Liposome extruder easy to operate

Abstract

The aim of the invention is to provide a device (0) for extruding liposomes via a filter element (5) at elevated fluid pressure (P), which can be easily and quickly operated in a clean room environment. The basic design principle of the device (0) is that the pressure chamber (3) is similar to a hyacinth-bean-shaped ellipsoid (E). The pressure chamber (3) consists of two hemispheres, namely a fixed socket (3a) and a releasable cap (3b). The pressure vessel (3) can be opened by lifting the cap (3b). The device (0) is equipped with an integrated guide groove (2) which is designed to vertically guide the cap (3b). The idea of such a guide groove (2) is to maintain alignment of the cap (3b) with the socket (3a) when the cap (3b) is released. Since the guide groove (2) only allows vertical translation of the cap (3b), tilting and deflection of the cap (3b) are eliminated. The oblate shape of the cap (3b) further supports this effect. This series of factors contribute to removal and replacement of the cap (3b) in a short period of time without the need for complex alignment.

Description

Technical Field

[0001] The present invention relates to a device for extruding liposomes and a method for producing liposomes by means of the device. Background Art

[0002] Liposomes are essentially spherical structures with a diameter of 25 nm to 1 μm. They contain one or more concentric lipid bilayers surrounding an aqueous interior, so-called lipid vesicles. Liposomes are produced by dispersing lipids in an aqueous solution. Suitable lipids are particularly phosphatidylcholine (lecithin), phosphatidylethanolamine or phosphatidylserine (cephalin). Liposomes are used as carriers for active substances in pharmaceuticals, cosmetics or health products that are selectively enriched in certain organs and cell populations.

[0003] Guo et al. provide an overview of methods for preparing liposomes:

[0004] Guo,P.,Huang,J.,Zhao,Y.,Martin,CR,Zare,RN,Moses,MA: NanomaterialPreparation by Extrusion through Nanoporous Membranes.Small 2018,14,1703493.DOI:10.1002 / smll.201703493

[0005] A key property of liposomes is their size distribution. In particular, liposomes intended for pharmaceutical, cosmetic, or health product applications need to have a size distribution that falls within a tight range. This means that the actual size of individual liposomes should not deviate significantly from a specific average. Therefore, determining the appropriate size is an important step in the liposome production process.

[0006] A common method for controlling liposome size is extrusion. Here, a feed dispersion comprising liposome precursors dispersed in a liquid dispersion medium is first prepared. Fluid pressure is applied to this feed dispersion. The pressurized feed dispersion is then extruded through a porous filter element with a defined pore size. During the extrusion process, the size of the precursor liposomes decreases. In addition to pore size, energy input is also a key parameter in the extrusion process. Liposomes are fluid systems. They can pass through, for example, a 100 nm membrane and then form particles with an average size of 250 nm. Therefore, in order to effectively reduce their diameter, liposomes typically require more than one pass through the extruder. Such liposome extrusion processes are generally understood as purely physical operations without chemical interactions. Therefore, the chemical composition of the target liposomes is already determined by the liposome precursors.

[0007] In commercial liposome extrusion processes, dense polycarbonate sheets are used as filter elements. The porosity of these items is typically 100 nm to 5 μm.

[0008] The size of proliposomes is usually in the range of 50 nm to 10 μm. In order to achieve the extrusion of proliposomes through dense filter elements, elevated pressure is necessary. 5 Pa to 40*10 5 Pa (20 to 40 bar) fluid pressure, while the high pressure method achieves 100*10 5 Pa to 200*10 5 Nominal fluid pressure of Pa (100 to 200 bar).

[0009] The apparatus used to carry out such a liposome extrusion method is called a liposome extruder. The basic components of a liposome extruder are a container into which a liquid dispersion of the precursor is fed, a device for applying fluid pressure to the precursor contained in the container, and a porous filter element through which the precursor is extruded from the container.

[0010] To withstand the elevated pressures, the mechanical design of the liposome extruder must be robust enough. For safety reasons, the extruder design must be able to accommodate internal pressures even higher than the extrusion pressure. Due to general regulations for pressure vessels, the extruder must be designed to withstand internal pressures 1.3 to 1.7 times the nominal operating pressure. Therefore, the liposome extruder needs to be designed to be very heavy to withstand such high pressures.

