Sterility Assurance with Filtration Taking Bioburden, Membrane Integrity, and Process Conditions into Account

LEVEL: INTERMEDIATE U nder ideal conditions, the result of a sterility test reflects the presence or absence of viable organisms in the samples analyzed. However, it has long been recognized that inferences regarding sterility (whether for a batch of inprocess material or a finished dosage form) are subject to statistical limitations. The probability (P) of detecting contamination in a given batch of finished product by performing a 20-unit sterility test can be estimated using the equation P = (1 – fc)20, where fc is the fraction of units contaminated. Thus, a 1:1000 rate of contamination would pass undetected in 98% of batches. Because of this statistical limitation, the validation of sterilization processes plays as important a role as passing the test.