the invention relates to a microencapsulated emulsion a drug - dispersed oil core surrounded by a water - insoluble capsule material . the capsule material is made up of a polysaccharide which has metal chelating capacity , a biocompatible and water - soluble polymer for improving the physical properties of the capsule material , and emulsifying agents . the ratio of polysaccharide to polymer in the capsule material is at least capsule material , and emulsifying agents . the ratio of polysaccharide to polymer in the capsule material is at least 0 . 25 .