[0011] From WO 2021 / 207841 A1 or from WO 01 / 05373 A1 Figure 4 Examples of liposome extruders are known from the literature and related specifications. Both of the articles described in the respective documents are equipped with a pressure chamber consisting of two hemispheres, i.e., fixed sockets and a cap releasably coupled to the sockets. The pressure chamber has a one-way inlet defined by a back pressure valve and an outlet defined by a filter element. The precursor feed is introduced into the pressure chamber via the inlet. In the pressure chamber, fluid pressure is applied to the feed. The fluid pressure drives the precursor mixture out of the pressure chamber through the filter element to facilitate extrusion.

[0012] In routine operation, the liposome sizing process using such an extrusion device is run until the filter element loses permeability due to clogging. The device is then depressurized, the cap and socket are released from each other, the cap is removed, the filter element with reduced permeability is replaced with a new filter, the cap and socket are recoupled to each other, the device is repressurized, and liposome extrusion continues.

[0013] When producing liposomes for pharmaceutical, cosmetic or health product applications, strict requirements regarding hygiene conditions need to be met. Therefore, liposome extruders are installed in clean rooms that only workers wearing protective clothing can enter. For pharmaceutical applications, when handling potent drugs (such as the anticancer drug doxorubicin), extrusion must also be carried out under secondary containment to avoid contaminating production personnel. Due to hygiene requirements, the handling of heavy extruder components is strenuous: for example, the cap of a typical high-pressure chamber weighs up to 50 kg. Therefore, a crane is required for operation. Operating the crane and changing the filter element while wearing high-grade protective clothing and / or under secondary containment is very tiring for the workers. In particular, precise alignment of the cap with the socket to achieve a secure seal is very strenuous. Therefore, changing the filter element of a conventional liposome extruder under enhanced hygiene requirements takes a long time of 20 to 30 minutes, even with the participation of two operators. Unplanned and extended setup times can be the root cause of violations of good manufacturing practices (GMP deviations). Summary of the Invention

[0014] In view of this, an object of the present invention is to provide a device for extruding liposomes through a filter element under elevated fluid pressure, which can be easily and quickly operated in a clean room environment. In particular, it should be possible to replace a worn filter element within a short time.

[0015] This object is achieved by a device for extruding liposomes, comprising the following components:

[0016] A device for applying a fluid pressure P to a liquid medium, wherein the fluid pressure P is 20*10 5 Pa to 200*10 5 Pa;

[0017] A frame including vertical guideways;

[0018] A pressure chamber comprising a socket and a cap releasably coupled to each other, wherein the socket is fixed to the frame, wherein the cap is vertically guided by the vertical guide groove, wherein the pressure chamber is designed to withstand pressure from a P b =S*PCalculated internal fluid pressure P b , wherein S is a reasonable safety factor, preferably selected from the range of 1.3 to 1.7, and wherein the cap comprises an inner surface approximately corresponding to an ellipsoid defined by the following equation:

[0019] x 2 / a 2 +y 2 / b 2 +z 2 / c 2 =1

[0020] where x, y, and z are Cartesian coordinates, where x and y are horizontally oriented, and z is vertically oriented, where a, b, and c are defined as the lengths of the semi-axes of the ellipsoid, and where the pressure chamber is designed such that the lengths a, b, c of the semi-axes of the ellipsoid satisfy the following two conditions: c < a and c < b; where the cap (x) is designed such that the lengths a and b of the semi-axes of the ellipsoid (E) satisfy the condition a = b < 500 mm or a = b < 300 mm;

[0021] · A filter support removably mounted in the socket;

[0022] · At least one porous filter element defining an outlet of the pressure chamber, where the filter element includes open pores having a diameter D, where the pore diameter D is 50*10 -9 m to 50*10 -6 m or 80*10 -9 m to 5*10 -6 m, whereby the filter element is received in the filter support.

[0023] The inner surface of the cap approximating an ellipsoid defined by a specified equation means a partial area of the total inner surface of the cap. According to a beneficial version of the device, the (partial) inner surface according to the specified equation covers at least 60%, preferably at least 70%, and most beneficially at least 80% of the total inner surface of the cap.

[0024] The device is the first subject of the present invention.

