A method for preparing a microparticle suspension, which comprises: (a) providing protein microparticles having a median diameter between 5 and 13 microns and a GSD less than 2.5; (b) combining the microparticles with a liquid, pharmaceutically acceptable, water miscible media to create a first mixture; (c) adding an aqueous media to the first mixture to create second mixture; and (d) mixing the second mixture to create a microparticle suspension is described. The suspension are injectable even when they contain a relatively high concentration of protein.