Spray dry method for encapsulation of biological moieties and chemicals in polymers cross-linked by multivalent ions for controlled release applications

Abstract

Microencapsulation of bioactive and chemical cargo in a stable, cross-linked polymer matrix is presented that results in small particle sizes and is easily scaled-up for industrial applications. A formulation of a salt of an acid soluble multivalent ion, an acid neutralized with a volatile base and one or more monomers that cross-link in the presence of multivalent ions is atomized into droplets. Cross-linking is achieved upon atomization where the volatile base is vaporized resulting in a reduction of the pH of the formulation and the temporal release of multivalent ions from the salt that cross-link the monomers forming a capsule. The incorporation of additional polymers or hydrophobic compounds in the formulation allows control of hydration properties of the particles to control the release of the encapsulated compounds. The operational parameters can also be controlled to affect capsule properties such as particle-size and particle-size distribution.