Capsule pills, tablets, etc. need to add the excipients during the manufacturing process. Sometimes the amount of excipients even are greater than the main drug. In the preparation of the capsule drug, in addition to the main drug powder, an additional agent such as a diluent, a lubricant, a disintegrator or the like are added as needed. These add-on agents together with the drug affect the disintegration of the capsule and the release of the main drug.

Excipients are the basis of raw material, and also have an important impact on the pill making process, stability, safety, product quality and efficacy of the capsules.

Picture by Marco Verch from flickr

In the selection of excipients, the following principles need to be followed:

• 1. Excipients need to increase the physical and chemical stability of drugs and empty capsules. It ensures that the drug is not affected by changes in heat, light, and humidity, and maintains a stable pH range.
• 2. The mixture obtained after mixing the excipients with the drug should have proper fluidity and dispersibility so that it can be filled into capsules and will not stick together when exposed to water.
• 3. The addition of excipients for special capsules such as enteric capsules should take into account the control of drug release time.
• 4. The safety of excipients for capsule drugs cannot be ignored. The added excipients should not add to the toxic side effects of the drug, and preferably improve the quality of the drug.