Delivery system for biological material

A method for the preparation of microparticles from a liquid one-phase system containing biological material and a suitable amount of at least two compounds being incompatible in aqueous solution, the method consisting of the method step of evaporating water from the one-phase system leading to a phase separation with a dispersed phase and a continuous phase, thereby producing the formation of the microparticles, wherein the first compound of the at least two compounds is a dextran-based polymer, and the second compound of the at least two compounds is a polyaliphatic alcohol or derivative thereof, and wherein the evaporating step does not employ any emulsification means, vortexing step, or stirring step.