Testing For Microbial Ingress Is Over

The microbial ingress test has long been a staple in parenteral (vial, syringe, etc.) container closure integrity testing. There is no single approach to microbial ingress, varying from site to site. It involves taking container samples and placing them in a microbial soup, potentially cycling pressures to drive microbes into the container. If there are defects in the range of microbial ingress, the microbes would flourish inside the vial. The method is cumbersome, time consuming, but most importantly highly probabilistic. For decades the FDA used this as a gold standard of CCIT and sterility of the container. The test method was a longtime fixture in drug filings and package validation, yet the poor effectiveness and the probabilistic nature of the method was well understood. USP 1207 is now driving the FDA and the drug companies away from this method, and towards deterministic methods such as HVLD and Vacuum Decay. The days of microbial ingress testing are over.