Additives used in compressed tablets

 Here’s a summary of common additives used in the formulation of compressed tablets, along with their functions and characteristics:

1. Binders

• Function: Help in holding the ingredients together, ensuring the tablet maintains its shape and integrity.
• Common Examples:
  • Starch (e.g., corn or potato starch)
  • Polyvinylpyrrolidone (PVP)
  • Hydroxypropyl methylcellulose (HPMC)
• Characteristics: They can improve the mechanical strength of the tablet and assist in the drug's release profile.

2. Diluents (Fillers)

• Function: Increase the bulk volume of the tablet, making it easier to handle and swallow.
• Common Examples:
  • Lactose
  • Microcrystalline cellulose (MCC)
  • Calcium phosphate
• Characteristics: Diluents should be inert and compatible with the active pharmaceutical ingredient (API).

3. Disintegrants

• Function: Facilitate the breakup of the tablet upon ingestion, enhancing drug release and absorption.
• Common Examples:
  • Croscarmellose sodium
  • Sodium starch glycolate
  • Microcrystalline cellulose
• Characteristics: Effective disintegrants swell upon contact with water, creating pressure that helps break the tablet apart.

4. Lubricants

• Function: Reduce friction during tablet compression and prevent sticking to the punch and die.
• Common Examples:
  • Magnesium stearate
  • Stearic acid
  • Talc
• Characteristics: Lubricants must be used in small amounts as excessive use can affect tablet dissolution.

5. Glidants

• Function: Improve the flow properties of the powder blend to ensure uniformity in tablet weight and content.
• Common Examples:
  • Colloidal silica
  • Talc
• Characteristics: Enhances the powder flowability and reduces friction between particles.

6. Coloring Agents

• Function: Provide aesthetic appeal and help in the identification of the tablet.
• Common Examples:
  • Iron oxide
  • Natural colorants (e.g., beetroot powder)
• Characteristics: Must be non-toxic and stable under processing conditions.

7. Flavoring Agents

• Function: Improve the taste of the tablet, especially important for chewable tablets.
• Common Examples:
  • Artificial flavors (e.g., peppermint, vanilla)
  • Natural flavors
• Characteristics: Help mask any unpleasant taste of the API.

8. Coating Agents

• Function: Provide a protective layer over the tablet, which can aid in swallowing, mask taste, and control the release of the drug.
• Common Examples:
  • Hydroxypropyl methylcellulose (HPMC)
  • Ethylcellulose
• Characteristics: Coatings can be functional (for modified release) or decorative.

Conclusion

Each of these additives plays a crucial role in ensuring the effectiveness, stability, and acceptability of compressed tablets. The choice of additives depends on the specific requirements of the drug formulation and the desired properties of the final product. Careful consideration is necessary to optimize the formulation for both manufacturing and patient outcomes.