Abstract: A method for the preparation of microparticles, and the product thereof, that includes dispersing a substantially water insoluble non-ionic or ionic polymer in an aqueous solution in which the substance to be delivered is also dissolved, dispersed or suspended, and then coagulating the polymer together with the substance by impact forces to form a microparticle. In an alternative embodiment, the microparticle is formed by coagulation of an aqueous polymeric dispersion through the use of electrolytes, pH changes, organic solvents in low concentrations (the minimal amount necessary to break up the dispersion), or temperature changes to form polymer matrices encapsulating biological materials.