The Common Problems for Manufacturing Tablet

1. Introduction

Tablet manufacturing is one of the most complex processes in the pharmaceutical industry. A single defective tablet not only leads to production losses but can also impact patient safety and compliance. Understanding the most frequent tablet defects is essential for manufacturers to identify their causes and take corrective measures. This article highlights the most common defects in tablets, their possible reasons, and practical solutions.

2. Common Issues in Tablet Production

In tablet manufacturing, several common defects can occur, each with specific causes and corresponding solutions. One of the most frequent problems is capping and lamination, where tablets either split at the top (capping) or within their layers (lamination). This typically results from excess fine particles, poor binding, air entrapment, or overly high compression speed. To address this, manufacturers often optimize granulation, add more effective binders, reduce press speed, or introduce a pre-compression step.

Another issue is cracking, where fine cracks appear on the surface or edges of tablets. This defect usually arises when granules are too dry or too large, or when stress occurs during ejection and under temperature fluctuations. Proper moisture adjustment, improved binder selection, optimized granulation, and stable environmental controls can effectively reduce this problem.

Chipping, where tablet edges break during handling or coating, is generally caused by weak binding, excessively dry granules, or worn punches. Solutions include increasing binder strength, controlling granule moisture, and maintaining or replacing tooling through polishing.

Binding is another concern, occurring when tablets stick to the die during ejection. This often results from excess moisture, insufficient lubrication, overly hard granules, or damaged tooling. Extending the drying process, using efficient lubricants, replacing punches, and reducing compression temperature are typical remedies.

Weight variations within the same batch pose consistency issues. These are usually due to poor powder flowability, wide particle size distribution, or incomplete die filling. Manufacturers can mitigate this by improving granule uniformity, adding flow-enhancing excipients, or lowering the press speed for more accurate filling.

In some cases, tablets experience poor disintegration, meaning they fail to dissolve within the required time frame. This happens when too much binder is used, disintegrants are absent or insufficient, or compression force is too high. The solutions include reducing binder amounts, adding super-disintegrants, and optimizing compression force.

A related problem is low friability resistance, where tablets break or abrade easily under stress. Entrapped air, large granules, and weak cohesion are the primary culprits. To overcome this, manufacturers may use more cohesive binders, refine the granulation process, and extend dwell time during compression.

Hardness variation is another common defect, leading to inconsistent tablet strength. Uneven granule distribution, variable compression force, and worn ejection blades are usually responsible. Ensuring uniform mixing, adjusting compression parameters, and maintaining tooling can resolve this issue.

Sticking and picking occurs when material adheres to punches or when coating pulls away core particles. This is often linked to moisture imbalance, excess binder, poor drying, or the use of flat-faced tablets. Improvements in drying processes, balancing binder levels, polishing tooling, or adjusting coating drum speed can help minimize sticking and picking.

Lastly, mottling refers to uneven color distribution in tablets. It is generally caused by dye migration, poor mixing, or unsuitable drying conditions. To address this, stable colorants should be selected, mixing processes should be thorough, and drying temperatures should be carefully controlled.

 3. Conclusion

Tablet production involves multiple steps where things can go wrong, resulting in defective tablets. By understanding common tablet defects such as capped tablets, cracking, sticking and picking, and mottling, manufacturers can implement preventive measures and maintain consistent product quality. Addressing these defects in tablets early not only ensures regulatory compliance but also safeguards patient trust and treatment effectiveness.