Common Tablet Defects: Causes and Solutions

Defects in tablet composition are known as tablet defects. Depending on the experience level, the equipment and excipients utilized, produced, or compressed tablets can have specific flaws that may be seen immediately or after storage. Listed below are problems associated with tablet manufacturing by pharmaceutical companies.

1. Lamination and Capping

Capping removes or separates a compressed tablet's top or bottom from the tablet's main body. This could happen when the tablet die is being ejected, or it might happen during processes like coating, packing, or shipping.

A. Causes of lamination and capping

• Lack of appropriate air removal from the granules in the die cavity before and during compression results in air pockets in the granules.
• Excessive fines or microscopic, insignificant particles present in the granules

• Using too much pressure during the compaction stage caused the tablet's elastic compression to be excessive.

• Insufficient particle binding to create cohesive tablets.
• Die bore wear is caused, in part, by rigid inorganic fillers.
• Using outdated punches and dies.
• Using granules that have been too dry or granules with shallow moisture content.
• Granules that have not sufficiently or thoroughly dried.
• A lubricant that is present in excess.
• Created strains due to the compact are clinging to the die wall or punch parts.

B. How are issues with capping and laminating resolved when making tablets?

• Make use of tapered dies that taper outward toward the top of the die to let the air out.
• Modify the granulation processes.
• Through a 100 to 200 mesh filter, remove some or all fines.
• Slow down compaction.
• Pre-compression should be used before the main compression.
• Change the type of binder in the granule or increase its concentration.
• Use reinforced die inserts or wear-resistant steel for the dies.
• Replace the dies and punches or thoroughly polish them.
• Make the granules sufficiently moist.

2. Sticking

Sticking is when a small amount of compact material adheres to the faces of the tooling surfaces. The issue worsens as more material is added to what is already adhered to the punch face, as compacts are frequently created in this tooling station. Upper punches appear to be more prone to the issue.

A. Causes of sticking

• Lubrication that is insufficient or only mildly effective.
• The roughness of the tooling's surface.
• The granulation is just a little bit moist.

B. How to avoid sticking when manufacturing tablets

• Properly combine the lubricant.
• Implement coated tooling.
• Polish punch faces.
• Reduce the granules' moisture content.
• Making the tablet thinner and extending the dwell period can boost hardness by causing moist granules to stick to other grains rather than the punch faces.

3. Picking

When a piece of the tablet sticks to the punch surface and begins to erode from the tablet surface, picking occurs. It is a more precise name for a product clinging inside the characters, logos, or patterns on the punch faces.

A. Causes of picking

• Granules that have not adequately dried are compressed.
• Utilization of scratched punches while compressing tablets.

B. How to avoid picking when manufacturing tablets

• Reduce the granules' moisture content.
• Make the punch face shine.

4. Mottled appearance

This frequently occurs when using colored granules. An uneven color distribution on a tablet with light and dark spots is called mottling.

A. Causes of mottling

• Different from other ingredients is the drug's color
• During the granulation process, dye migration occurs to small or large granules.
• While utilizing a colored adhesive gel solution, an uneven dispersion of color.

B. How to stop mottling when making tablets

• Lowering the drying temperature.
• Reduce the particle size via grinding.
• Modify the system of binders.
• Modify your solvent system.
• Adding the proper coloring agent.

5. Chipping

Occasionally, compacts are discovered to have little chips missing from their edges after being removed from the press or during later handling and coating procedures. This flaw, known as "chipping," may also be brought on by compaction issues that result in tablets that are excessively brittle or too soft (low mechanical strength), in addition to the apparent formulation flaws.

A. Causes of chipping

• Dehydrated granules.
• Poorly finished tablets.
• Punches that have been used up will eventually die.
• Improper machine settings, particularly a too-high ejection take-off plate.
• Handling of compacts after they leave the press is far too harsh.
• The machine's high setting sweeps off the blade.

B. How to stop tablets from being chipped during production

• To make the granules plastic, moisten them.
• Punches need to be polished or replaced.
• Lowering the sweep-off blade's speed.
• The lower punch is being adjusted.

6. Binding in the die

The compact edges that are produced have rough, scored edges due to severe side scraping of the die and strong compact ejection forces.

A. Causes of binding in the die

• High friction in the die wall.
• Lack of lubrication or a flaw.
• Worn out tooling or dies.
• The distance between the lower punch and die bore is too great.
• Granules that are too wet and protrude from the lower punch.

B. How to stop the die from binding when making tablets

• Increase the lubricant's concentration or use the right lubricant.
• Replacement or die polishing.
• Utilize durable dies.
• Properly dry the granules.

7. Embossing

This is due to the tablet's imprint or spur line being unclear.

A. Causes of embossing

• Incorrect punch design.
• Use of excessively coarse granules.
• Granule picking and sticking on punches.

B. How to stop embossing while making tablets

• Rectify the incorrect punch embossing design.
• Granular size reduction

8. Double Impression

Only lower punches with a monogram or other engraving are used in a double impression. During the ejection operation, the punch may leave two impressions on the surface of a tablet. By implementing anti-turning mechanisms for the punches, this can be prevented.

Conclusion -

The pharmaceutical industry presents challenging manufacturing problems and solutions for tablets because the tablets' appearance determines the product's overall quality. With a specific tablet defect solution, the quality of such items can be reduced.

Pharmacist at Staple Pharma