A close-up shot of multicolored bulk capsules.

10 Key Definitions You Should Know About Capsules

Given how frequently capsules are used in bulk manufacturing, it is essential to understand the fundamental words linked to them. Understanding these words improves stakeholder communication, increases comprehension of capsule production and drug behavior, informs regulatory rules, patents, and literature, and helps with problem-solving throughout manufacture. It influences the safe and efficient delivery of medication in addition to fostering informed decision-making and effective patient counseling. Therefore, it is crucial for everyone—from those involved in the design and production of these pharmaceuticals to healthcare professionals and the patients who depend on them for their health—to have a clear understanding of these concepts.

Knowing key definitions in pharmaceutical manufacturing and drug formulation is critical due to several reasons:

  • Drug Formulation: Drug formulation is the process of mixing several chemical ingredients to create a finished therapeutic product. Understanding this process aids in the selection of the optimal ingredients to improve drug distribution and therapeutic impact. It enables the pharmacist to modify the physical and chemical features of the medication ingredient in order to assure its stability, safety, and efficacy.
  • Excipients: Excipients are non-active substances found in pharmaceutical compositions. They can improve taste, manage the release of active ingredients, and improve stability, among other things. Understanding their role is critical for formulation success.
  • Bioavailability: The extent and pace at which an active drug ingredient is absorbed from a drug product and becomes available at the site of action is referred to as bioavailability. It is critical for determining the drug’s efficacy in the body.
  • Stability: Stability refers to a pharmaceutical product’s capacity to retain its chemical integrity and physical properties over time. Understanding stability is critical for assuring the drug’s efficacy and safety throughout its shelf life.
  • Good Manufacturing Practice (GMP): These are the principles that ensure products are produced and controlled in accordance with quality standards on a regular basis. Understanding GMP is essential in the pharmaceutical sector for quality control and regulatory compliance.
  • Dosage Form: This relates to the medication’s physical form, such as tablets, capsules, liquid suspensions, and so on. It influences the route of administration, drug release rate, and patient acceptance, making it a critical factor to consider when developing a medicine.

Whether you are new to capsule filling or a seasoned bulk manufacturer, let’s now delve into 10 key definitions you should know about capsules, an essential form of drug and supplement delivery, to deepen our understanding of their design, composition, and function.

1. Active Pharmaceutical Ingredient (API)

An Active Pharmaceutical Ingredient (API) is a biologically active component of a pharmaceutical medicine that is intended to provide a therapeutic impact or directly engage in illness mitigation, treatment, cure, or prevention. During the pharmaceutical formulation process, capsules are filled with the desired API or a mixture of APIs and other excipients. The nature of the API to be filled, including its physical and chemical qualities, dosage, and planned release characteristics, will frequently influence the choice of capsule material, size, and other factors.

Bulk collagen powder and capsules in spoons

APIs play a significant role in capsule manufacturing, fundamentally shaping the process and final product. As the key substances that exert the therapeutic effect, APIs determine the capsule’s purpose and therapeutic classification. The physical and chemical properties of the API influence the suitable dosage form, whether hard or soft capsules, and dictate the capsule shell’s design. APIs also affect the choice of compatible excipients, which must not react adversely with the API, compromising its stability, efficacy, or safety. They guide the formulation and manufacturing processes to achieve desired release characteristics, ensuring the drug is released at the correct rate and at the proper site within the body. The API’s strength determines the dosage, and it is subject to rigorous quality control and assurance checks to verify its identity, strength, quality, and purity, thus underlining the API’s central role in successful capsule manufacturing.

2. Altered Release

In the context of capsules, Altered Release refers to a sort of pharmaceutical delivery system that controls or prolongs the release of a drug over a specific time period following ingestion. This is in contrast to immediate-release formulations, which are meant to disintegrate and release medication as soon as it is consumed.

There are various sorts of altered release mechanisms, such as:

  • Controlled-release (CR) capsules, also known as sustained-release (SR), slow-release (SR), or extended-release (ER, XR, XL), are designed to gently release their medication over an extended period of time, typically 12 to 24 hours. This can assist in maintaining a consistent, appropriate level of medication in the body and reduce dosage frequency.
  • Delayed-release (DR) capsules are meant to remain intact after passing through the stomach. They release the active component in the intestine to improve absorption or to prevent irritating the stomach lining.
  • Targeted-release capsules are intended to release medication in a specific area of the digestive tract. This could be because the treatment is more effective in a certain spot or to limit negative effects in other areas of the body.

Altered release capsules have a number of advantages, including enhanced patient adherence to pharmaceutical regimens due to lower dose frequency, better symptom control, less side effects, and optimal medicine utilization within the body. 

3. BodyDrawing showing short top part of capsule (Cap) and longer bottom part of capsule (Body)

The bottom half of a capsule is called the Body. During capsule filling, the body is usually the part that contains the active agent or substances, whether they be in the form of a powder, a liquid, or tiny time-release beads or pellets.

The cap is placed on top of the medication or supplement once it has been inserted into the body. The capsule’s shape makes it easy to swallow and protects the contents from injury or degradation. 

