The present invention relates to pharmaceutical formulations suitable for targeting particular tissue and/or organ(s) with a formulated active ingredient, for example when administered upstream of the target organ or tissue, and to use of the same in treatment methods of preparing the formulations. The pharmaceutical formulations of the invention are for parenteral administration to a target tissue and comprise particles containing an active ingredient, and a biodegradable excipient, wherein 90% or more of the particles have a diameter of between 10 and 20 microns and the formulation is substantially free of particles with a diameter greater than 50 microns and less than 5 microns, such that where the formulation is administered upstream of the target tissue the ability of the active to pass through the target tissue and pass into systemic circulation is restricted.
