A process for making particles for delivery of drug nanoparticles is disclosed herein. The process comprises the steps of (a) forming a suspension of drug nanoparticles by mixing a precipitant solution with an anti-solvent solution under micro-mixing environment, where the formed nanoparticles have a narrow particle size distribution; (b) providing an excipient to at least one of the precipitant solution, the anti-solvent solution and the suspension of drug nanoparticles, the excipient being selected to maintain said drug nanoparticles in a dispersed state when in liquid form; and (c) drying the suspension of drug nanoparticles containing the excipient therein to remove solvent therefrom, wherein removal of the solvent causes the excipient to solidify and thereby form micro-sized matrix particles, each micro-sized particle being comprised of drug nanoparticles dispersed in a solid matrix of the excipient.