Hard Capsules – Use, Types and Production

What are the types of hard capsules, where are they used, and what are their advantages?

Key takeaways

• Hard capsules are the optimal dosage form for medicines and dietary supplements — they ensure effective delivery of active ingredients.
• Their quality determines the bioavailability and efficacy of the ingredients of medicinal products (pharmaceuticals) and food products (dietary supplements).
• The availability of different types of capsules provides great flexibility in the selection of the formulation (dosage form) of the preparation and allows for very accurate dosing of active ingredients.

What are they and what are their uses?

Hard capsules are capsules consisting of two snap-fit parts – the upper part (the so-called cap/lid) and the lower part (body).

Most often, hard capsules are filled with powder or granulate.

The universal properties of empty capsules enable the use of various formulations. The main task of capsules is to protect substances against external factors and their optimal release at the target site of the digestive system.

Application in the pharmaceutical industry

Hard capsules are widely used in the production of medicines. They are particularly suitable for substances sensitive to moisture, light, and oxygen. They protect the contents and ensure their stability.

In pharmacy, hard capsules are used for:

• production of multi-ingredient medicinal products
• controlled-release drugs
• administration of active substances with an unpleasant taste

Advantages of capsules

1. Rapid release of active substances in the digestive system.
2. Optimal protection of contents against the external environment (oxygen, light, moisture).
3. Optimal release depending on the shell structure (immediate or controlled).
4. Formulation flexibility — the ability to fill the capsule with various types of substances.
5. Ease of swallowing thanks to the smooth surface.
6. Masking the taste and smell of medicinal substances.
7. Precise dosing of active substances.

Capsules vs. tablets

To put it simply, a tablet is a substance or mixture of active substances (in the case of dietary supplements, active ingredients) prepared by compression. In a capsule, on the other hand, a substance or mixture of substances is enclosed in a special shell that dissolves in the digestive tract and releases its contents into it.

For many people, capsules will be a better choice because, unlike tablets (especially uncoated tablets), they have an imperceptible taste, which makes them easier to swallow.

Moreover, capsules dissolve faster in the digestive system, which translates into faster release of their contents and faster action.

Types of hard capsules

• gelatin
• hydroxypropyl methylcellulose (HPMC)
• pullulan
• starch
• polyvinyl alcohol (PVA)

Summary

Hard capsules are a proven solution used for years in the production of medicines and dietary supplements. Their quality, rapid release of active substances and universal application are features that are irreplaceable in the market of pharmaceutical and food production.

Taking care of every element of the product contributes to the highest quality of the final preparation.

FAQ

What is the purpose of using capsules?

• Capsules mask the unpleasant taste or smell of the medicine, protect the active substance against external factors, and enable controlled release of the substance in the body.

Are capsules safe?

• Capsules are safe and well-tolerated by the body. Gelatin is a natural ingredient of animal origin, practically devoid of allergenic properties. The second most popular material from which capsules are made is hydroxypropyl methylcellulose (HPMC), which also does not pose a threat to human health.

How long does a capsule take to dissolve?

• The dissolution time of a capsule depends on its composition and physiological conditions, but usually ranges from a few to several minutes.

Can capsules be chewed?

• Chewing capsules is not recommended because the shell protects the active substance and ensures its proper release in the body.

Bibliography

1. Dobrzyński, Ł. J., Zagoda, M. M. (2010). Natural biopolymers as excipients in the technology of a dosed drug form of the capsule type. Part I. Soft gelatin capsules as a modern and effective form of a medicinal product. Polimery w Medycynie, 40(2), pp. 11-19.
2. Haznar, D., & Garbacz, G. (2009). Selected aspects of modified-release drug technology. Farm Pol, 65(10), pp. 747-757.
3. Bauer, K.H., Frömming, K.-H, Führer C. (2011). Drug dosage form technology with elements of biopharmacy. Wrocław: MedPharm Polska.
4. Pluta, R., Jankowski, A., & Han, S. (2009). Soft capsule production technology. Farm. Przegl. Nauk, 1, 28-31.
5. https://www.efsa.europa.eu/en/efsajournal/pub/5047