JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm.D III Year PHARMACEUTICAL FORMULATIONS Previous Question Paper (January/February - 2021 - R08)

Tablets are solid dosage forms containing one or more medicinal substances with or without suitable diluents, prepared by either compression or molding methods. They are the most popular oral dosage form due to their convenience, accuracy of dosage, and stability.

Tablet excipients and their functions include:

• Diluents/Fillers: Used to increase the bulk of the tablet to ensure a convenient size for compression (e.g., Lactose, Microcrystalline cellulose).
• Binders/Adhesives: Promote granule formation and ensure the tablet remains intact after compression (e.g., Starch paste, PVP).
• Disintegrants: Facilitate the breakup of the tablet into smaller particles upon contact with water (e.g., Sodium starch glycolate, Croscarmellose sodium).
• Lubricants: Reduce friction between the tablet surface and the die wall during ejection (e.g., Magnesium stearate, Talc).
• Glidants: Improve the flow properties of the powder mixture from the hopper to the die cavity (e.g., Colloidal silicon dioxide).
• Anti-adherents: Prevent the powder from sticking to the punch faces (e.g., Talc, Corn starch).
• Coloring and Flavoring agents: Improve the aesthetic appeal and palatability of the formulation.

Granulation is the process of collecting powder particles into larger, multi-particle entities called granules to improve flow, compressibility, and uniformity. The primary techniques are:

1. Wet Granulation: The most common method, involving the addition of a liquid binder (aqueous or solvent-based) to the powder blend to form a damp mass. This mass is screened into granules, dried, and then lubricated for compression. It is ideal for drugs that are moisture-stable.
2. Dry Granulation (Slugging or Roller Compaction): Used for moisture- or heat-sensitive drugs. The powder blend is compressed into large, flat tablets (slugs) or passed through rollers to form a dense sheet, which is then milled and screened to produce granules of the desired size.
3. Direct Compression: A simplified process where the drug and excipients are blended and compressed directly without any prior granulation. This requires excipients with high flowability and compressibility, such as spray-dried lactose or microcrystalline cellulose.
4. Melt Granulation: A technique where a binder that melts at a low temperature is used. The drug and excipients are heated until the binder melts and acts as the granulating agent, eliminating the need for drying steps.