05149543 is referenced by 172 patents and cites 6 patents.

A method for encapsulating biologically-labile materials such as proteins, liposomes, bacteria and eucaryotic cells within a synthetic polymeric capsule, and the product thereof, are disclosed. The method is based on the use of a water-soluble polymer with charged side chains that are crosslinked with multivalent ions of the opposite charge to form a gel encapsulating biological material, that is optionally further stabilized by interactions with multivalent polyions of the same charge as those used to form the gel. In the preferred embodiment, hydrolytically stable polyphosphazenes are formed of monomers having carboxylic acid side groups that are crosslinked by divalent or trivalent cations such as Ca.sup.2+ or Al.sup.3+, then stabilized with a polycation such as poly-L-lysine. A variety of different compositions can be formed from the crosslinked polymer. In a preferred embodiment, microcapsules are made by spraying an aqueous solution of polyphosphazene and material to be encapsulated into a calcium chloride solution. A semipermeable membrane is formed on the microspheres by complexation of the surface carboxylate groups with poly(L-lysine).

Title
Ionically cross-linked polymeric microcapsules
Application Number
7/593684
Publication Number
5149543
Application Date
October 5, 1990
Publication Date
September 22, 1992
Inventor
Robert S Langer
Newton
MA, US
Harry R Allcock
State College
PA, US
Marie Chow
Brookline
MA, US
Karyn B Visscher
State College
PA, US
Carmen Bano
Valencia
ES
Smadar Cohen
Petach-Tickva
IL
Agent
Kilpatrick & Cody
Assignee
Pennsylvania Research Corporation
PA, US
Massachusetts Institute of Technology
MA, US
IPC
A61K 9/50
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