Patent Number: 7,786,221

Title: Multi-armed, monofunctional, and hydrolytically stable derivatives of poly (ethylene glycol) and related polymers for modification of surfaces and molecules

Abstract: Multi-armed, monofunctional, and hydrolytically stable polymers are described having the structure ##STR00001## wherein Z is a moiety that can be activated for attachment to biologically active molecules such as proteins and wherein P and Q represent linkage fragments that join polymer arms poly.sub.a and poly.sub.b, respectively, to central carbon atom, C, by hydrolytically stable linkages in the absence of aromatic rings in the linkage fragments. R typically is hydrogen or methyl, but can be a linkage fragment that includes another polymer arm. A specific example is an mPEG disubstituted lysine having the structure ##STR00002## where mPEG.sub.a and mPEG.sub.b have the structure CH.sub.3O--(CH.sub.2CH.sub.2O).sub.nCH.sub.2CH.sub.2-- wherein n may be the same or different for poly.sub.a- and poly.sub.b- and can be from 1 to about 1,150 to provide molecular weights of from about 100 to 100,000.

Inventors: Harris; J. Milton (Huntsville, AL), Veronese; Francesco Maria (Padua, IT), Caliceti; Paola (Padua, IT), Schiavon; Oddone (Padua, IT)

Assignee: Nektar Therapeutics

International Classification: C08G 65/34 (20060101); C08F 283/00 (20060101); A61K 31/40 (20060101)

Expiration Date: 8/31/12018