Drug – bio-affecting and body treating compositions – Radionuclide or intended radionuclide containing; adjuvant... – Attached to cyclopentano-hydrophenanthrene ; derivative thereof
Reexamination Certificate
2000-09-14
2004-02-24
Nguyen, Dave T. (Department: 1635)
Drug, bio-affecting and body treating compositions
Radionuclide or intended radionuclide containing; adjuvant...
Attached to cyclopentano-hydrophenanthrene ; derivative thereof
C530S402000, C424S450000, C525S007000, C554S035000, C564S123000, C564S270000
Reexamination Certificate
active
06696038
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to delivery of a bioactive agent. More particularly, the invention relates to a composition and method for delivering bioactive agents, such as DNA, RNA, oligonucleotides, proteins, peptides, and drugs, by facilitating their transmembrane transport or by enhancing their adhesion to biological surfaces. It relates particularly to a novel cationic lipopolymer comprising a branched polyethylenimine (PEI), a cholesterol derived lipid anchor, and a biodegradable linker which covalently links the branched PEI and cholesterol derived lipid anchor. One example of such a novel lipolymer is poly {(ethylene imine)-co-[N-2-aminoethyl)ethylene imine]-co-[N-(N-cholesteryloxycabonyl-(2-aminoethyl))ethylene imine]} (hereafter referred to as “PEACE”). The cationic lipopolymers of the present invention can be used in drug delivery and are especially useful for delivery of a nucleic acid or any anionic bioactive agent.
BACKGROUND OF THE INVENTION
Gene therapy is generally considered as a promising approach not only for the treatment of diseases with genetic defects but also in the development of strategies for treatment and prevention of chronic diseases such as cancer, cardiovascular disease and rheumatoid arthritis. However, nucleic acids as well as other polyanionic substances are rapidly degraded by nucleases and exhibit poor cellular uptake when delivered in aqueous solutions. Since early efforts to identify methods for delivery of nucleic acids in tissue culture cells in the mid 1950's, steady progress has been made towards improving delivery of functional DNA, RNA, and antisense oligonucleotides in vitro and in vivo.
The gene carriers used so far include viral systems (retroviruses, adenoviruses, adeno-associated viruses, or herpes simplex viruses) or nonviral systems (liposomes, polymers, peptides, calcium phosphate precipitation and electroporation). Viral vectors have been shown to have high transfection efficiency when compared to non-viral vectors, but due to several drawbacks, such as targeting only dividing cells, random DNA insertion, their low capacity for carrying large sized therapeutic genes, risk of replication, and possible host immune reaction, their use in vivo is severely limited.
Compared to viral vectors, nonviral vectors are easy to make and less likely to produce immune reactions, and there is no replication reaction required. There has been increasing attention focused on the development of safe and efficient nonviral gene transfer vectors, which are either polycationic polymers or cationic lipids. Polycationic polymers such as poly-L-lysine, poly-L-omithine and polyethyleneimine (PEI), that interact with DNA to form polyionic complexes, have been introduced for use in gene delivery. Various cationic lipids have also been shown to form lipoplexes with DNA and induce efficient transfection of various eukaryotic cells. Among such kinds of synthetic vectors, cationic lipids are widely used because it is possible to design and synthesize numerous derivatives that are outstanding in the aspects of transfection efficiency, biodegradability and low toxicity. Many different cationic lipids are commercially available and several lipids have already been used in the clinical setting. Among them, cationic cholesterol derivatives are known to be very useful because of their high transfection efficiency in vitro. Although the mechanism of this transfection activity is not yet clear, it probably involves binding of the DNA/lipid complex with the cell surface via excess positive charges on the complex. Cell surface bound complexes are probably internalized and the DNA released into the cytoplasm of the cell from an endocytic compartment.
