chemical biological agents to be encapsulated are dissolved or dispersed in an aqueous paste of a gel - forming polyhydroxy polymer . subsequent addition of boric acid or a boric acid derivative at an alkaline ph converts the paste into a gel , 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 .