Targeted Cationic Liposomes , Technologies , and Developments

Anas El-Aneed is a doctoral student in biochemistry at the School of Pharmacy at Memorial University of Newfoundland, 300 Prince Philip Dr., St. John’s, NL, A1B 3V6 Canada, tel. 709.737.4331, fax 709.777.7044, [email protected]. ationic liposomes are widely used to transfer genetic materials into specific cells. A good liposomal formulation for gene therapy should encapsulate and protect the nucleic acid materials, escape endosomal degradation, and reach the tumor site. The last goal can be achieved by incorporating a tumor-specific ligand that can deliver DNA to the targeted tissue. The same strategies that are applied when using anionic liposomes to develop tissue-specific formulations also can be applied when using targeted cationic liposomes. Because cationic and noncationic liposomes have similar composition and structure, ligand attachment strategies also are similar, and any discussion in this area cannot separate the two liposomal groups. The two main strategies in developing targeted liposomes are the attachment of a monoclonal antibody (mAb) (i.e., immunoliposomes) or the attachment of a tissue-specific ligand to the surface of the liposomes. This article briefly reviews livertargeted and tumor-specific liposomes as examples of targeted liposomes. This article also describes liposome–ligand attachment techniques.