Additives and Excipients Used in Tablet Formulation

In tablet formulation, additives, and excipients play critical roles to ensure the desired characteristics of the final product. These substances are generally pharmacologically inactive but are crucial for the manufacturing process, stability, and bioavailability of the active pharmaceutical ingredient (API). Here’s a categorized list of various excipients used in tablet formulations, along with examples: 

1. Diluents (Fillers)

• Function: Increase the bulk of the tablet, making it easier to handle and compress.
• Examples:
  • Lactose
  • Microcrystalline cellulose (MCC)
  • Starch
  • Dicalcium phosphate
  • Mannitol
  • Sorbitol

2. Binders (Adhesives)

• Function: Promote cohesion among the powder particles to form granules and ensure the tablet remains intact.
• Examples:
  • Polyvinylpyrrolidone (PVP)
  • Starch
  • Gelatin
  • Hydroxypropyl methylcellulose (HPMC)
  • Acacia gum
  • Pregelatinized starch

3. Disintegrants

• Function: Promote the breakup of the tablet into smaller fragments in the digestive tract for easier dissolution and absorption.
• Examples:
  • Sodium starch glycolate
  • Cross-linked PVP (Crospovidone)
  • Croscarmellose sodium
  • Starch
  • Microcrystalline cellulose (MCC)
  • Alginic acid

4. Lubricants

• Function: Reduce friction during tablet ejection and prevent the tablet from sticking to the punches and dies during production.
• Examples:
  • Magnesium stearate
  • Stearic acid
  • Talc
  • Sodium stearyl fumarate
  • Hydrogenated vegetable oils

5. Glidants

• Function: Improve powder flowability by reducing interparticle friction.
• Examples:
  • Colloidal silicon dioxide
  • Talc
  • Magnesium stearate
  • Corn starch

6. Anti-adherents

• Function: Prevent the formulation from sticking to the equipment.
• Examples:
  • Talc
  • Magnesium stearate
  • Corn starch
  • Sodium lauryl sulfate

7. Preservatives

• Function: Prevent microbial contamination and extend shelf life.
• Examples:
  • Methylparaben
  • Propylparaben
  • Sodium benzoate
  • Benzoic acid

8. Coloring Agents

• Function: Provide color to improve tablet appearance and aid in identification.
• Examples:
  • FD&C dyes (e.g., FD&C Yellow No. 6)
  • Titanium dioxide
  • Iron oxides

9. Flavors and Sweeteners

• Function: Improve the taste and acceptability, especially for chewable or orally disintegrating tablets.
• Examples:
  • Aspartame
  • Saccharin sodium
  • Sucralose
  • Xylitol
  • Sorbitol

10. Film-Coating Agents

• Function: Improve tablet appearance, protect from environmental factors (moisture, light), and mask unpleasant taste.
• Examples:
  • Hydroxypropyl methylcellulose (HPMC)
  • Polyethylene glycol (PEG)
  • Ethylcellulose
  • Methacrylic acid copolymers
  • Polyvinyl alcohol (PVA)

11. Plasticizers

• Function: Provide flexibility to the film coatings and improve the durability of the tablet coating.
• Examples:
  • Glycerin
  • Triacetin
  • Polyethylene glycol (PEG)
  • Dibutyl sebacate

12. Buffers and pH Modifiers

• Function: Maintain the desired pH for drug stability and absorption.
• Examples:
  • Citric acid
  • Sodium citrate
  • Sodium bicarbonate
  • Magnesium oxide

13. Surfactants (Wetting Agents)

• Function: Improve the wetting and solubility of hydrophobic drugs.
• Examples:
  • Sodium lauryl sulfate (SLS)
  • Polysorbates (e.g., Tween 80)
  • Lecithin

14. Stabilizers

• Function: Protect the API from degradation due to factors like heat, light, and moisture.
• Examples:
  • Ascorbic acid
  • Butylated hydroxyanisole (BHA)
  • Butylated hydroxytoluene (BHT)

15. Solvents (for granulation or coating)

• Function: Used during the manufacturing process, particularly for wet granulation or coating.
• Examples:
  • Water
  • Ethanol
  • Isopropanol
  • Methylene chloride (for certain coatings)

These excipients collectively contribute to the overall efficacy, stability, manufacturability, and patient acceptability of tablets.