[0025] The basic design principle of the present device is that the pressure chamber has a cap with an inner surface approximating an ellipsoidal shape, whereby the vertical diameter of the ellipsoid is smaller than the horizontal diameter. Thus, the ellipsoid is oblate, similar to a lentil. The cap is part of the pressure chamber consisting of two hemispheres, namely the fixed socket and the cap (releasable). The pressure vessel can be opened by lifting the cap. The extruder is equipped with an integrated guide groove designed to vertically guide the cap. The idea of such a guide groove is to maintain the horizontal alignment of the cap with the socket when releasing the cap. In addition, the axial position of the cap relative to the socket is maintained. Both contribute to rematching the two hemispheres when mounting the cap onto the socket: Since the guide groove only allows vertical translation of the cap, tilting and offset of the cap are excluded. The oblate shape of the cap further supports this effect: Since the horizontal diameter is enlarged, the moment of tilting out of the horizontal plane is higher, and the cap is better stabilized in the horizontal plane than an ideal sphere having the same diameter in all directions. This series of factors contributes to removing and replacing the cap in a short time without the need for complex alignment.

[0026] Another advantageous feature of the device according to the present invention is the filter holder, which houses the porous filter element. The filter element is intended to be used for only a limited operating time. Its lifespan depends on its permeability, which decreases over time due to clogging. The filter holder is intended to be used permanently. Since it is removably mounted to the socket, it can be quickly removed once the pressure vessel has been opened by lifting the cap. Since the filter holder is not under pressure, it can be designed to be lightweight. Due to its low weight, a single operator can easily remove the filter holder by hand. The actual replacement of the filter element can be carried out at a location far away from the location where the socket is fixed. In particular, it is possible to move the filter holder to a remote location with better ergonomic conditions. There, the worn-out filter element is replaced with a new one, and the filter holder is returned to the socket.

[0027] In short, the design of the liposome extruder of the present invention allows workers to change filter elements faster and with less effort, even in a clean room environment, compared to conventional equipment.

[0028] According to the inventive concept of the oblate ellipsoid-shaped cap of the pressure chamber, the vertical semi-axis c of the ellipsoid is shorter than the horizontal semi-axes a and b. However, the horizontal semi-axes a and b are not necessarily the same. Therefore, in the horizontal plane, the pressure chamber may have an elliptical circumference. But in order to optimize the ability to be tightened, it is ideal to have an ideal circular circumference in the horizontal plane. Therefore, according to a preferred embodiment, the cap of the pressure chamber is designed so that the lengths a and b of the semi-axes of the ellipsoid satisfy the condition a=b. Under the same horizontal semi-axes a, b, the circumference in the horizontal plane is circular. According to a preferred embodiment, the dimensions of a and b are lower than 500 mm or even lower than 300 mm, and the lower limit of a and b may be 100 mm. The vertical dimension c (the length of the z semi-axis) may be between 10 mm and 20 mm.

[0029] For good operability, the weight of the cap should at least be minimized. Therefore, the material needs to be reduced. The low amount of material leads to high mechanical stress under internal pressure. To ensure safety, the shape of the pressure chamber needs to be designed to optimize stress. Stress optimization can be achieved by using a convex ellipsoid. "Convex" means that the imaginary line segment between two points on the surface of the pressure chamber's ellipsoid extends inside the pressure chamber. At the same pressure resistance, a convexly curved pressure chamber can be constructed with less weight than a concavely curved pressure chamber.

[0030] According to a preferred embodiment of the device, the filter holder consists of a substantially flat support screen and one or more filter elements, whereby the flat support screen extends substantially horizontally. Such a flat support screen can be fitted very comfortably onto the socket. It preferably extends within the horizontal interface between the socket and the cap. The support screen can be equipped with a single filter element or an array of several filter elements arranged in parallel.

[0031] The support screen itself may be porous and configured to allow the liquid medium to flow through the filter holder.

[0032] Optionally, the filter holder further comprises at least one flat porous drain element located between the support screen and the filter element. The pore size of the drain element should be larger than the pore size of the filter element, but still smaller than the pore size of the flat support screen. Such a drain element prevents the filter element from squeezing into the pores of the support screen.

[0033] Preferably, the filter holder comprises at least two handles for gripping to remove the filter holder from the socket. In particular, if the filter holder is configured as a flat supporting screen, such a lightweight filter holder can be manually manipulated if equipped with such handles.

