The invention provides a composition for use as a delivery vehicle comprising at least one thermo-responsive polymer (polymer A) and at least one ion-sensitive polymer (polymer B) in a liquid formulation. Polymer A is preferably a polyoxyethylene-polyoxypropylene block copolymer or a cellulose derivative. Polymer B a polysaccharide. The composition can include an active substance for delivery or can be used as a delivery vehicle for a substance added at the time of administration such as mesenchymal stem cells.