Amphoteric liposomes comprising imino lipids

Abstract

The invention concerns lipid assemblies, liposomes having an outer surface comprising a mixture of anionic and cationic moieties; wherein at least a portion of the cationic moieties are imino moieties that are essentially charged under physiological conditions, and their use for serum resistant transfection of cells.

What is claimed is: 
     
         1 . Lipid assemblies comprising anionic and cationic amphiphiles; wherein at least a portion of the cationic amphiphiles are imino lipids that are substantially charged under physiological conditions, and wherein the anionic amphiphiles are carboxyl or phosphate lipids and wherein further the charge ratio between the cationic and anionic amphiphiles is 1.5 or less. 
     
     
         2 . Lipid assemblies as in  claim 1  comprising anionic and cationic amphiphiles; wherein at least a portion of the cationic amphiphiles are imino lipids that are substantially charged under physiological conditions, and wherein further at least a portion of the anionic amphiphiles are carboxyl lipids, and wherein the ratio between the cationic and anionic amphiphiles is lower or equal to 1.5. 
     
     
         3 . Lipid assemblies as in  claim 1  or  2  comprising a combination of lipids wherein the cationic lipids of said combination comprise a guanido moiety and the anionic lipids of said combination comprise a carboxyl group, further characterized in that the ratio between the guanido moieties and the carboxyl groups is lower or equal to 1.5. 
     
     
         4 . Lipid assemblies as in  claim 1  comprising anionic and cationic amphiphilies wherein at least a portion of the cationic amphiphiles are imino lipids that are substantially charged under physiological conditions, and wherein further at least a portion of the anionic amphiphiles are phosphate lipids, and wherein the charge ratio between the cationic and anionic amphiphiles is lower or equal to 1.5. 
     
     
         5 . Lipid assemblies as in any of the  claims 1  to  4 , further characterized in that the charged imino groups of the cationic amphiphiles have a pK of greater than 7.5 and are selected from imines, amidines, pyridines, 2-aminopyridines, heterocyclic nitrogen bases, guanido moieties, isoureas or thioisoureas. 
     
     
         6 . Lipid assemblies as in any of the  claims 1  to  5 , wherein in cationic amphiphiles are selected from the group comprising structures of I1 to I113, structures A1 to A21 or structures L1 to L17, wherein members od said group are further selected according to a pK greater 7.5. 
     
     
         7 . Lipid assemblies as in any of the preceding claims, further characterized in that the cationic lipids are selected from the group of PONA, CHOLGUA, GUADACA, MPDACA or SAINT-18. 
     
     
         8 . Lipid assemblies as in any of the preceding claims, further characterized in that the anionic lipids are selected from the group of CHEMS, DMGS, DOGS, DOPA or POPA. 
     
     
         9 . Lipid assemblies as any of the preceding claims, further characterized in that said assemblies have a charge ratio of the cationic and anionic lipids of between 0.5 and 1.5. 
     
     
         10 . Lipid assemblies as in any of the  claims 1  to  9 , further characterized in that said assemblies are liposomes. 
     
     
         11 . Liposomes as in  claim 10 , further comprising a neutral or zwitterionic lipid selected from cholesterol, phosphatidylcholine, phosphatidylethanolamine, sphingomyeline or mixtures thereof. 
     
     
         12 . Liposomes as in  claim 11 , further characterized in that the neutral lipid is cholesterol and the molar fraction of cholesterol in the lipid mixture is between 10 and 50 mol %. 
     
     
         13 . Liposomes as in  claim 10 ,  11  or  12 , further comprising PEG lipids. 
     
     
         14 . Liposomes as in  claim 13 , further characterized in that the PEG lipids are situated in the outermost membrane leaflet. 
     
     
         15 . Liposomes as in any of the preceding  claims 10  to  14 , further comprising an active pharmaceutical ingredient. 
     
     
         16 . Liposomes as in  claim 15 , wherein said pharmaceutical ingredient is an oligonucleotide. 
     
     
         17 . Liposomes as in  claim 16 , wherein said oligonucleotide is a decoy oligonucleotide, and antisense oligonucleotide, a siRNA, an agent influencing transcription, a ribozyme, DNAzyme or an aptamer. 
     
     
         18 . Liposomes as in  claim 17 , wherein said oligonucleotides comprise modified nucleosides such as DNA, RNA, LNA, PNA, 2′OMe RNA, 2′ MOE RNA, 2′F RNA in their phosphodiester or phosphothioate forms. 
     
     
         19 . The liposomes of  claim 14 , produced by a process comprising the steps of (i) formation and sealing of the liposomes in the presence of an active ingredient and (ii) a separate addition of PEG-lipids after said step (i). 
     
     
         20 . Use of the liposomes as claimed in any of  claims 10  to  19  for the in vivo, in vitro or ex vivo transfection of cells. 
     
     
         21 . Use of an aerosol comprising liposomes as claimed in any of the  claims 10  to  19  for the transfection of lung cells.