Biomedical Engineering Reference
In-Depth Information
Pall can easily be provided as a capsule filter, including low binding, high-
flow Fluorodyne
®
II polyvinylidene difluoride (PVDF) filters, Ultipor
®
N66
and positively-charged Posidyne
®
nylon 66 filters, Supor
®
polyethersulfone
filters, and Ultipor VF DV20 and DV50 virus removal filters. Kleenpak Nova
capsules are especially suited to pilot- and process-scale applications. They
can be autoclaved or sterilized by gamma irradiation and can be supplied
as part of presterilized processing systems such as a filter/tubing/bag set.
Additionally, the disposable Kleenpak sterile connector allows for the dry
connection of two separate fluid pathways, while maintaining the sterile
integrity of both. The connector consists of a male and a female connector,
each covered by a vented peel-away strip that protects the port and main-
tains the sterility of the sterile fluid pathway. Different connector options are
available to allow for the connection of 15.8 mm (5/8 in.), 13 mm (½ in.), 9.6
mm (3⁄8 in.), or 6 mm (¼ in.) nominal tubing. Kleenpak sterile connectors can
either be autoclaved up to 130°C or gamma-sterilized.
Viral clearance studies require viral spiking and many controls and vali-
dation protocols that might be difficult to conduct in-house. Several contract
laboratories are available to perform these studies, and generally the author
recommends outsourcing this phase of development:
AppTec Laboratory Services,
www.apptecls.com
Bioreliance, Inc.,
www.bioreliance.com
Charles River Laboratories,
www.criver.com/products/biopharm/
Inveresk Research Group, Inc.,
www.inveresk.com
Microbix Biosystems, Inc.,
www.microbix.com
Q-One Biotech, Ltd.,
www.q-one.com
Texcell - Institut Pasteur,
Buffers
Buffer preparation and storage requires large volume handling, generally
about 10 times the upstream media volume; some resins such as Protein A
require large buffer volumes. While there are several standard buffers, spe-
cific pH and electrolyte requirements make standardization of buffers diffi-
cult, and these are often process specific. While several development projects
underway promise to reduce the volume of buffer needed, the current sys-
tems are likely to stay the same for some time. The main efforts in this regard
include reducing the process steps.
