The present embodiments provide systems and methods suitable for delivering a therapeutic agent to a target site. A container holds the therapeutic agent and a pressure source has pressurized fluid in selective fluid communication with at least a portion of the container. A catheter, in fluid communication with the container, has a lumen sized for delivery of the therapeutic agent to a target site. In one embodiment, a diameter of particles of the therapeutic agent is in a range of between about 1 micron to about 925 microns, a mass of the particles of the therapeutic agent is in a range of between about 0.0001 mg to about 0.5 mg, a ratio of an inner diameter of the catheter to the diameter of particles is at least 4:1, and a regulated pressure of the pressurized fluid is between about 0.01 psi to about 100 psi.