[0034] However, if the extrusion pressure requires a heavier construction, the filter holder should be made of a material with a higher magnetic permeability than the socket. This allows the filter holder to be picked up using a lifting magnet attached to a crane. If the magnetic permeability of the socket were the same as that of the filter holder, the magnetic lift would stick to both components, making it impossible to release the filter holder. Preferably, the filter holder is made of stainless steel, while the socket is made of diamagnetic stainless steel. Examples of suitable steel grades are: 1.4016, 1.3813, 1.3952, 1.3964, 1.3974.

[0035] The filter element may be of an approved design, ie configured as a flat plate made of a porous material selected from the group consisting of polycarbonate, sintered metal and metal foil. The flat plate preferably has a circular shape.

[0036] The shape of the filter element is preferably flat and circular (disc-shaped). A typical disc diameter of the filter element may be between 20 mm and 50 mm, for example 25 mm. The pore diameter D of the filter element should be 50*10 -9 m to 50*10 -6 m or 80*10 -9 m to 5*10 -6 m. For example, a pore diameter of 0.1 μm can be used. The pore size is given by the filter element supplier and can be verified by optical means or by transmission electron microscopy (TEM) or by scanning electron microscopy (SEM).

[0037] The device of the present invention works with commercially available filter elements. For example, Whatman Nuclepore polycarbonate hydrophilic membranes can be used as filter elements. The latter are available from Cytiva Europe GmbH, Freiburg, Germany.

[0038] The guide slots are designed to maintain the correct alignment of the cap relative to the socket. However, they do not provide the force required to lift the cap. This force must be applied manually by the operator or, if the cap is heavy, by an external crane. To expedite the handling of heavy caps, the device preferably includes a lifting mechanism designed to lift the cap. This mechanism eliminates the need for an external crane, though it may be necessary if the cap is too heavy to be handled manually.

[0039] Preferably, the lifting mechanism is functionally separated from the guide channel. This construction method allows for precise guidance compared to an integrated design. A separate design means that the vertical guidance function is achieved by a separate component from the lifting function.

[0040] According to a further improved embodiment, the frame of the device comprises one, preferably exactly one, vertically upright beam extending to the outside of the pressure chamber, wherein the beam forms a guide rail, and wherein the cap is equipped with a guide sleeve (rider) which is vertically movable on the guide rail, whereby the guide channel consists of the guide rail and the guide sleeve. Compared to a multi-beam design, such a single-beam construction makes it easier to reach the opened pressure chamber in order to remove the filter holder over a wide sector.

[0041] Preferably, the socket and the cap are releasably coupled to each other by a threaded connection comprising a plurality of vertically extending bolts located on a horizontally arranged bolt circle, whereby the effective axis of the vertical guide slots points towards the circumference of the bolt circle. Such a design has been found to be stable and easy to achieve.

[0042] If a bolt connection is used, at least one bolt can be pivotally mounted to the socket, wherein the axis of rotation between the bolt and the socket extends horizontally. The cap is equipped with a hook-shaped receiving portion for the nut threaded onto the bolt. In particular, high-pressure chambers require heavy screws, which also require manipulation. If the bolts pivot horizontally, the operator does not need to introduce the heavy bolts into the threaded holes (which is very time-consuming). In this embodiment, the bolts are simply pivoted so that the nut is received by the corresponding hook of the cap. The number of turns for fixing such a bolt connection is less than the number of turns for screwing the bolt vertically into the threaded hole. This makes the operation faster. In addition, it is impossible to lose a bolt. Preferably, all bolts pivot horizontally in this way.

[0043] Due to its robust construction, the device of the present invention can be installed in 20*10 5 Pa to 200*10 5 Pa. This covers the wide pressure range of 20*10 5 Pa to 40*10 5 Pa (20 to 40 bar) of fluid pressure, also covers the realization of 100*10 5Pa to 200*10 5 High pressure process with nominal fluid pressure of 100 to 200 bar. 5 Pa to 70*10 5 Intermediate pressures between Pa are also possible.

[0044] Another subject of the present invention is a method for preparing target liposomes from liposome precursors using the device of the present invention. This method comprises the following steps:

[0045] a) providing the device of the present invention;

[0046] b) providing a feed dispersion comprising a liposome precursor dispersed in a liquid dispersion medium;

[0047] c) applying 20*10 5 Pa to 200*10 5 a hydraulic pressure P of Pa to obtain a pressurized feed dispersion;

[0048] d) extruding the pressurized feed dispersion through a filter element of a device to obtain an extruded dispersion comprising target liposomes dispersed in a dispersion medium;

[0049] e) Optional: Recovering the desired liposomes from the extruded dispersion.

