Methods are provided for making a dry powder blend pharmaceutical formulation comprising (i) forming microparticles which comprise a pharmaceutical agent; (ii) providing at least one excipient in the form of particles having a volume average diameter that is greater than the volume average diameter of the microparticles; (iii) blending the microparticles with the excipient to form a powder blend; and (iv) jet milling the powder blend to deagglomerate at least a portion of any of the microparticles which have agglomerated, while substantially maintaining the size and morphology of the individual microparticles. Jet milling advantageously can eliminate the need for more complicated wet deagglomeration processes, can lower residual moisture and solvent levels in the microparticles (which leads to better stability and handling properties for dry powder formulations), and can improve wettability, suspendability, and content uniformity of dry powder blend formulations.