Common Tablet Problems And Solutions

There are varieties of problems that face the pharmaceutical world, some of which we will be discussing as well as solutions that would help solve these problems.

• Overwetting of the tablets/Surface pitting. This is where suspension droplets hit the still wet tablet and the drying air does not dry it enough.
• Physical damages overloading or unloading operation.
• Poor tablet design – flat surfaces.
• Spray Drying. The suspension droplets hit the tablet after the moisture has been removed. This leads to the poor adherence of the coat.

Colour Variation

• Causes and Solutions:
  • Less coats applied – increase the coating.
  • Inadequate tablet mixing during the coating process- increase the pan speed or improve the baffle system.
  • The solid content of coating liquid is high – decrease the solid content of the coating liquid.
  • Not enough spray guns – increase the number of the spray guns.
  • Poor spray pattern bed distribution – check and make sure that the gun position is correct and that the bed coverage is correct.
  • Slow pan speed – increase the pan speed.

Twinning

• Causes and Solutions:
  • High spray rate – decrease the spray rate while increasing the efficiency atomizing.
  • Slow pan speed – increase the span speed.
  • Incorrect tablet shape – choose a new tablet shape to prevent the probability of flat surfaces coming in contact during coating application.
  • Tacky coating formula – reformulate the suspension.
  • Spray gun is close to the tablet bed – increase the distance of the gun to the bed.

Cracking

• Causes and Solutions:
  • Not enough plasticizer/pigmentation or low mechanical strength for coating – check the formulation and improve the mechanical strength characteristics.
  • The core has different thermal expansion than coating – avoid the use of mineral type as fillers whenever possible (ex: carbonate, calcium sulphate).
  • Extended core elastic recovery after submitting it for compaction – extend the holding period of the tablet before the coating process.

Peeling

• Causes and Solutions:
  • Short mechanical strength of coating – choose the formulation with improved strength.
  • Poor adhesion properties of coating to the tablet surface – choose the formulation with improved adhesion features.
  • Extra lubricant use in the formulation – choose an excipient with excellent lubricating properties such as Starch 1500.

Orange Peel Roughness

• Causes and Solutions:
  • High viscosity of the coating solution – decrease the solid content of the coating liquid.
  • Poor atomization of the coating liquid – increase the atomizing air pressure or volume.

Logo Bridging

• Causes and Solutions:
  • Not enough adhesion of the film coating – choose the formulation that would improve the adhesion characteristics.
  • Product’s surface characteristics – reformulate the core formulation to include more coating, hydrophilic ingredients when possible.
  • Inappropriate logo design – choose a different logo design
  • Insufficient plasticizer in the film or high internal stress – decrease the spray rate while increasing the drying rate.

Picking/Sticking

• Causes and Solutions:
  • High spray rate – decrease the spray rate.
  • Improper drying condition – increase the drying condition.
  • Slow pan speed – increase the pan speed rate.
  • Insufficient atomization of coating – increase the atomizing air pressure and volume liquid.
  • Improper distribution of coating liquid – choose the formula that would improve the adhesion characteristics.

LOGO Infilling

• Causes and Solutions:
  • Inapt logo design (too fine or detailed) – choose a different logo design.
  • Disappearance or erosion of logo design due to the tablet surface – decrease the potential of erosion by reformulating the core, changing the logo or modifying the tablet’s surface.
  • Logo bridging – see solution provided for logo bridging.
  • In-filling of the logo with spray dried coating material – decrease the spray drying by:
    • Decreasing atomizing air pressure
    • Decreasing distance between the spray gun and tablet bed surface
    • Decreasing inlet air flow or air temperature
    • Increasing spray rate

Core Erosion

• Causes and Solutions:
  • High friability rate/inherent softness – improve the mechanical strength core through:
    • increasing the core impaction force
    • Modifying the core formulation
    • Changing the core process
  • High pan speed during coating process – decrease the pan speed.
  • Insufficient solid content in the spray – choose formulation with high solid solution.
  • Low spray rate – increase the spray rate.
  • Untimely swelling of the hydrophilic disintegrant in the formulation – switch the super disintegrant with less hydrophilic super disintegrant ex: Starch 1500.

Edge Chipping/Erosion

• Causes and Solutions:
  • Low mechanical strength of coating – choose the formulation with improved mechanical strength.
  • Unwarranted pan speed – reduce pan speed.
  • Low solid content in the coating liquid – increase the solid content.
  • Low spray rate – increase the spray rate.
  • Sharp tablet edges – modify the tablet punch design.
  • Worn tablet punches – replace or refurbish tablet punches.
    • Low tablet friability/hardness – modify the mechanical strength of the core through increase of the compaction force.
    • Modify tablet shape.
    • Reformulate tablet formulation.
    • Change the process how the core is produced.