Common Blister Defects in Pharmaceutical Packaging: Identification and Solutions

Blister packaging is a popular choice in the pharmaceutical industry due to its ability to safeguard products, enhance usability, and ensure tamper-proofing. However, defects during blister packaging can compromise the product’s quality, create regulatory issues, and inflate operational costs. This article dives into the various defects that can occur in blister packaging, their potential causes, and the measures that can help avoid them.

Types of Blister Defects

1. Forming Issues

• Pinholes or Cracks: Tiny perforations or fractures in the blister material, compromising the seal.
• Improper Cavity Formation: Misshapen or underdeveloped cavities due to incorrect forming settings.
• Distorted Blisters: Deformation caused by inadequate heat or pressure during the forming process.

2. Sealing Problems

• Weak Seals: Poor adhesion between the blister film and the lidding foil, leading to product contamination.
• Seal Gaps or Leakage: Incomplete sealing, often caused by uneven pressure or insufficient heat.
• Overheating: Excessive heat during the sealing process, which may result in foil degradation.

3. Printing Errors

• Misalignment: Printed information, such as batch numbers or expiry dates, is out of place.
• Smudging or Fading: Illegible print due to improper ink application or drying issues.

4. Product Placement Defects

• Misplaced Products: Tablets or capsules that do not align with blister cavities.
• Empty Cavities: Missing products in the formed cavities, leading to incomplete packs.
• Damaged Units: Tablets or capsules that break or crumble during the packaging process.

5. Visual and Aesthetic Defects

• Scratches or Abrasions: Surface marks caused by rough handling or mechanical wear.
• Cloudy Film (Fogging): Loss of clarity in the blister film, making the product less visible.
• Contamination: Presence of foreign particles within the blister, compromising product safety.

Causes of Blister Defects

1. Material-Related Issues:
   • Using low-quality films or foils with inconsistent thickness or properties.
   • Incompatibility between the product and the selected packaging material.
2. Machine-Related Problems:
   • Improper calibration or maintenance of packaging equipment.
   • Worn-out dies, molds, or sealing heads.
3. Environmental Factors:
   • High humidity or temperature fluctuations that impact material flexibility and sealing strength.
4. Human Errors:
   • Incorrect machine setup or material loading.
   • Skipping quality checks during production.
5. Product Characteristics:
   • Fragile tablets or irregularly shaped capsules that are more prone to damage.