Capsules refer to the dosage forms of medicines filled in empty capsules in divided doses, mainly for oral administration. Capsules are divided into hard capsules and soft capsules.

    The drugs in hard capsules are in powder or granular form, do not contain binders, dissolve faster in gastrointestinal fluids, and are easier to absorb. Especially for poorly soluble drugs, if the microcrystalline or fine powder is made in advance, the original physical state and crystal form can be maintained in the capsule, which can improve the bioavailability. A few drug capsules that require enteric coating are prepared and processed into enteric-coated capsules. Some drugs are pre-made into slow-release granules or microcapsules and then filled in capsules to become slow-release capsules, in addition to quick dissolving capsules and effervescent capsules.

    The material for making hard capsule shells (empty capsules) is mainly gelatin. The empty capsule is divided into two sections, which are tightly nested, and the quality is required to be tough, not prone to sticking, soft, cracking, mildew, and other phenomena, and the thickness is uniform.

    Soft capsule, also known as the capsule, is made of gelatin, glycerin (or some sorbitol), water, etc. to make plastic rubber. Add oil-like medicine or semi-solid oily medicine in the middle of two rubber sheets, and press them into capsules in a pill-making machine. The quality of softgels should remain elastic for a long time.