[0050] The production method of the present invention is carried out similarly to conventional liposome extrusion methods. It is only necessary to replace conventional equipment with the liposome extruder of the present invention. Therefore, implementation of this novel method can be achieved quickly. Since the extrusion pressure and filter element are conventional, the same product quality is expected. Therefore, during normal operation, the liposome extrusion method of the present invention achieves the same results as conventional methods.

[0051] The benefits over conventional preparation methods are achieved when the method is continued until a defined degree of clogging of the filter element is reached. This is a normal phenomenon caused by clogging of the filter element. Due to the inventive design of the device used, a worn filter element can be quickly and easily replaced by the following steps: after reaching the defined degree of clogging, the device is depressurized, the cap and socket are released from each other, the cap is raised, the filter holder containing the filter element with reduced permeability is replaced with a new filter holder containing a new filter element, the cap is lowered, the socket and cap are recoupled to each other, the device is repressurized, and the method is continued.

[0052] A particular benefit is that the cap does not need to be aligned with the socket in a complicated manner before recoupling, as the horizontal and axial position of the cap relative to the socket is maintained by the guide groove. In addition, the filter element is removed together with the filter holder. The filter holder can be transported to a place with optimized ergonomic conditions to remove the filter element from the filter holder and insert a new filter element. This is particularly beneficial if the filter holder contains many individual filter elements that need to be replaced. In addition, a new filter holder with a new filter element can be prepared during the operation of the device. When the operation process stops, only the filter holder carrying the old filter element is replaced with a new filter holder. This is even faster than replacing the filter element in the filter holder during shutdown. However, this requires at least two filter holders, the first one in operation and the second one in preparation for replacing the first one. Therefore, the "new filter holder" in the sense of the present invention can be the same item as the filter holder that previously carried the old filter element, or a second item that is not currently in operation.

[0053] Due to the superior operability of the device of the present invention, filter element replacement can be completed in a short time. Specifically, the steps of depressurizing the device, releasing the cap and socket from each other, lifting the cap, replacing the filter holder containing the reduced permeability filter element with a new filter holder containing a new filter element, lowering the cap, re-coupling the socket and cap, and re-pressurizing the device can be performed in 5 minutes or less.

[0054] If the filter holder is made of a material with a higher magnetic permeability than the socket, it can be removed from the socket with the help of a magnetic manipulator. This magnetic manipulator can be a magnetic lifter attached to a crane. This makes it easy to remove heavy filter holders that are difficult to carry by hand. It is worth mentioning that the filter holder is lighter than the pressure chamber cap because it is placed inside the chamber and therefore does not need to bear the entire internal pressure like the cap and socket do. The pressure is concentrated only on the filter element area. As a result, the filter element can be lighter in size.

[0055] The invention is intended to be explained in more detail by way of example with the aid of the drawing, which shows an exemplary embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings show in particular:

[0057] Figure 1 : Device, cap lifted, perspective view;

[0058] Figure 2 : Device, cap lifted, side view;

[0059] Figure 3 : Device, cap lifted, from Figure 2sectional view of

[0060] Figure 4 : Device, top view;

[0061] Figure 5 : Device, cap coupled to socket, perspective view;

[0062] Figure 6 : Device, cap coupled to socket, cross-sectional view;

[0063] Figure 7 : Filter holder, top view;

[0064] Figure 8 : Filter holder, cross-sectional view;

[0065] Figure 9 : Ellipsoid E, perspective view.

[0066] For general orientation, in some figures, the directions of the Cartesian coordinates x, y, and z are indicated. Typically, x and y are oriented horizontally, while the z axis is parallel to the direction of gravity and is therefore oriented vertically.

[0067] A perspective view of an embodiment of the device 0 of the present invention (the so-called liposome extruder) is shown in FIG. Figure 1 Device 0 includes a fixed frame 1 provided with a vertical guide channel 2. Guide channel 2 consists of a guide rail 2a fixed to a beam of frame 1 and a movable guide sleeve 2b. Guide sleeve 2b is movable only in the vertical direction, i.e., the z-axis. Guide rail 2b constitutes the non-movable portion of vertical guide channel 2. Guide sleeve 2b and guide rail 2a can be designed as dovetail joints (not shown).

