The Pharmaceutical Capping Process-Correlation between Residual Seal Force, Torque Moment, and Flip-off Removal Force

Area of Science:

• Pharmaceutical Manufacturing
• Container Closure Integrity
• Process Engineering

Background:

• Parenteral drug products commonly use glass vials with elastomeric stoppers and crimp caps.
• Vial sealing is critical for final product quality, affecting container closure integrity.
• Current visual inspection for crimp cap defects is subjective and labor-intensive.

Purpose of the Study:

• To investigate the torque moment required to turn crimp caps.
• To measure the force needed to remove the flip-off button.
• To establish correlations between capping parameters, residual seal force, and seal quality.

Main Methods:

• Sealing container closure systems with varying capping equipment settings and residual seal forces.
• Measuring crimp cap torque moment and flip-off button removal force.
• Analyzing the influence of vial head diameter, stopper type, and crimp cap type.

Main Results:

• A significant correlation was established between torque moment and residual seal force.
• Torque moment is influenced by vial head diameter, stopper type (serum vs. lyophilized), and crimp cap type (West® vs. Datwyler®).
• Capping process did not influence flip-off button removal force, but could detect partially crimped vials.

Conclusions:

• A controlled capping process with a defined residual seal force range ensures a tight crimp cap.
• This optimized process enhances container closure integrity and overall product quality.
• Establishing torque moment as a quality indicator can improve efficiency and reduce subjectivity in inspections.