**3. Polymeric drug delivery**

#### **3.1. History**

In order to overcome the drawbacks mentioned above and to achieve the local controlled release of chemotherapeutics, efforts have been made to develop delivery system with synthetic polymers. Early in 1970s, an ethylene vinylacetate copolymer (EVAc) was em‐ ployed to generate a poriferous matrix and incorporate macromolecules such as chemothera‐ peutics (14). The impregnated agents are released from the matrix in a predictable and sustained style by diffusion. The rate of release depends on the physicochemical property of the agents, such as solubility, charge, and molecular weight. However, EVAc was restricted by the non‐degradable nature and was therefore seldom used in neuro‐oncology.
