Capsule fillers, as an important component of drug formulations, play a crucial role in ensuring drug efficacy and safety. The following is a detailed introduction to capsule fillers:

　　I. Definition and Classification

　　Capsule fillers are substances used to fill the inner space of capsules. Their purpose is to protect drug ingredients, improve drug palatability, enhance drug stability, and improve bioavailability. Depending on their composition and properties, capsule fillers can be classified into several types, including but not limited to sugars (such as sucrose, lactose), starches (such as corn starch, potato starch), celluloses (such as microcrystalline cellulose), and oils (such as hydrogenated soybean oil).

　　II. Common Capsule Fillers and Their Properties

　　Sugars: Sugar fillers have good solubility and palatability, often used to improve the sweetness and taste of drugs. However, for special populations such as diabetic patients, the use of sugar-containing fillers should be avoided.

　　Starches: Starch fillers are inexpensive, widely available, and have good dilutability and stability. They can increase the volume of the drug and improve its flowability, facilitating capsule filling and preparation.

　　Celluloses: Cellulose fillers, such as microcrystalline cellulose, not only have good dilutability and stability but also have lubricating and disintegrating properties. In capsule formulations, they can improve drug solubility and release rate, thereby increasing bioavailability.

　　Oils: Oil fillers, such as hydrogenated soybean oil, are commonly used as lubricants in tablets and capsules, reducing friction and adhesion between drug particles and improving flowability. In soft capsule formulations, hydrogenated soybean oil can also be used as a filler to protect drug components from external environmental influences.

　　III. Application and Selection

　　When selecting capsule fillers, the properties of the drug, patient needs, and formulation process requirements must be considered comprehensively. For example, for drugs that require controlled drug release, fillers with sustained-release effects can be selected; for drugs with high palatability requirements, fillers with good palatability can be selected. Furthermore, the compatibility of the filler and drug components must be considered to avoid adverse reactions.

　　In summary, capsule fillers play an important role in drug formulations. Through the rational selection and application of different types of fillers, safe, effective, and palatable capsule formulations can be prepared to meet the therapeutic needs of patients.