Sterility Assurance and Models for Assessing Airborne Bacterial Contamination

Abstract

Product contamination in aseptic pharmaceutical manufacturing areas can occur by several routes and from several sources but the major route of contamination that cannot be effectively controlled is the airborne one. Process simulation by filling containers with bacteriological medium is an effective method of assessing the expected bacteriological quality of the product. However, these filling tests must be limited in number and are not sufficiently sensitive to show levels much below I contaminant in 1000. An explanation of the mechanisms of airborne contamination in clean rooms are given in this paper and a model is derived which can give a reasonable prediction of the amount of product contamination from a knowledge of the concentration of the airborne bacteria as well as a number of other variables associated with the filling process. This method may be used to control the process between medium fills as well as optimizing existing and future filling processes. To adopt this method confidence must be placed in the methods used to determine airborne bacteria. Current methods used in the pharmaceutical industry are often of insufficient accuracy and suggestions are given to increase their accuracy.