Myths concerning the use of cationic liposomes in vivo

Varied results have been obtained using cationic liposomes for in vivo delivery. Furthermore, optimisation of cationic liposomal complexes for in vivo applications is complicated, involving many diverse components. These components include nucleic acid purification, plasmid design, formulation of the delivery vehicle, administration route and schedule, dosing, detection of gene expression and others. Broad assumptions have frequently been made based on data obtained from focused studies using cationic liposomes. However, these assumptions do not necessarily apply to all delivery vehicles and, most likely, do not apply to many liposomal systems, when considering these other key components which influence the results obtained in vivo. Optimising all the components of the delivery system is pivotal and will allow broad use of liposomal complexes to treat or cure human diseases or disorders. This review will highlight the features of liposomes that contribute to successful delivery, gene expression and efficacy.