What is a capsule?

In biology, a capsule is a layer of polysaccharides that surrounds the cell wall of some bacteria. It is composed of complex carbohydrates, such as glucose, galactose, and mannose, and is synthesized by the cell. Capsules are important for protecting bacteria from environmental stresses, such as desiccation, temperature extremes, and exposure to harmful chemicals. They also play a role in adhesion to surfaces, nutrient acquisition, and colonization of host tissues. In addition, capsules can interfere with the immune system of the host, making it easier for bacteria to cause disease.

In the pharmaceutical industry, a capsule is a solid dosage form that consists of a small, cylindrical-shaped container made of gelatin or another suitable material. Capsules contain a powdered or liquid drug or combination of drugs, and are taken orally. The gelatin capsule dissolves in the stomach, releasing the drug for absorption. Capsules are often used to deliver drugs that have an unpleasant taste or odour, or that are sensitive to stomach acid.