Capsules are enclosed shells mainly made up of gelling agents that can provide suitable human conditions inside a human stomach. They enclose a pharma product without any additional mechanism, material or manufacturing process.

The types of medication that can be contained inside the capsule shell can be many, such as powder, granules, liquid or a combination of these. The selection of material inside it depends on the drug requirement, disease to be cured and target patient population.

Capsules are common in oral pharmaceutical dosage forms, among others. Various variants of solid oral dosage used in the pharmaceutical industry can take different forms. Some oral forms can only be administered in capsules, while others can only be administered in tablets. Some oral forms can be administered in both tablets and capsules.

Advantages of capsule in pharmaceutical industry

Before we discuss the selection criteria for capsule in pharmaceutical industry, let's briefly discuss some advantages of capsules

Easy to encapsulate drugs

Capsules provide an easy and convenient way to encapsulate a drug inside it. The main reason is that various capsule processing equipment, such as filling machines, can be selected for a specific product.

Additionally, the chemical composition of drugs and material categorization of capsule shell makes it easy for pharma manufacturers to encapsulate the pharma product with desired characteristics such as rate, time and location of drug release inside a patient’s body. These material and chemical characteristics can easily be altered if proper equipment is unavailable, given the regulatory and quality guidelines allow them to do so.

Fast acting

Capsules, compared to other forms of oral dosage, act fast to cure the disease and relieve the patient. There is a significant lead time for tablets related to tablet disintegration inside the stomach and the final impact on curing the disease.

On the other hand, capsules are easily integrated and become part of human metabolism inside the human stomach. Their shells comprise natural agents that facilitate easy integration of the material encapsulated. This decreases the lead time in dissolving the drug inside the stomach, subsequently curing the disease and giving relief to patients.

Easy product development

Product development is easy for the capsule form of oral dosage and does not require complex tasks compared to tablets, such as tablet integration, stability and quality checks. The encapsulated material only needs development at the initial stages, often performed in the granulation stage.

Capsule shells are pre–qualified by the supplier as a part of their responsibility. So it decreases the final steps, time and cost of capsule product development. This advantage increases the share of pharma manufacturers in revenue, profit, high quality and timely delivery of the products compared to its competitors.

Multiple fill options

Capsules provide options for filling different dosage forms in a single capsule without worrying about product compromise and quality issues. Each strength of a product can be consumed differently from the other without disturbing the quality or efficacy of one product.

For tablets, it is not easy and only becomes possible after detailed activity to study the impact of one product on other. Only when it is scientifically proved that different dosage strengths and forms cannot affect each other and are safe for human consumption can they be combined in a single tablet form.

Require fewer steps then tablets

Capsule manufacturing requires fewer steps as compared to tablets. The material to be encapsulated is manufactured in the granulation stage, a common manufacturing process related to capsules and tablets.

Capsules only require one additional piece of equipment known as a filling machine, which is easily available, thanks to development in pharma equipment technology.

To qualification of the capsule shell is the responsibility and is performed by the suppliers. Although the capsule user is also responsible for ensuring quality, it mainly depends upon the supplier or manufacturer.

The capsule supplier or manufacturer is responsible for providing adequate documents to show proof that the quality of capsules is according to regulatory guidelines, contains adequate material characteristics, does not affect the patient's health and the material of manufacturing is approved before its manufacturing.

Quality testing is also significantly reduced in the capsule case because of the supplier's involvement.

This contrasts with a tablet requiring a series of steps to manufacture. It also requires a significant amount of intermediate equipment before the material takes the form of a tablet.

At the tabletting stage, tablet formation also requires equipment and processes. Quality testing and qualification are also significant in tablet form and must be performed and required at each stage from beginning to finish.

Types of criteria for pharmaceutical capsules

Before we discuss, selection of capsules, let’s look at some common selection criteria for capsules in pharma industry

Capsule material

The most common selection criteria type is the material type to be encapsulated inside it. Commonly, there are complex and liquid gelatin capsules.

