Double emulsion system is a kind of multi emulsion system, it has the ability to protect substances and release them in a controlled manner from inside one phase to another. Recently, it achieves rapid advances in drug delivery (such as cancer drugs, hormones, etc.), food and other fields by combining double emulsion system with the traditional preparation methods of microcapsules, and it can not effectively encapsulate highly water soluble substances by the traditional microcapsule preparation methods was solved. Based on this, some extended n...