ABSTRACT

Viruses were so named after the Latin for poison. Among the various descriptives used to

characterize viruses, “filterable” was a key attribute. Over the past three decades, there

have been phenomenal advances in membrane filtration technologies that have allowed

development of membranes that retain viruses by a mostly size-exclusion based

mechanism. Size-based (predominantly) filtration-removal of viruses is similar to

removal of other viable or non viable particulates (and several chapters in this book have

been dedicated to its discussion). The challenge lies in the fact that many therapeutic

proteins, either native or recombinant, are at the size limit of small viruses; consequently,

membrane filtration for virus removal must remove viruses of concern without

significantly compromising product yield.