demand for healthy capsule alternatives.

This includes coming up with cheaper, better and more efficient manufacturing processes for the HPMC capsules.

Apart from that, they are also researching further to improve in vitro or in vivo dissolution and enhance its superiority.

Conclusion

Well, drug administration is progressing to higher levels as days go by.

HPMC capsules are becoming the most important form of drug administration and it can even be better.

With this information at hand, you can venture into the business of HPMC capsules because it has a brighter future.

You can as well consider consuming them due to their safety and health benefits.