Introduction to Capsules

A solid dosage form of drugs, also known as wafer capsules, typically made from rice paper.

Two plate-shaped rice paper pieces hold the dry powder medicine (up to 2g).

Cachets are made from rice flour.

Mixing rice flour and water, then molding it between heated cylinders. The water evaporates, forming the wafer.

Cachets require dipping in water and swallowing with a lot of water to prevent tasting the medicine.

Easy to make; Disintegrates quickly in the stomach; Can handle large doses.

Easily damaged; Needs softening before swallowing; Not protected from light/moisture; Not suitable for large-scale production.

Rarely used now.

A solid dosage form containing medication, enclosed in a soluble shell (gelatin).

A capsule shell made of gelatin, typically filled with powders or granules.

A flexible capsule shell, containing liquids, solutions, or suspensions.

Capsule sizes are numbered (000 largest to 5 smallest) based on their capacity for granules.

A hard gelatin capsule consists of a cap (shorter) and a base (longer) portion that fit together.

Hard gelatin capsules are filled with powders or pellets, while soft gelatin capsules can contain liquids or solutions.

Capsules are made of materials like gelatin that are tasteless, colorless, and often clear.

Capsules offer a way to package, deliver, and protect medicines efficiently, by administering the compounds and preventing drug degradation.

Capsules are classified into Hard and Soft based on their flexibility and construction. Hard capsules have two parts (body and cap) and are less flexible, while Soft capsules are one piece, more flexible, and often used for liquids.

Soft capsules offer advantages like ease of swallowing, taste masking, rapid drug release, and fewer excipients needed.

Soft capsules are typically used for oral medications, especially liquids, dispersions, oils, and pastes.

Challenges with Soft capsules include specialized manufacturing, limited excipient choices, potential stability issues, uneven fill weight, and inability to divide doses.

Soft capsules are not suitable for strongly efflorescent drugs (losing moisture), strongly deliquescent powders (absorbing moisture), or very soluble salts, due to potential capsule shell changes.

Capsules are typically made from gelatin, a protein derived from animal collagen, and other materials to achieve the desired properties.

Capsules act as a protective shell for medications, ensuring controlled release and masking unpleasant taste or odor.

Capsules are a popular dosage form due to their ease of administration, versatility in filling, and ability to mask unpleasant characteristics of medications.

Gelatin is a natural protein derived from collagen, mainly found in animal bones and skin. It's used in a variety of applications like food and medicine.

There are two main types of gelatin: Type A, produced by acid hydrolysis (from animal skins), and Type B, produced by basic hydrolysis (from bones).

The Bloom strength of gelatin is a measure of how rigid its gel is. It indicates how strong and firm the gel will be.

Viscosity refers to the thickness or resistance to flow of a gelatin solution. It's important for controlling the thickness of films, sheets, and capsules.

Hard gelatin capsules are made by dipping molds into a gelatin solution, allowing them to set and dry. The bodies and caps are then joined to form the capsule.

Gelatin capsules typically contain 14-16% water during formation. This water content is important for the mechanical properties of the capsule.

After filling with drugs, gelatin capsules are dried further to a 13% water content. This ensures the capsule doesn't crack or deform.

Soft gelatin capsules typically contain 5-14% water by weight. This helps maintain flexibility and prevents brittleness during manufacturing and storage.

Preservatives like parabens and benzoic acid are sometimes added to soft gelatin capsules to prevent microbial contamination during manufacturing and storage.

Plasticisers like glycerol and sorbitol are added to gelatin to increase flexibility. Soft gelatin capsules have a higher proportion of plasticiser than hard gelatin capsules.

Colourants, often synthetic dyes or pigments, are used in gelatin capsules to enhance their appearance and help identify the product.

Titanium dioxide is a white pigment used in capsules as an opacifying agent, making them opaque and blocking light.

Iron oxides are pigments used in capsules to create various colours like black, red, and yellow. They are insoluble pigments, meaning they do not dissolve in the capsule shell.

Wetting agents like sodium lauryl sulphate are added during the preparation of gelatin capsules to improve their ability to mix with water.

Soft gelatin capsules are designed to be flexible and pliable because they contain higher levels of plasticisers.

The process of filling capsules with a mixture of active ingredients, diluents, and additives in powdered form.

Substances like magnesium stearate that are added to powder mixtures to improve their flowability and ensure consistent filling of capsules.

Substances like starches or cellulose that help the powder mixture to break down and dissolve quickly in the body for optimal drug release.

Filling capsules with substances other than powders, such as liquids, granules, pellets, or semisolids.

Liquids used for filling capsules must be non-aqueous, meaning they cannot contain water. Examples include oils and polyethylene glycols.