RT Journal Article SR Electronic T1 Loading and Unloading of Freeze-Dryers: Airborne Contamination Risks for Aseptically Manufactured Sterile Drug Products JF PDA Journal of Pharmaceutical Science and Technology JO PDA J Pharm Sci Technol FD Parenteral Drug Association (PDA) SP 44 OP 50 VO 61 IS 1 A1 Bengt Ljungqvist A1 Berit Reinmüller YR 2007 UL http://journal.pda.org/content/61/1/44.abstract AB In pharmaceutical manufacturing, freeze-drying processes can be adversely affected by temperature differences relative to the surrounding air. Loading and unloading of freeze-dryers are performed either without or with temperature differences between the cleanroom and the chamber of the freeze-dryer. This operation can cause a flow of room air through the opening, creating a contamination risk, especially when manual handling of material is performed in this area. To minimize this risk, a high-efficiency particulate air (HEPA) filter unit should be installed above the opening to provide clean air and protect the opening. Here the theoretical relationships are discussed and design criteria are presented.