Validating rapid micro methods
The membrane is scanned by a laser, fluorescent light is detected, and a membrane scan map is produced which captures the position of each fluorescent event, which is then verified by visual examination using an epifluorescent microscope.
The third type of RMM is cell component analysis or indirect measurement; expression of certain cell components correlates to microbial presence.
Use of a rapid method as an alternative to the traditional sterility method requiring 14 days has several advantages.
A shorter incubation minimizes the time needed for recovery of microbial contaminants, enabling more rapid implementation of corrective actions that would prevent cross contamination to other product batches and can reduce product release time.
Over the course of several years, efforts led to incubation times being harmonized to 14 days in 2004, and by 2009 (USP 32) the remaining portions of the sterility test were harmonized with only a few exceptions.
In 2010, a leading pharmaceutical company implemented a rapid sterility method consisting of a five-day incubation as compared to the traditional 14-day incubation.
The ATP bioluminescence technology system was selected because it is growth based, uses membrane filtration which is similar to the compendial method, and can detect one colony-forming unit (cfu) following incubation.
One example is amplification of DNA or RNA by polymerase chain reaction (PCR).
RMMs can be qualitative (presence/absence) or quantitative (enumeration), destructive or nondestructive, and can be applied to filterable or non-filterable products.