Stable and monodisperse lipoplex formulations for gene delivery

Abstract

A stable single vial lipoplex formulation has been of a T-connector. Homogenous cationic liposome prepdeveloped that can be stored frozen without losing either arations were prepared by extrusion in two different size biological activity or physical stability. This formulation was ranges of either 400 or 100 nm. Extruded liposomes proidentified by systematically controlling several formulation duced more monodisperse and physically stable lipoplex variables and without introducing either stabilizers or surformulations than unextruded liposomes, but the formufactants. Analytical assays were used to unambiguously lations prepared with 100 nm liposomes were less active characterize the formulations. The critical formulation parain in vitro transfection assays than either the 400 nm or meters were: (1) the size of the cationic liposomes; (2) the unextruded liposomes. Low ionic strength and 5% sorbitol rate and method of DNA and cationic liposome mixing; and were required for the lipoplex formulations to survive freez-(3) the ionic strength of the suspending vehicle. The mixing ing and thawing. A frozen lipoplex formulation stored for conditions were precisely controlled by using a novel, spemore than a year maintained its biological activity. These cially designed continuous flow pumping system in which results have broad implications for the pharmaceutical the DNA and liposome solutions were mixed at the junction development of lipoplex formulations for gene delivery.

Studies of direct intratumoral gene transfer using cationic lipid-complexed plasmid DNA

“…gene transfer. Optimized L:D complexes may produce particles that (a) are more resistant to nuclease digestion, 32 (b) contain highly potent L:D complex conformations, 17 or (c) are more efficiently retained within the tumor (see below).…”

“…Therefore, novel cationic lipid reagents, employing unique chemistries, are being developed; in addition, research is underway to understand the structure-function relationships of this emerging technology. 16,17 The in vitro transfection activity of a particular cationic lipid seldom predicts its in vivo activity, 6,18 and there are few standards regarding the most efficient means of using lipid complexes for i.t. transfection.…”

Transferrin-Associated Lipoplexes as Gene Delivery Systems: Relevance of Mode of Preparation and Biophysical Properties

“…The increased capacity of HBS-Tf-complexes to associate with the cells, in terms of both lipid and DNA, compared to Dex-Tf-complexes may partially justify that finding. Favorable interactions and binding to the cell surface as well as efficient protection of DNA against nucleases collectively concur with the increased transfection capacity exhibited by the HBS-Tfcomplexes (Konopka et al, 1996;Tomlinson & Rolland, 1996;Zelphati et al, 1998). It has been clearly demonstrated that endocytosis constitutes the main route of cell entry of lipoplexes (Hui et al, 1996;Yu et al, 2004;Zabner et al, 1995;Zuhorn et al, 2002).…”

A method for concentrating lipid peptide DNA and siRNA nanocomplexes that retains their structure and transfection efficiency

“…At dextran concentrations of 150 g/L nanoparticle concentrations of 0.59-4.6 mg/mL were achieved, which is in the target range for possible clinical applications. 10,29 The effect of the starting volume at three different concentrations of dextran (100 g/L, 200 g/L, and 300 g/L) was investigated for its effects on the rate of concentration increase. Table 1 shows that smaller starting volumes were concentrated more quickly.…”