A method of producing a dried formulation for an active substance such as a drug compound is described. The method involves dispersing a discontinuous phase (e.g. an oil-based or lipidic medium) comprising the active substance into a continuous phase (e.g. water) so as to form a two-phase liquid system comprising droplets of said discontinuous phase, allowing nanoparticles to congregate at the phase interface at the surface of the droplets such that at least one layer of nanoparticles coat the droplets and thereby provide sufficient structural integrity to the droplets to enable the subsequent removal of the continuous phase, and thereafter removing the continuous phase from the nanoparticle-coated droplets to produce a dried formulation.