Pharmaceutical capsules are divided into two types, stomach-soluble and enteric-coated. Generally, stomach-soluble capsules will melt in half an hour, thereby releasing the drug and achieving the purpose of treatment. But enteric-coated capsules do not melt in the stomach, only when they enter the intestine, and the melting time is very fast.

    We know that the commonly used capsules have color and no color, and the pigments added to the capsule shell are all medical pigment additives stipulated by the state, which are not harmful to the human body. The pigment components of the capsule shell are food pigments, such as carmine, amaranth, lemon yellow, olive green, etc.

    Capsule color has the following two functions: First, it looks good on the senses, which can cover up the appearance of the drug itself. Some colorists also say that colors can help patients with different diseases and assist in psychological treatment. The second is the different colors, which are for the purpose of simply distinguishing the medicines, and the purpose is to facilitate the identification. Another point is shading, which is used as a sunscreen. For example, for some light-sensitive drugs, titanium dioxide can be added to the capsule as a sunscreen.