Abstract: A method and apparatus for multicomponent surface modified aerosol particle production suitable for, for instance, therapeutic, cosmetic or diagnostic use in which an aerosol containing an active agent is introduced in an aerosol reactor together with a surface agent or surface agent source and/or precursor and wherein the surface agent and/or surface agent precursor is volatilizable. The surface agent vapor saturation ratio is elevated so to cause it to nucleate from the gas phase. Reactor conditions are maintaining such that the active agent remains in the condensed phase and provides a surface for the surface agent to deposit on the active agent containing aerosol particle thus producing surface modified aerosol particles. The method can be used for batch or continuous production. Particles made according to the method and powders and dispersions containing the particles are also described.