RT Journal Article SR Electronic T1 Particulate Contamination from Siliconized Rubber Closures for Freeze Drying JF PDA Journal of Pharmaceutical Science and Technology JO PDA J Pharm Sci Technol FD Parenteral Drug Association (PDA) SP 24 OP 29 VO 50 IS 1 A1 U. Gebhardt A1 N. A. Grumbridge A1 A. Knoch YR 1996 UL http://journal.pda.org/content/50/1/24.abstract AB It can be shown that siliconized closures for freeze drying may cause the opalescence and turbidity observed in freeze-dried products after reconstitution. Closures of different rubber composition show different intensities of turbidity when treated identically with the same quantity and type of silicone oil. Clear solutions are obtained after reconstitution if ETFE-coated closures are used instead of siliconized closures. Samples stored at 4°C for up to 6 months show no change in the intensity of turbidity, while the turbidity of samples manufactured with siliconized closures and stored at higher temperatures increase with time. Samples with ETFE-coated closures show clear solutions when stored at 25°C and 37°C for up to 6 months and at 45°C for 3 months. After 6 months only a very weak opalescence could be observed in these samples.