A drug-polymer conjugate, which is a copolymer of at least one monomer of formula (I): (I) where: X may be the same or different at each occurrence and represents a terminal functional group comprising an alkyne or an azide; Q is independently selected at each occurrence and may be present or absent and when present, represents a linking group; R is selected from the group consisting of linear or branched hydrocarbon, optionally substituted aryl and optionally substituted heteroaryl; D is a releasable drug selected from prostaglandins, β-blockers and mixtures thereof; L is a linker group group; and at least one co-monomer of Formula III III J represents a linking functional group, n is 2 to 8, preferably 3 to 8; Y comprises a polyether of formula (ORa)m wherein Ra is independently ethylene, propylene and butylene and m is from 1 to 300 (preferably 2 to 300) and the polyether is in chain with one or more groups which are preferably selected from one or more of optionally substituted straight or branched Ci to do alkylene, amino, ether, ester, amide, carbonate and carbamate; A may be the same or different at each occurrence and represents a group comprising a terminal functional group comprising an alkyne or an azide functionality, wherein said terminal functional group is complementary to the terminal functional group X of formula (I) providing triazole moieties from reaction of X and A.