chemical biological agents to be encapsulated are dissolved or dispersed in an aqueous solution of polyhydroxy polymer xanthate . simultaneous addition of a strong acid and a coupling agent to the solution insolubilizes the polyhydroxy polymer without degrading the xanthate moiety , thereby entrapping the agents in a protective matrix . encapsulation of biologically active compositions provides a shield against hostile environments , improves safety in handling , and slows the release of such compounds to the surrounding medium . highly volatile liquids are protected against losses by evaporation . encapsulation also provides protection against decomposition from exposure to ultraviolet light .