Cationic lipids as gene transfer agents:: a patent review

Background: Cationic lipids have been among the more efficient synthetic gene delivery reagents in vitro. They condense nucleic acids into cationic particles when the components are mixed together. Since the first studies were conducted, hundreds of cationic lipids have been synthesized as candidates for non-viral gene delivery and a few entered clinical trials. Objective: This paper reviews the lipid structure of cationic lipids, their structure-activity relationship, toxicity and transfection efficacy. A revision of the more recent patents is also included. Methods: Bibliographic research was carried out using the PubMed database. Patent literature was searched using the Derwent Innovations Index(SM). Results/conclusions: There is a wide range of scientific literature and patents about new cationic lipids and at present many research groups focus their investigation on the development of new molecules. Advances in the development of new technologies to better understand the in vitro and in vivo behavior of the lipoplexes will help to redesign new cationic lipids. The results obtained in clinical trials confirm gene therapy as a very promising therapeutic tool in the future.