Method and apparatus for liposome production

Abstract

A new method of producing liposomes is described using an in-line mixing system. The liposomes produced by this method find utility in numerous therapeutic applications.

1 . An apparatus for the continuous production of lipid vesicles by in-line mixing, said apparatus comprising: 
 (a) a lipid phase storage means capable of being maintained at a set temperature and a first pressurized transfer means for transferring the lipid phase from the storage means;    (b) an aqueous phase storage means capable of being maintained at a set temperature and a second pressurized transfer means for transferring the aqueous phase from the storage means;    (c) a mixing device comprising: a first metering system for receiving the lipid phase from the first pressurized transfer means; a second metering system for receiving the aqueous phase from the second pressurized transfer means; a pre-mixing system for preparing a pre-mixed formulation; a third pressurized transfer means for transferring the lipid phase from the first metering system to a first inlet orifice on the pre-mixing system and a fourth pressurized transfer means for transferring the aqueous phase from the second metering system to a second inlet orifice on the pre-mixing system; a mixer for preparing a mixed formulation comprising lipid vesicles, having a mixing chamber and an optional means for determining the optical properties of the mixed formulation; a means for transferring the pre-mixed formulation from the outlet orifice of the pre-mixing system to the mixing chamber; and an optional means for applying ultrasonic energy to the pre-mixing system, the mixing chamber or both; and    (d) a dispensing means for transferring the mixed formulation from the mixing chamber into a storage chamber.    
     
     
         2 . The apparatus of  claim 1  wherein said lipid vesicles are multilamellar or oligolamellar.  
     
     
         3 . The apparatus of  claim 1  which further comprises a means for homogenization or sonication located between the dispensing means and the storage chamber.  
     
     
         4 . The apparatus of  claim 2  wherein said lipid vesicles are unilamellar.  
     
     
         5 . The apparatus of  claim 1  wherein the lipid phase comprises an active agent.  
     
     
         6 . The apparatus of  claim 1  wherein the lipid phase storage means is capable of being maintained at a set temperature by a first temperature control means and the aqueous phase storage means is capable of being maintained at a set temperature by a second temperature control means.  
     
     
         7 . The apparatus of  claim 6  wherein said lipid phase storage means is maintained at a temperature within the range of about 20 to 80° C.  
     
     
         8 . The apparatus of  claim 6  wherein said aqueous phase storage means is maintained at a temperature within the range of about 20 to 80° C.  
     
     
         9 . The apparatus of  claim 1  wherein the means for determining the optical properties of the mixed formulation is configured so as to control the first and second temperature control means and the first and second metering systems.  
     
     
         10 . The apparatus of  claim 1  which further comprises additional storage means for a second lipid phase, a pre-mixed lipid phase-aqueous phase mixture or a pre-formed lipid vesicle phase.  
     
     
         11 - 33 . (canceled)  
     
     
         34 . A method for the continuous production of lipid vesicles by in-line mixing, said method comprising: 
 (a) preparing a lipid phase and storing the lipid phase in a first storage means that is maintained at a set temperature;    (b) preparing an aqueous phase and storing the aqueous phase in a second storage means that is maintained at a set temperature;    (c) combining the lipid and aqueous phases by means of a mixing device having first and second metering systems, a pre-mixing system and a mixer, by: transferring the lipid phase from the first storage means to the first metering system by a first pressurized transfer means and transferring the aqueous phase from the second storage means to the second metering system by a second pressurized transfer means; transferring the lipid phase from the first metering system to a first inlet orifice in the pre-mixing system by a third pressurized transfer means and transferring the aqueous phase from the second metering system to a second inlet orifice in the pre-mixing system by a fourth pressurized transfer means; wherein the lipid phase and aqueous phases are transferred to the pre-mixing system with a high velocity creating turbulent flow; combining the lipid and aqueous phases in the pre-mixing system by shear mixing under conditions to insure that the lipid phase becomes fully hydrated by the aqueous phase to form a pre-mixed formulation; and transferring the pre-mixed formulation from an outlet orifice of the pre-mixing system to the mixer;    (d) forming a mixed formulation containing lipid vesicles, in the mixer by causing the pre-mixed formulation to traverse the mixer;    (e) optionally measuring the optical properties of the lipid vesicles; and    (f) dispensing the mixed formulation from the mixer into a storage chamber, into a means for further modification of the properties of the lipid vesicles, or into a means of packaging the mixed formulation.    
     
     
         35 . The method of  claim 34  wherein said lipid vesicles are multilamellar.  
     
     
         36 . The method of  claim 34  which further comprises a homogenization or sonication step after the dispensing step.  
     
     
         37 . The method of  claim 36  wherein said lipid vesicles are unilamellar.  
     
     
         38 . The method of  claim 34  wherein the lipid phase comprises an active agent.  
     
     
         39 . The method of  claim 34  wherein said first storage means is maintained at a temperature within the range of about 20 to 80° C.  
     
     
         40 . The method of  claim 34  wherein-said second storage means is maintained at a temperature within the range of about 20 to 80° C.  
     
     
         41 . The method of  claim 34  wherein the step of measuring optical properties is by means of an optical transmission sensing device using a photoresistor or phototransistor, which provides a control signal to a controlling computer or other process control device.  
     
     
         42 . The method of  claim 34  which further comprises the addition of a second lipid phase, a pre-mixed lipid phase-aqueous phase mixture or a pre-formed lipid vesicle phase.  
     
     
         43 . The method of  claim 34  wherein the first and second storage means are continuously replenished with the lipid and aqueous phases, respectively.  
     
     
         44 - 57 . (canceled)