New cationic polymers are provided that are suitable for the preparation of microspheres. The microspheres are capable of loading and eluting anionic species such as drugs and find use in i.a. embolotherapy本發明提供適合於製備微球體之新穎陽離子聚合物。該等微球體能夠負載且洗提諸如藥物之陰離子物質且可用於動脈內栓塞療法中。