Lubricants are used to reduce the friction between the particles (or powder) or tablets and the die hole wall, so that the tableting force distribution and tablet density distribution can be uniform, so that the compressed tablet can be pushed out of the die hole smoothly At the same time, the required force is reduced, and at the same time, the wear of the die is also reduced.
Lubricating Agent in Tablet
- Magnesium stearate
- Calcium stearate
- Stearic acid
- Purified talc
- Light PEG
- Sodium stearyl fumerate
- Sodium lauryl sulphate
Classification of Lubricants
- Water-soluble (hydrophilic) Lubricant: Sodium stearyl fumerate, Sodium lauryl sulphate, Sodium benzoate etc.
- Water-insoluble (hydrophobic) Lubricant: Magnesium stearate, Stearic acid, Purified talc etc.
Lubricants Percentage
- Magnesium stearate: (0.25 - 1.0)%
- Purified Talc: (2.0 - 5.0)%
- Sodium lauryl sulphate: (1.0 - 3.0)%
- Sodium Stearyl Fumerate: (1.0 - 3.0)%
Lubrication Time
Generally, lubricant mixing time is too short (2-5 minutes) compare to other mixing/blending. It is generally conducted at the final stage of blending just before compression or encapsulation.
Role of Lubricant in Tablet Formulation
Choice of lubricant type and lubricant amount in pharmaceutical formulation play a vital role in tablet sticking, hardness and dissolution. Insufficient lubricant amount may result sticking and excessive lubrication may result low hardness and dissolution retardant.
FDA Recommended Lubricants for Pharmaceutical Machines
- H1 lubricants (Incidental lubricants): these are used for those machine parts which are in direct contact with the product and where there are chances of accidental lubricant contact with the product. H1 Lubricants are on the approved list of the FDA and meet the requirements of CFR 21 178.3570
- H2 lubricants: these are used for machine parts that are not in contact with the product, where there is no chance of lubrication mixing with the product.
- H3 lubricants: used to prevent rust, H3 lubricants are in the approved list of guidelines of 21 CFR.
- Choice of Excipients in Product Development
- Blending in Pharmaceutical Industry
- Drug-Excipient Database
