The present invention relates to a polymeric drug-device unit comprising a polyurethane block copolymer and an active agent. The polyurethane block copolymer is obtainable by reacting together a poly(alkylene oxide), a difunctional compound, a difunctional isocyanate and, optionally a block copolymer comprising poly(alkylene oxide) blocks. The polymeric drug-device unit generally takes the form of a vaginal ring.