capsulation

Capsulation is the process of forming a capsule or enclosing material within a capsule. The term derives from the Latin capsula meaning small box. In biology and medicine, capsulation most often refers to the development or presence of a capsule around a cell or particle.

Bacterial capsules are well-defined, gelatinous layers outside the cell envelope composed of polysaccharides, polypeptides, or polyglutamic acid. They differ from a slime layer in density and organization. Capsules protect bacteria from desiccation and from host immune defenses, facilitate adherence to surfaces, and can contribute to virulence. Encapsulated bacteria are often identified by the Quellung reaction. Examples include Streptococcus pneumoniae, Klebsiella pneumoniae, Haemophilus influenzae type b, and Bacillus anthracis.

Capsulation in pharmacology and related fields refers to enclosing an active ingredient within a capsule or microcapsule to control release, protect from degradation, or mask taste. Materials include gelatin, cellulose derivatives, alginates, and natural gums. Techniques include extrusion, coacervation, spray drying, and solvent evaporation. Applications span oral dosage forms with controlled release, nutraceuticals, flavors, and essential oils. Advantages include improved stability and dosing accuracy; disadvantages include higher cost and manufacturing complexity.

In information technology, encapsulation denotes bundling data with methods and restricting access to internal state. While closely related conceptually, the term capsulation is rarely used in this context, with encapsulation being the standard term.