Production of multivesicular liposomes

Abstract

Multivesicular liposomes are prepared at commercial scales by combining a first w/o emulsion with a second aqueous solution to form a w/o/w emulsion using a static mixer. Solvent is removed from the resulting emulsion to form multivesicular liposome-containing compositions. Further optional process steps include primary filtration and secondary cross-flow filtration. The products produced according to the processes of the invention can be produced through a series of aseptic steps.

1 . A process for preparing a multivesicular liposomal particle composition, the process comprising:
 a) providing a volume of first emulsion by mixing a volume of a first aqueous phase and a volume of a volatile water-immiscible solvent phase, said solvent phase comprising at least one amphipathic lipid and at least one neutral lipid;   b) mixing and emulsifying said first emulsion and a volume of a second aqueous phase in a mixer to provide a volume of a second emulsion, said second emulsion comprising a continuous aqueous phase; and   c) removing the volatile water-immiscible solvent from the second emulsion to form a volume of multi vesicular liposomal particle composition,   wherein all steps are carried out under aseptic conditions, and wherein all solutions are sterile filtered, and wherein the multivesicular liposomal particle composition is immediately suitable for administration into humans.   
     
     
         2 . The process of  claim 1 , wherein the mixer is a dynamic or static mixer. 
     
     
         3 . The process of  claim 2 , wherein the static mixer is of Kenics or Koch design. 
     
     
         4 . The process of  claim 3 , wherein the first emulsion and second aqueous solution are passed through the mixer at a linear velocity of from about 100 cm/min to about 500 cm/min. 
     
     
         5 . The process of  claim 1 , wherein the volume ratio of the first aqueous phase to the water-immiscible solvent phase is from about 0.33 to about 1.6. 
     
     
         6 . The process of  claim 1 , wherein the volume ratio of the first emulsion to the second aqueous phase is from about 0.05 to about 0.5. 
     
     
         7 . The process of  claim 1 , wherein the at least one amphipathic lipid is selected from the group consisting of phosphatidylcholines, phosphatidylethanolamines, sphingomyelins, lysophosphatidylcholines, lysophosphatidylethanolamines, phosphatidylglycerols, phosphatidylserines, phosphatidylinositols, phosphatidic acids, cardiolipins, acyl trimethylammonium propane, diacyl dimethylammonium propane, stearylamine, and ethyl phosphatidylcholine. 
     
     
         8 . The process of  claim 1 , wherein the at least one neutral lipid is selected from the group consisting of glycerol esters, glycol esters, tocopherol esters, sterol esters, alkanes and squalenes. 
     
     
         9 . The process of  claim 1 , wherein the second aqueous phase further comprises at least one sugar. 
     
     
         10 . The process of  claim 1 , wherein the second aqueous phase further comprises at least one amino acid. 
     
     
         11 . The process of  claim 1 , further comprising primary filtration of the multivesicular liposomal particle composition. 
     
     
         12 . The process of  claim 11 , wherein the primary filtration comprises:
 a) a first concentration of the multivesicular liposomal particle composition, resulting in a concentration increase of from 2-6 times; and   b) a buffer exchange, resulting in a pH of the multivesicular liposomal particle composition of between about 5 and about 8.   
     
     
         13 . The process of  claim 12 , further comprising a second concentration step. 
     
     
         14 . The process of  claim 11 , wherein the primary filtration is a carried out by cross-flow filtration with a hollow fiber filter. 
     
     
         15 . The process of  claim 14 , wherein the primary filtration is conducted at a transmembrane pressure of from about 0.1 psi to about 7 psi. 
     
     
         16 - 22 . (canceled) 
     
     
         23 . The process of  claim 1 , further comprising potency adjustment of the multivesicular liposomal particle composition. 
     
     
         24 . The process of  claim 23 , wherein the potency adjustment is carried out secondary filtration. 
     
     
         25 . The process of  claim 23 , wherein the potency adjustment is carried out by decanting the multivesicular liposomal particle composition. 
     
     
         26 . The process of  claim 1 , wherein said solvent removal comprises contacting the second emulsion with an inert gas flow. 
     
     
         27 - 32 . (canceled) 
     
     
         33 . The process of  claim 1 , wherein the first aqueous phase comprises a physiologically active substance, and the multivesicular liposomal particle composition comprises an encapsulated physiologically active substance. 
     
     
         34 . The process of  claim 33 , wherein the physiologically active substance is selected from the group consisting of antianginas, antiarrhythmics, antiasthmatic agents, antibiotics, antidiabetics, antifungals, antihistamines, antihypertensives, antiparasitics, antineoplastics, antitumor drugs, antivirals, cardiac glycosides, hormones, immunomodulators, monoclonal antibodies, neurotransmitters, nucleic acids, proteins, radio contrast agents, radionuclides, sedatives, analgesics, steroids, tranquilizers, vaccines, vasopressors, anesthetics, peptides, prodrugs and pharmaceutically acceptable salts of the same. 
     
     
         35 . The process of  claim 34 , wherein the physiologically active substance is selected from cytarabine, insulin, paclitaxel, 5-fluorouracil, floxuridine, morphine, hydromorphine, dexamethasone, methotrexate, bleomycin, vincristine, vinblastine, IgF-1, bupivacaine and amikacin. 
     
     
         36 - 48 . (canceled) 
     
     
         49 . A process for preparing a multivesicular liposomal particle composition, the process comprising:
 a) providing a volume of first emulsion by mixing a volume of a first aqueous phase and a volume of a volatile water-immiscible solvent phase, said solvent phase comprising at least one amphipathic lipid and at least one neutral lipid;   b) mixing and emulsifying said first emulsion and a volume of a second aqueous phase in a mixer to provide a volume of a second emulsion, said second emulsion comprising a continuous aqueous phase; and   c) removing the volatile water-immiscible solvent from the second emulsion to form a volume of multivesicular liposomal particle composition,   wherein the multivesicular liposomal particle composition is sterilized before filling, and wherein the multivesicular liposomal particle composition is immediately suitable for administration into humans.   
     
     
         50 . A multivesicular liposomal particle composition made by the process of  claim 1 . 
     
     
         51 . The process of  claim 23 , wherein the volume of multivesicular liposomal particle composition is pooled and further processed by multiple batch processing.