disclosed is a polymer of the formula i : wherein : z is — o — or — nh —; r 1 represents a non - functional backbone of a hydroxy acid or amino acid derived from a cyclic ester or diester or cyclic amide or diamide monomer ; r 2 represents a non - functional chain derived from an epoxide monomer , said chain ending with a graftable hydroxy or carboxylic group ; n is the number of units derived from the monomers ; m is the number of units derived from the monomers ; and x is equal to n + m , the ratio m / x ranging from 0 . 005 to 0 . 30 . also disclosed is a process of preparing this functionalizable polymer to the hydroxy or carboxylic groups of which can be grafted a compound selected from the group consisting of : ligands specific to cellular receptors , such as selectine e ; lipids ; peptides ; polyethers ; polyacrylates ; natural polymers ; polyosides ; antigens or antibodies ; salen ; and cyclodextrins . the so grafted polymer can be used as carried or excipient in the biomedical and pharmaceutical fields .