However, it is not feasible to directly extend in vitro transfection technology to in vivo applications. Relative to in vivo use, the biggest drawback of the diether lipids, such as N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethyl ammonium chloride (DOTMA) or Lipofectin is that they are not natural metabolites of the body, and are thus not biodegradable and they are toxic to cells. In addition, it has been reported that cationic lipid transfection is inhibited by factors present in serum and thus it is an ineffective means for the introduction of genetic material into cells in vivo.
An ideal transfection reagent should exhibit a high level of transfection activity without needing any mechanical or physical manipulation of the cells or tissues. The reagent should be non-toxic, or minimally toxic, at the effective dose. In order to avoid any long-term adverse side-effects on the treated cells, it should also be biodegradable. When gene carriers are used for delivery of nucleic acids in vivo, it is essential that the gene carriers themselves be nontoxic and that they degrade into non-toxic products. To minimize the toxicity of the intact gene carrier and its degradation products, the design of gene carriers needs to be based on naturally occurring metabolites. U.S. Pat. No. 5,283,185, to Epand et al. (hereafter the '185 patent), discloses a method for facilitating the transfer of nucleic acids into cells comprising preparing a mixed lipid dispersion of a cationic lipid. 3&bgr;[N-(N′,N″-dimethylaminoethane)-carbamoyl]cholesterol(DC-cholesterol) with a co-lipid in a suitable carrier solvent. The method disclosed in the '185 patent involves using a halogenated solvent in preparing a liposome suspension. For pharmaceutical applications, residues of halogenated solvents cannot be practically removed from a preparation after having been introduced. U.S. Pat. No. 5,753,262, (hereafter the '262 patent) discloses using the acid salt of the lipid 3&bgr;[N-(N′,N″-dimethylaminoethane)-carbamoyl]cholesterol (DC-cholesterol) and a helper lipid such as dioleoyl phosphatidylethanolamine (DOPE) or dioleoylphosphatidylcholine (DOPC) to produce effective transfection in vitro. In addition, these cationic lipids have been proven less efficient in gene transfer in vivo.
Because of their sub-cellular size, nanoparticles are hypothesized to enhance interfacial cellular uptake, thus achieving in a true sense a “local pharmacological drug effect.” It is also hypothesized that there would be enhanced cellular uptake of drugs contained in nanoparticles (due to endocytosis) compared to the corresponding free drugs. Nanoparticles have been investigated as drug carrier systems for tumor localization of therapeutic agents in cancer therapy, for intracellular targeting (antiviral or antibacterial agents), for targeting to the reticuloendothelial system (parasitic infections), as an immunological adjuvant (by oral and subcutaneous routes), for ocular delivery with sustained drug action, and for prolonged systemic drug therapy.
In view of the foregoing, it will be appreciated that providing a gene carrier that is non-toxic, biodegradable, and capable of forming nanoparticles, liposomes, or micelles for gene therapy and drug delivery, is desired. The novel gene carrier of the present invention comprises a novel cationic lipopolymer comprising a branched polyethylenimine(PEI), a cholesterol derived lipid anchor, and a biodegradable linker which covalently links the branched PEI and cholesterol derived lipid anchor. The lipolymer of the present invention is useful for preparing a cationic liposome, or a cationic micelle for drug delivery, especially for delivery of nucleic acids, other anionic bioactive molecules or both and is readily susceptible to metabolic degradation after incorporation into the cell.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a biodegradable cationic lipopolymer, having reduced in vivo and in vitro toxicity, for delivery of drugs or other bioactive agents to an individual in need thereof.
The present invention also provides a cationic lipopolymer for delivery of nucleic acids which carries out both stable and transient transfection of polynucleotides such as DNA and RNA into cells more effectively.
The
Furgeson Darin Y.
Han Sang-Oh
Mahato Ram I.
Expression Genetics, Inc.
Nguyen Dave T.
Schnizer Richard
Thorpe North & Western LLP
LandOfFree
Cationic lipopolymer as biocompatible gene delivery agent does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cationic lipopolymer as biocompatible gene delivery agent, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cationic lipopolymer as biocompatible gene delivery agent will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3296858