a bioresorbable triblock copolymer according to formula 1 r - b - a - b - r wherein a is a hydrophilic polymer , b a hydrophobic polymer and r are end - groups , wherein r is h or a c1 - c30 organic moiety and wherein the copolymer is fluid in a temperature range of 0 ° c . to 37 ° c . a pharmaceutical composition including the triblock copolymer and at least one therapeutically active agent . the copolymer and pharmaceutical composition can be used for forming a depot in a human or animal body or as medical device .