i. Diluents:
To increase bulk, e.g. lactose, sorbitol, starch etc.
ii. Absorbents:
Eutectic or hygroscopic drug need absorbent for, e.g. oxides and carbonates of magnesium and calcium.
iii. Glidants:
To ensure a regular flow of powder, e.g. talc and magnesium stearate.
iv. Antidusting agents:
During filling of capsule in automatic filling machine a lot of dust comes out to avoid this Antidusting agent added e.g. inert oils.