Hard gelatin capsules are composed of upper and lower parts. They are used to enclose dry material and are called Dry filled capsules.

During filling, the upper and lower parts of the capsules are separated. The material to be encapsulated is filled in the lower part. After filling, the machine automatically tightens and seals the upper part with the lower, forming a resultant final finish capsule.

Soft gelatin capsules contain added moisture in shell composition. Soft gelatin capsules seal liquid, suspension or a combination of both. Unlike hard gelatin, soft gelatin capsules are manufactured in a single go, without opening any part of it. These capsules also contain plasticizers, which are added to increase the plasticity and plasticity of capsules.

Capsule Size

Cancun size is its physical dimension and represents the drug quantity in a capsule shell. The capsule size is represented numerically - size 000 is the largest, while size 5 is the smallest.

Large-size capsules can contain large quantities of the drug inside their shell, increasing their weight. The capsule size is also considered and adjusted according to the patient's ability to swallow the capsule. Because some patients might face difficulty swallowing a particular-sized capsule, which can affect the patient's treatment plan, difficulty in swallowing also forces the patient to skip a dose, or some might discontinue the medication.

Capsule size also affects the transient time of the drug, i.e. a shift from the mouth to the stomach where it is intended to be released, and becomes part of human metabolism. If a properly sized capsule shell is not selected, the capsule will not disintegrate at its correct place, i.e. in the stomach. It can lead to additional complications such as ulcers and perforation.

Selecting capsule for a pharma product

Let's discuss some critical parameter to consider when selecting a capsule for your oral solid dosage form

Regulatory guidelines

The pharmaceutical industry is highly regulated, and pharma manufacturer is legally and morally bound to their regulations. Like other areas of industry, such as equipment, quality and production, the regulatory body also provide guidelines to select the proper capsule type that best optimizes the capsule’s therapeutic effects.

Additionally, once published, regulatory bodies update their regulation from time to type in response to various factors such as feedback, market complaints, technological advancement and innovation.

Following regulatory guidelines has many advantages, including the following.

• Access to regulated markets worldwide for all products without any further inspection and compliance requirements. It helps to increase the Pharma manufacturer’s market footprint, share and revenue and increases customer trust.

• Regulatory bodies often provide updated guidelines on using various capsules for treatment plans.

• Regulatory guidance also helps prevent any adverse effects of a capsule under specific conditions, such as patient complexities.

Processing equipment

Another primary consideration when selecting a capsule is whether or not the required equipment is available.

For capsule products, the standard equipment in manufacturing is the capsule filling machine.

The capsule equipment should be able to provide the highest standards of Pharma products with minimum possible rejection and damage to capsule shells. Capsule damage is typical when the upper and lower jaws are not aligned.

Equipment is also selected, whether you require to fill powder, tablets, palette, liquids or a combination of these materials.

The equipment also specifies the type of shell that it can process. Some equipment can only be used to process hard gelatin, while others can only be used to process soft gelatin

What is your target patient?

Capsule type also depends upon the target patient population for which you manufacture the product. Capsule physical parameters affect the behaviour of the patient in taking these medications. Although the solid oral form is the most convenient to administer and easy to understand, it still can be difficult for some patients to administer.

Some capsule types can also become difficult for specific age group patients because they may face difficulty swallowing them – a reason related to capsule physical size and shape. This can increase complications related to Pharma products, such as undesirable transient time and integration before its intended location. This condition can result in severe complexities, such as an ulcer in patients.

Another factor to consider related to patients is their age. Children and adult patients are more likely to face difficulty swallowing capsules than adults.

Certain medical conditions of target patients, such as Parkinson's or muscular dysfunction, can also affect the capsule selection criteria for a pharma product.

About the Author

Muhammad Asim Niazi has a vast experience of about 11 years in a Pharmaceutical company. During his tenure he worked in their different departments and had been part of many initiatives within the company. He now uses his experience and skill to write interested content for audiences at PharmaSources.com.