Capsules

The two main types of capsules are: Hard-shelled capsules, which contain dry, powdered ingredients or miniature pellets made by e.g. processes of extrusion or spheronization. These are made in two-halves: a smaller-diameter "body" that is filled and then sealed using a larger-diameter "cap".

Generally, hard-shelled capsules contain powdered medication, but sometimes they contain liquid. Soft-shelled capsules are often made of gelatin and contain liquid medication, like in the case of “liquigels.”

Capsules have a significant role in determining access of certain molecules to the cell membrane, mediating adherence to surfaces, and increasing tolerance of desiccation.