Provided is an apparatus for producing solid polymeric microparticles, the apparatus comprising a plurality of liquid droplet generators for forming liquid droplets of a first liquid, and a nozzle for forming a jet of a second liquid, wherein the plurality of liquid droplet generators and the nozzle are arranged relative to each other such that, in use, liquid droplets from the plurality of liquid droplet generators pass through a gas into said jet of second liquid. Also provided is a process for producing solid microparticles, the process comprising: providing a first liquid comprising a solute and a solvent, the solute comprising a biocompatible polymer, the concentration of polymer in the first liquid being at least 10% w/v, ‘w’ being the weight of the polymer and ‘v’ being the volume of the solvent, providing a plurality of liquid droplet generators operable to generate liquid droplets, providing a jet of a second liquid, causing the plurality of liquid droplet generators to form liquid droplets of the first liquid, passing the liquid droplets through a gas to contact the jet of the second liquid so as to cause the solvent to exit the droplets, thus forming solid microparticles, the solubility of the solvent in the second liquid being at least 5 g of solvent per 100 ml of second liquid, the solvent being substantially miscible with the second liquid.