NEWSLETTER
ISSUE
Apr to Jun, 2019 Volume 8
Contamination control in Sterilizer area of Sterile manufacturing facility
Double door sterilizer used in Pharmaceuticals, Hospitals, Research Institute and other industrial facilities consist of Sterile (Non-Contained) and Non-Sterile (Contained) work areas. Purpose of the equipment is to sterilize the material that passes from Non-sterile to sterile area. As the equipment is installed right into the wall opening that separates these work areas, it is considered as the most critical point for control of bioburden or contamination.
In order to control the bioburden stringently, it is necessary to separate these work areas. A positive air pressure in sterile area is maintained to avoid the contamination. However, there are two possible routes for microorganisms to contaminate the sterile area, 1) Directly through sterilizer chamber and 2) Outside the sterilizer (Gap between the sterilizer and partition wall). For sterilizer chamber, the door interlock device is employed whereas for gap between sterilizer and wall, Biological sealing flange or Bio-Seal is used.
Door interlock device is used to intercept the route of contamination. It prevents transmission of airborne microorganisms or particulate matters from one work area to another through chamber. Both the doors, on sterile and non-sterile side, do not open simultaneously so the air circulation between contaminated area (non-sterile) and clean area (sterile) is avoided. Principally, the sterile side door will remain locked during loading of sterilizer & throughout the sterilizer cycle, whereas, non-sterile door will remain locked during unloading of sterilized material in sterile area.
A Bio-seal provides separation and positive sealing between the Sterile and non-sterile side. It is installed at the non-operating end (Sterile side) of a sterilizer. The Bio-seal is comprised of a stainless-steel plate (formed in box structure) that is connected/assembled to sterilizer chamber at one end and to the partition wall at the other end. Assembly at both the ends are sealed to provide leak-free joint and prevent contamination. Bio-seal assembly at the sterilizer end is sealed with silicon gasket whereas on partition wall end its sealed with silicon caulking.
Testing of Bio-seal assembly is necessary to ensure the integrity of the seal and prevent the contamination in sterile area. Testing should be performed by trained and experienced personnel who are familiar with the testing standards. The testing of Bio-seal is carried out using the industry standard bulk smoke leak test. Smoke generated for this test has a particulate size not more than 0.2 microns. During the test period, room should be maintained at a negative pressure with differential of at least 13.7 Pascal. The seal is considered secure if no visible penetration of smoke through Bio-seal is observed.