[0068] The central component of the device is the pressure chamber 3, which consists of a socket 3a and a cap 3b. Socket 3a is fixed to frame 1, while cap 3b is fixed to guide sleeve 2b of vertical guide slot 2, thus allowing movement only in the vertical (z) direction. Movement in the z direction is solely translational. All other movement of cap 3b (translation in the x or y axis or pivoting about the x, y, or z axis) is restricted by vertical guide slot 2.

[0069] The socket 2a is provided with a receiving portion for the filter holder 4. The filter holder 4 is configured as a substantially flat screen containing a plurality of inserted filter elements 5. The latter are Figure 7 Each filter element 5 is configured as a flat plate made of porous polycarbonate.

[0070] Another component of device 0 is a device for applying fluid pressure (not shown) and a lifting mechanism 6 for lifting the cap 2b. The lifting mechanism 6 is functionally separated from the vertical guide groove 2. This means that the lifting mechanism 6 applies a force to lift and hold the cap 2b, while the guide groove only controls the direction of movement. The lifting mechanism 6 can be a worm gear with a motor or a hydraulic piston.

[0071] During operation ( Figure 5 、 Figure 6 、 Figure 7 ), the filter support 4 containing the filter element 5 is placed into the socket 3a. The cap 3b is placed on the socket 3a, and these two components 3a, 3b are fixed to each other by means of a bolt connection 7. The inlet of the pressure chamber 3 is established by a device for applying pressure (not shown), while the outlet of the pressure chamber is defined by the filter element 5.

[0072] As Figure 6 shown, the pressure chamber 3 composed of the socket 3a and the installed cap 3b defines an inner cavity 8 having an ellipsoidal shape. In particular, the inner surface 9 of the cap 3b approximates an ellipsoid E defined by the following equation:

[0073] x 2 / a 2 +y 2 / b 2 +z 2 / c 2 =1

[0074] In this equation, x, y, and z are Cartesian coordinates, and a, b, and c are defined as the lengths of the semi-axes of the ellipsoid. The ellipsoid E and its dimensions are shown in Figure 9 . The inner surface 9 of the cap 3b defining the edge of the inner cavity 8 is configured such that the lengths of the semi-axes of the ellipsoid a, b, c satisfy two conditions: c < a = b. This means that the ellipsoid E is circular in a vertical view but oblate in any horizontal view.

[0075] To extrude liposomes, a feed dispersion containing liposome precursors is fed into the cavity of the closed pressure chamber and a fluid pressure P is applied. The fluid pressure P can be applied hydraulically or pneumatically. The high-pressure apparatus is in the range of 100 * 10 5 Pa to 200 * 10 5 Pa, while the medium-pressure apparatus is between 20 * 10 5 Pa and 40 * 10 5 Pa.

[0076] The dimensions of the pressure chamber 3, in particular the socket 3a, the cap 3b, and the bolt connection 7, are set to withstand the higher internal pressure P bFor safety reasons, the pressure chamber can withstand an internal pressure P up to 1.6 times the actual operating pressure P. b 1.6 is an example of a safety factor S. The safety factor S can be lower or higher, depending on local requirements. Typical safety factors for pressure vessels are 1.3 to 1.7. A person skilled in the art will be able to select an appropriate safety factor.

[0077] The fluid pressure P forces the dispersion containing the liposome precursors to exit the pressure chamber 3 through the filter element 5. Since the filter element 5 is provided with a defined porosity, after a certain number of passes, the size of the liposomes is reduced to the size of the pores. Thus, by selecting a filter element 5 with a given porosity, pressure, and number of passes, the size distribution of the liposomes exiting the filter element 5 can be controlled.

[0078] The extruded dispersion containing the desired liposomes of the desired size is removed from the apparatus 0. It can be used directly as the desired dosage form of the liposomes, or it can undergo further production steps. For example, residual organic solvents may be removed, or the liposomes may be loaded with active ingredients downstream of the liposome extruder. If desired, the liposomes can be isolated from the dispersion.

[0079] Due to clogging, the pores of the filter element 5 will become blocked after a certain period of operation in the liposome extrusion process. As a result, the flow through the filter will continue to decrease and will stop at a certain point. In order to re-establish a dense size distribution, the old filter element 5 must be replaced with a new one.

[0080] To this end, the fluid pressure P is released and the pressure chamber 3 is opened by disengaging the cap 3 b from the socket 3 a and lifting the cap 3 b.

