Troubleshooting Guide – TOP 10 Tableting

Horizontal splitting of tablet at the top (capping) or anywhere but the top (lamination)

Possible reason:

• Too many fine particles in the granulate
• Separation of the granulate
• Too much of hydrophobic lubricant
• No suitable lubricant
• Not enough or not suitable binder
• Low moisture content
• API content too high
• Compression force too high
• Speed of the tablet press too high
• Too much air trapped in the pre-compression
• Tablet press tool defective

Remedy: 

• Change the quantities in the granulate
• Use enough and an efficient binding agent
• Adjust used lubricant
• Add adsorbent agent
• Moisturize or dry the granulates
• Reduce amount of API
• Adjust the pressure for compression (use pre-compression)
• Decrease speed of the tablet press
• Use more suitable punches (conical)

Granulate of a formulation is sticking to the face of the press punch

Possible reason:

• The granulate was not completely dried
• Lubricant content too low
• Too much binder used
• Oily or waxy materials used
• Too soft or weak granulates
• Compression too high or too low
• The product became too warm
• Rough or scratched punch faces

Remedy:

• Completely dry the granulate
• Use enough and an efficient lubricant
• Add suitable binder
• Modify mixing process and add an absorbent
• Adjust the compression force
• Produce a thinner tablet (height)
• Polish the surface of the punch

Small, fine cracks observed on the upper and lower surface or on the sidewall

Possible reason:

• The granulate is too large
• The granulate is too dry
• Tablets expand
• Granulation too cold
• Tablet expands on ejection due to air entrapment

Remedy:

• Reduce granulate size by adding more fine particles
• Moisturize or dry the granulate and add binder
• Improve granulation, add dry binders
• Adjust ambient temperature
• Use conical die

Occurs when the edges of the tablets break during the press process or during the handling and coating

Possible reason:

• Sticking on punch faces
• Too dry granulate
• Too much binding causes chipping at bottom
• Edge of punch face turned inside/inward
• Concavity too deep to compress properly

Remedy:

• Use suitable binding agent or use dry binders
• Dry the granulate properly or increase lubricant
• Add hygroscopic substances
• Reduce concavity of punch faces
• Use flat punches
• Polish the punch edges

The term is used when the tablets adhere, seize, or tear in the die

Possible reason:

• Too much moisture in the granulate
• Too little lubricant in the granulate
• Granulate too hard for the lubricant to be effective
• Granulate material sticks to the die
• Punch is not suitable anymore

Remedy:

• Increase drying time of the granulate
• Use enough and an efficient lubricant
• If too warm, reduce temperature
• Increase space for ejection
• Replace punch

High variation of tablet weight

Possible reason:

• High variation in granulate density
• Die not completely filled
• High variation of granulate particle size
• Flowability insufficient
• Press speed too high / filling time too short

Remedy:

• Weight differences can be reduced by granulation and compaction
• Avoid free fall of the granulate (to prevent decomposition)
• Use flowing enhancers to optimize flowability of the granulate or powder blend
• Reduce press speed / increase filling time

Tablet breaks during ejection or handling of the tablets

Possible reason:

• Variation in bulk density
• Inhomogeneity of granulate particle size
• Tablet hardness varies with the weight of the tablet
• The ejection blade is too old or damaged

Remedy:

• Achieve homogeneous bulk density
• Use enough and an efficient binding agent
• Control the tablet weight
• Use suitable ingredients for good compacting properties
• Increase the compression force
• The eject blade must be checked or replaced

High degree of abrasion after mechanical stress

Possible reason:

• Too large particles in the granulate break apart at higher compression forces
• Entrapped air can cause the tablet to break apart
• Tablet breaks during ejection
• Lower compression may not be enough to bind particles together

Remedy:

• Powder should be more cohesive
• Use enough and an efficient binding agent
• Use suitable binders
• Control tablet weight
• Slowing the press will extend dwell time and give the air more time to escape
• Control settings on tableting machine
• Check tableting tool

Is used to describe an inhomogeneous distribution of color in a tablet

Possible reason:

• A colored drug used along with colorless or white-colored excipients
• A dye migrates to the surface of granulate while drying
• Improperly mixed dye, especially during direct compression
• Improper mixing of a colored binder solution

Remedy:

• Use suitable colorants
• Change the solvent system & binder
• Reduce drying temperature and aim for smaller particle size for granulate
• Mix properly and reduce particle size to prevent decomposition
• Incorporate dry color additive during powder blending step, then add fine powdered adhesives and mix properly – finally add granulating liquid

API is not released within required time

Possible reason:

• Too much binder
• No disintegrant
• Too hard compression force used
• No water soluble excipients are used

Remedy:

• Use less binder
• Use disintegrant or superdisintegrant
• Decrease compression force
• Reformulate or use proper disintegrant