Liposomal apparatus and manufacturing methods

Abstract

The present invention provides apparatus and processes for producing liposomes. By providing a buffer solution in a first reservoir, and a lipid solution in a second reservoir, continuously diluting the lipid solution with the buffer solution in a mixing chamber produces a liposome. The lipid solution preferably comprises an organic solvent, such as a lower alkanol.

What is claimed is: 
     
         1 . A process for producing a lipid vesicle encapsulating one or more therapeutic agents within the lipid vesicle, said process comprising:
 providing an aqueous solution in a first reservoir;   providing an organic lipid solution in a second reservoir, wherein the lipids present in said organic lipid solution are solubilized in a lower alkanol at a concentration of about 75% v/v to 100% v/v, wherein said aqueous solution and/or said organic lipid solution comprises one or more therapeutic agents, and wherein said one or more therapeutic agents is selected from the group consisting of a nucleic acid, a protein, an antigen, paclitaxel, protax III, taxol, and mixtures thereof; and   mixing said organic lipid solution with said aqueous solution by introducing said organic lipid solution and said aqueous solution into a mixing environment at about equal flow rates;   wherein said mixing instantaneously produces a lipid vesicle encapsulating said one or more therapeutic agents within the lipid vesicle by diluting said lower alkanol to a concentration of between 45% v/v to about 60% v/v;   wherein the mixing environment includes a mixing chamber, wherein said aqueous solution and said organic lipid solution are introduced into the mixing chamber at an angle of between about 27° and about 180° relative to each other and mixed within the mixing chamber; and   wherein said lipid vesicle has a diameter of about 150 nm or less.   
     
     
         2 . The process of  claim 1 , further comprising diluting said lipid vesicle with a buffer solution wherein said lipid vesicle undergoes a continuous stepwise dilution to further stabilize the lipid vesicle. 
     
     
         3 . The process of  claim 1 , wherein said nucleic acid is selected from the group consisting of a plasmid, an antisense polynucleotide, a ribozyme, mRNA, tRNA, snRNA, siRNA, pre-condensed DNA, and mixtures thereof. 
     
     
         4 . The process of  claim 1 , wherein said aqueous solution comprises said nucleic acid, protein, antigen, or mixtures thereof. 
     
     
         5 . The process of  claim 1 , wherein said organic lipid solution comprises said paclitaxel, protax III, taxol, or mixtures thereof. 
     
     
         6 . The process of  claim 1 , wherein said angle is between about 27° and about 90° or between about 90° and about 180°. 
     
     
         7 . The process of  claim 1 , wherein said lower alkanol is selected from the group consisting of methanol, ethanol, propanol, butanol, pentanol, isomers thereof, and mixtures thereof. 
     
     
         8 . The process of  claim 1 , wherein the lipids present in said organic lipid solution are solubilized in said lower alkanol at a concentration of between about 80% v/v to about 90% v/v or 100% v/v. 
     
     
         9 . The process of  claim 1 , wherein the lipids present in said organic lipid solution comprise a phospholipid, cholesterol, a PEG-lipid, and a cationic lipid. 
     
     
         10 . The process of  claim 2 , further comprising concentrating said lipid vesicle by tangential flow ultrafiltration. 
     
     
         11 . An apparatus for producing a lipid vesicle encapsulating one or more therapeutic agents within the lipid vesicle, said apparatus comprising:
 a first reservoir for holding an aqueous solution;   a second reservoir for holding an organic lipid solution, wherein the lipids present in said organic lipid solution are solubilized in a lower alkanol at a concentration of about 75% v/v to 100% v/v, wherein said aqueous solution and/or said organic lipid solution comprises one or more therapeutic agents, and wherein said one or more therapeutic agents is selected from the group consisting of a nucleic acid, a protein, an antigen, paclitaxel, protax III, taxol, and mixtures thereof; and   a pump mechanism configured to pump said aqueous solution and said organic lipid solution into a mixing environment at about equal flow rates;   wherein said organic lipid solution mixes with said aqueous solution in the mixing environment to instantaneously produce a lipid vesicle encapsulating said one or more therapeutic agents within the lipid vesicle by diluting said lower alkanol to a concentration of between 45% v/v to about 60% v/v;   wherein the mixing environment includes a mixing chamber, wherein said aqueous solution and said organic lipid solution are introduced into the mixing chamber at an angle of between about 27° and about 180° relative to each other and mixed within the mixing chamber; and   wherein said lipid vesicle has a diameter of about 150 nm or less.   
     
     
         12 . The apparatus of  claim 11 , wherein said nucleic acid is selected from the group consisting of a plasmid, an antisense polynucleotide, a ribozyme, mRNA, tRNA, snRNA, siRNA, pre-condensed DNA, and mixtures thereof. 
     
     
         13 . The apparatus of  claim 11 , wherein said aqueous solution comprises said nucleic acid, protein, antigen, or mixtures thereof. 
     
     
         14 . The apparatus of  claim 11 , wherein said organic lipid solution comprises said paclitaxel, protax III, taxol, or mixtures thereof. 
     
     
         15 . The apparatus of  claim 11 , wherein said angle is between about 27° and about 90° or between about 90° and about 180°. 
     
     
         16 . The apparatus of  claim 11 , wherein said lower alkanol is selected from the group consisting of methanol, ethanol, propanol, butanol, pentanol, isomers thereof, and mixtures thereof. 
     
     
         17 . The apparatus of  claim 11 , wherein the lipids present in said organic lipid solution are solubilized in said lower alkanol at a concentration of between about 80% v/v to about 90% v/v or 100% v/v. 
     
     
         18 . The apparatus of  claim 11 , wherein the lipids present in said organic lipid solution comprise a phospholipid, cholesterol, a PEG-lipid, and a cationic lipid. 
     
     
         19 . The apparatus of  claim 11 , wherein the apparatus further comprises a tangential flow ultrafiltration system. 
     
     
         20 . The apparatus of  claim 11 , wherein the pump mechanism comprises a peristaltic pump.