Liquid Immersion Microbial Challenge Tests: Microbial Testing for Container Closure Integrity

Liquid Immersion Microbial Challenge Tests: Microbial Testing for Container Closure Integrity
Introduction
The container closure system for pharmaceutical products intended to be sterile is critical and this criticality relates to the physical properties of the container closure system in that a poorly designed or manufactured system will result in microbiological penetration. Factors to take into account with, for example, rubber-stoppered glass vials include having the correct dimensional specifications for the internal diameter of the neck opening and its depth, the internal and external diameters of the flange. Other factors are the concentricity of the flange, the neck and the body of the vial. Any angularity of the flange versus the vertical center line of the vial must be specified; so must the physical finish of the surface of the flange and internal neck bore to ensure satisfactory mating with the closure. Closures must be specified in terms of diameters, depth, thickness and elasticity.