What is the role of Avicel in a capsule formulation?

• A. Lubricant
• B. Filler
• C. Binder
• D. Disintegrant

Answer: (B)

In capsule formulations, Avicel serves as a bulking agent to provide the necessary fill volume. Microcrystalline cellulose (Avicel) is inert, biocompatible, and has excellent flow and packing properties, which help achieve uniform fill weight and consistent dosing when the powder is loaded into capsules. It is not a lubricant (which reduces friction during filling and ejection), not a disintegrant (which promotes tablet disintegration in the GI tract), and not primarily a binder in this context (binders are more relevant to compressed tablets). While some MCC grades can act as binders in certain processes, its main role in capsules is to act as a filler to add bulk and improve flow for reliable capsule filling.