Liposome composition and method for producing same

Abstract

Provided are a liposome composition in which an osmotic pressure of an inner water phase is 2-fold to 8-fold relative to the osmotic pressure of an outer water phase, and which encapsulates a water-soluble drug in a dissolved state, and also exhibits excellent preservation stability; and a method for producing the same. According to the present invention, it is possible to provide a liposome composition, including liposomes obtained from lipids dissolved and emulsified in an organic solvent, each of which has an inner water phase and an aqueous solution which constitutes an outer water phase and in which the liposomes are dispersed, in which each of the liposomes encapsulates a water-soluble drug in a dissolved state, and an osmotic pressure of the inner water phase is 2-fold to 8-fold relative to the osmotic pressure of the outer water phase; and a method for producing the same.

What is claimed is: 
     
         1 . A liposome composition, comprising:
 liposomes obtained from lipids dissolved and emulsified in an organic solvent, each of which has an inner water phase and an aqueous solution which constitutes an outer water phase and in which the liposomes are dispersed,   wherein each of the liposomes encapsulates a water-soluble drug in a dissolved state, and an osmotic pressure of the inner water phase is 2-fold to 8-fold relative to the osmotic pressure of the outer water phase.   
     
     
         2 . The liposome composition according to  claim 1 , wherein the liposome has a single lamellar structure. 
     
     
         3 . The liposome composition according to  claim 1 , wherein an average particle size of the liposomes is 5 nm to 100 nm. 
     
     
         4 . The liposome composition according to  claim 2 , wherein an average particle size of the liposomes is 5 nm to 100 nm. 
     
     
         5 . The liposome composition according to  claim 1 , wherein the liposome contains at least hydrogenated soybean phosphatidylcholine, 1,2-distearoyl-3-phosphatidylethanolamine-polyethylene glycol, and cholesterol. 
     
     
         6 . The liposome composition according to  claim 2 , wherein the liposome contains at least hydrogenated soybean phosphatidycholine, 1,2-distearoyl-3-phosphatidylethanolamine-polyethylene glycol, and cholesterol. 
     
     
         7 . The liposome composition according to  claim 3 , wherein the liposome contains at least hydrogenated soybean phosphatidylcholine, 1,2-distearoyl-3-phosphatidylethanolamine-polyethylene glycol, and cholesterol. 
     
     
         8 . The liposome composition according to  claim 4 , wherein the liposome contains at least hydrogenated soybean phosphatidylcholine, 1,2-distearoyl-3-phosphatidylethanolamine-polyethylene glycol, and cholesterol. 
     
     
         9 . A pharmaceutical composition comprising the liposome composition according to  claim 1 . 
     
     
         10 . A pharmaceutical composition comprising the liposome composition according to  claim 2 . 
     
     
         11 . A pharmaceutical composition comprising the liposome composition according to  claim 3 . 
     
     
         12 . A pharmaceutical composition comprising the liposome composition according to  claim 4 . 
     
     
         13 . A pharmaceutical composition comprising the liposome composition according to  claim 5 . 
     
     
         14 . A pharmaceutical composition comprising the liposome composition according to  claim 6 . 
     
     
         15 . A pharmaceutical composition comprising the liposome composition according to  claim 7 . 
     
     
         16 . A pharmaceutical composition comprising the liposome composition according to  claim 8 . 
     
     
         17 . A method for producing a liposome composition, comprising:
 an emulsifying step of emulsifying lipids dissolved in an organic solvent to form liposomes, without a drying and solidifying step;   a drug loading step of encapsulating a water-soluble drug in the liposomes obtained in the emulsifying step; and   an osmotic pressure adjusting step of adjusting an osmotic pressure of an inner water phase of the liposome to 2-fold to 8-fold relative to the osmotic pressure of an outer water phase.   
     
     
         18 . The method for producing a liposome composition according to  claim 17 , wherein the liposomes obtained after the emulsifying step are used in a next step without extrusion processing. 
     
     
         19 . The method for producing a liposome composition according to  claim 17 , wherein the drug loading step and the osmotic pressure adjusting step are carried out simultaneously. 
     
     
         20 . The method for producing a liposome composition according to  claim 18 , wherein the drug loading step and the osmotic pressure adjusting step are carried out simultaneously.