Liposome toxicity in the mouse central nervous system.

This study has shown that while some liposomes are highly toxic to the central nervous system, others, of different composition, are tolerated well in the dosage used (0.02-0.05 ml = 4-12 mg of lipid/inoculum). Those composed of lecithin-cholesterol-dicetyl phosphate or lecithin-cholesterol-stearylamine produced generalised epileptic seizures and some deaths due to respiratory failure immediately after injection,and a subsequent widespread tissue necrosis. However liposomes composed of lecithin-cholesterol-phosphatidic acid, or dipalmitoyl lecithin only, produced minimal morphological changes and by the sixth day post-injection the pathology was limited to the mechanical trauma caused by the injection. It is concluded that liposomes of appropriate composition may be sufficiently benign to use as carriers of therapeutic agents into the CNS.