The invention provides a multi-arm block copolymer for use in delivering a
variety of bioactive agents. The copolymer of the invention contains a
central core from which extend multiple (3 or more) copolymer arms. Each
copolymer arm possesses an inner polypeptide segment and an outer
hydrophilic polymer segment. Thus, the overall structure of the copolymer
comprises an inner core region that includes the central core and the
inner polypeptide segment, while the outer core region is hydrophilic in
nature. The multi-arm copolymer of the invention is particularly useful
for delivery of biologically active agents that can be entrapped within
the inner core region.