Brain delivery of proteins by the intranasal route of administration: A comparison of cationic liposomes versus aqueous solution formulations

The goal of this research was to evaluate the effectiveness of cationic liposomes for intranasal administration of proteins to the brain. Cationic liposomes were loaded with a model protein, ovalbumin (OVAL), and a 50 µg dose was administered intranasally to rats. In qualitative studies, liposomes were loaded with Alexa 488‐OVAL and delivery was assessed by fluorescence microscopy. By 6 and 24 h after administration, Alexa 488‐OVAL deposits were widely distributed throughout brain, with apparent cellular uptake in midbrain by 6 h after administration. In quantitative studies, liposomes were loaded with 111In‐OVAL, and distribution to brain and peripheral tissues was monitored by gamma counting at 1, 4, 6, and 24 h after administration. The highest brain concentrations were achieved at the shortest time point, 1 h, for both liposomal and aqueous OVAL. However, the liposomes yielded higher 111In‐OVAL concentrations in brain than 111In‐OVAL in PBS. Moreover, a 2 µg/µL form of liposomal OVAL yielded a higher percentage of dose in brain, and a lower percentage in stomach and intestines, than twice the volume of a 1 µg/µL preparation. Cationic liposomes may provide a novel, noninvasive strategy for delivery of neuroactive proteins to the brain for treatment of central nervous system disorders. © 2009 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1745–1761, 2010