4. Cap

The Cap is the top half of the capsule and is placed over the body to contain the substance and complete the capsule. The closed capsule forms a protective shell around the medication, making it simpler to swallow and, in some situations, shielding the stomach from potential irritation from some ingredients.

5. Capsule Filler

Empty capsules are made into medicine or nutritional supplements by a Capsule Filler machine. Capsule fillers range in size from small handheld manual devices to large, industrial machines used in mass production by the pharmaceutical industry.

There are mainly three types of capsule fillers:

  • Manual Capsule Fillers are portable or tabletop devices that are usually used for personal or small-scale production. Typically, they operate with no more than 100 capsules at once. All by hand, the user separates the capsules, inserts the capsule bodies into the device, fills them with the desired substance, and replaces the capsule lids.
  • Semi-Automatic Capsule Fillers are more complex, larger machines and can fill a greater quantity of capsules simultaneously. They operate by a combination of manual loading with automated filling and capping, which can increase precision and productivity.
  • Automatic Capsule Fillers are large machines used in the pharmaceutical and dietary supplement industries. Per minute, they can load hundreds to thousands of capsules. These capsule fillers automate the entire process, including separating the capsules, filling them, and replacing their caps, and frequently include quality control systems as well.

The substances used to fill capsules may be grains, granules, pellets, liquids, or semisolids. The selection of capsule filler frequently depends on the scale of production, the substance being encapsulated, and the product’s specific requirements, such as dosage accuracy and production speed.

6. Diluent

Diluent is an inactive ingredient used in pharmaceuticals and supplement production. It is also known as a filler and increases the bulk of the formulation to a size acceptable for capsules, ensuring that each one has the correct dosage of the API. Diluents also increase powder mix flowability and aid in the disintegration and dissolution of capsule contents after intake. Magnesium stearatemicrocrystalline cellulose, and starch are examples of common diluents.

White excipient powder

7. Disintegrant

After consumption, a Disintegrant aids in the breakdown of a capsule in the body, which in turn allows the API to be dispersed for absorption. They do this by absorbing biological fluids and swelling, thereby dissolving the capsule. Cornstarch and microcrystalline cellulose are examples of common disintegrants. The disintegrant used is determined by the qualities of the medicine, the production procedure, and the route of administration.

8. Gelatin

Gelatin, a protein derived from animal collagen found in bones, skin, and connective tissues, is used traditionally to create the majority of capsules in the market. Gelatin capsules are popular for several reasons:

  • Solubility: Gelatin is soluble in body fluids, which allows for the quick release of the medication or supplement contained within the capsule once ingested.
  • Easy to Manufacture: The gelatin manufacturing process is well established, making it a cost-effective choice for capsule production.
  • Versatility: Gelatin can be used to make both hard and soft capsules, and can be modified to alter the dissolution time to fit specific needs.
  • Tasteless and Odorless: Gelatin is naturally tasteless and odorless, which makes it an excellent choice for encapsulating substances with unpleasant tastes or smells.
  • Safety: Gelatin has a long history of safe use in the pharmaceutical and food industries. It is easily digested and typically does not cause adverse reactions.
  • Appearance: Capsules made from gelatin have a smooth and glossy appearance, which can be more appealing to consumers.

9. Vegetable Capsules

There are other materials besides gelatin that are utilized in the manufacture of capsules, such as the vegetable capsules made from HPMC and pullulan

HPMC (hydroxypropyl methylcellulose) comes from the plant fiber cellulose. HPMC is a vegetarian and vegan alternative to animal-derived gelatin and is perfect for consumers with various diets and allergy restrictions. Resistant to heat and humidity and ideal for challenging storage conditions, HPMC capsules can be filled with a variety of ingredients.

Like HPMC, pullulan capsules provide a vegetarian- and vegan-friendly substitute for gelatin. Pullulan is a naturally occurring, water-soluble polysaccharide created by the fungus Aureobasidium pullulans. This biopolymer is safe and environmentally favorable to use in the creation of capsules since it is fermentable, edible, and non-toxic. Although they are not immune to heat and humidity like HPMC capsules are, pullulan capsules do have excellent oxygen barrier properties, making them the ideal choice for oxygen-sensitive ingredients.

10. Hard Gel

Hard Gel refers to the type of gelatin capsule that is rigid and hard when dry, but softens and dissolves when consumed, as opposed to soft gel, which has a flexible shell with a liquid formulation. Typically, they are filled with dry, powdered ingredients, but could be used with liquids that do not break down gelatin.

Graphic showing one piece soft gel capsule in comparison to a two piece hard gel capsule

Understanding these key definitions will allow you to use capsules in production with confidence. You will be able to design and improve your goods more intelligently using these insights.

Do you have any other questions regarding capsules? Or are you looking for a bulk capsule supplier? The dedicated and knowledgeable sales staff at Vivion is always available to assist you. We want to assist you in reaching your maximum potential, whether you are an experienced manufacturer or just starting out. Please contact us if you require additional assistance or want to learn more about our vast inventory of empty hard capsules and services. Get in touch with the Vivion sales team right now to find out how we can help you bring your product concept to life.

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