The present invention is directed to an improvement in a delivery system, the system comprising a wall that surrounds an internal lumen or compartment which contains a thermo-responsive beneficial agent formulation, an expandable driving member and an optional density member, and having an exit opening, and wherein the improvement comprises a) a viscosity-inducing amount of an inert viscosity-inducing agent in the thermo-responsive beneficial agent composition for increasing the viscosity of the beneficial agent composition, and/or b) a pressure-inducing exit member in the exit opening in the wall for increasing the pressure inside the lumen.