Convection-enhanced delivery (CED) is used as a method to deliver a direct infusion of therapeutic agents to the central nervous center thus circumventing the blood-blood barrier. A non-PEGylated liposomal composition comprising at least one saturated neutral phospholipid and at least one saturated anionic phospholipid and a therapeutic or diagnostic agent encapsulated therein is used to overcome toxicity associated with high peak drug concentration delivered locally CED as well as to increase tissue distribution volume for an improved sustained drug release. In one embodiment, the liposome composition comprises a molar ratio of DSPC:DSPG:CHOL of 7:2:1 and the therapeutic or diagnostic agent is selected from topotecan, conotoxin, gadodiamide or rhodamine, and is used in the treatment of epilepsy.
