A pharmaceutically-active polymeric compound of the general formula (I), Y -[Yn - LINK B - X]m - LINK B (I) wherein (i) X is a coupled biological coupling agent of the general formula (II) Bio - LINK A - Bio (II) wherein Bio is a biologically active agent fragment or precursor thereof linked to LINK A through a hydrolysable covalent bond and LINK A is a coupled central flexible linear first segment of <2000 theoretical molecular weight linked to each of said Bio fragments (ii) Y is LINK B-OLIGO wherein (a) LINK B is a coupled second segment linking one OLIGO to another OLIGO and an OLIGO to X or precursor thereof and (b) OLIGO is a short length of polymer segment having a molecular weight of less than 5,000 and comprising less than 100 monomeric repeating units (iii) m is 1- 40 and (iv) n is selected from 2 - 50. The compounds are useful as biomaterials, particularly, providing antibacterial activity. In vivo. Also provided are biological coupling agents useful as intermediates in the preparation of the pharmaceutically-active polymeric compounds.
