1. Capsules are solid dosage forms that enclose medications within gelatin shells. They can contain powders, liquids, or semisolids.
2. There are two main types - hard gelatin capsules that have two pieces joined together, and soft gelatin capsules that are one solid piece.
3. Capsules offer advantages like masking taste, easy administration, and low manufacturing costs. Their main disadvantage is that some liquids or solutions can dissolve the gelatin shell.