[0081] Disengagement is achieved by opening the bolted connection 7. The bolted connection consists of multiple bolts 7a, each of which is screwed into a respective nut 7b, which is clamped into a U-shaped hook 7c on the cap 3b. Opening the bolted connection 7 is quite simple because each bolt 7a is pivoted about a horizontal axis tangentially pointing to the circumference of the socket 3a. After loosening the nut 7b, the bolt 7a with the nut 7b can be pivoted about the horizontal axis to release the hook 7c. The bolts 7a will not be lost because they are attached to the socket. In addition, the bolts 7a do not need to be lifted, making pivoting easier. Finally, since the nut 7b does not need to be removed from the bolt, the number of turns to tighten or loosen the screw connection is reduced. Removing the entire bolt from the thread requires more turns. In summary, the bolted connection 7 of the device of the present invention can be opened or closed quickly.

[0082] Once the bolt connection 7 is open, the cap 3b can be lifted using the lifting mechanism 6. When the cap 3b is lifted, the filter holder 4 can be removed from the socket 3a by grasping the handle 10. If only one filter holder 4 is available, a new filter element 5 can be inserted into it by replacing the old one. A faster method is to provide two filter holders: the new filter holder can be prepared during the extrusion process. This reduces downtime in the process.

[0083] exist Figure 4 As can be best seen in the top view in the z-direction, the bolts 7a lie on the bolt circle 7d. The axis of the vertical guide slot 2 lies within the bolt circle 7b. This makes all bolts easily accessible from all sides and provides a wider area for removing the filter holder 5 from the socket.

[0084] Figure 5 and Figure 6 Similar to Figure 1 and Figure 3 , but the cap 3b is closed.

[0085] Figure 7 The filter holder 4 is shown in isolation from a top view (x / y plane). The filter element (not shown) is placed in a central receiving portion 11 with a porous, flat support screen 12. Since the filter holder 4 is located inside the pressure chamber, it does not need to withstand high pressure loads. Therefore, it is designed to be lightweight. To facilitate manual movement, the filter holder 4 is equipped with two handles 10. The filter holder 4 is intended for continuous use, while the filter element is replaced when worn.

[0086] from Figure 8 In the cross-sectional view of the filter holder 4 in FIG, the receiving portion 11 of the filter element and the porous flat supporting screen 12 can be easily seen.

[0087] Not shown here is a flat porous drainage element to be placed between the support screen 12 and the filter element 5. The porosity of the drainage element is selected so that the pore diameter of the drainage element is larger than the pore diameter of the filter element 5, but smaller than the pore diameter of the support screen 12. Such a drainage element prevents the filter element 5 from squeezing into the pores of the support screen 12.

[0088] Reference numerals

[0089] x first horizontal axis

[0090] y Secondary horizontal axis

[0091] z vertical axis

[0092] 0 Device / Liposome Extruder

[0093] 1 Framework

[0094] 2 guide grooves

[0095] 2a Guide rail

[0096] 2b Guide sleeve

[0097] 3 Pressure chamber

[0098] 3a socket

[0099] 3b Cap

[0100] 4 Filter holder

[0101] 5 filter element

[0102] 6 Lifting mechanism

[0103] 7 Bolt connection

[0104] 7a Bolt

[0105] 7b Nut

[0106] 7c hook

[0107] 7d bolt circle

[0108] 8 cavities

[0109] 9 Inner surface

[0110] 10 handles

[0111] 11. Undertaking Department

[0112] 12 porous flat support screen

[0113] E Ellipsoid

[0114] a is the length of the semi-axis of the ellipsoid in the x direction

[0115] b is the length of the semi-axis of the ellipsoid in the y direction

[0116] c is the length of the semi-axis of the ellipsoid in the z direction

[0117] P fluid pressure

[0118] P b Internal pressure

[0119] S Safety factor

[0120] D is the diameter of the pores in the filter element

Claims

1. An apparatus (0) for extruding liposomes, comprising the following components: A device for applying a fluid pressure P to a liquid medium, wherein the fluid pressure P is 20*10 5 Pa to 200*10 5 Pa; · A frame (1) including a vertical guide groove (2); A pressure chamber (3) comprising a socket (3a) and a cap (3b) releasably coupled to each other, wherein the socket (3a) is fixed to the frame (1), wherein the cap (3b) is vertically guided by the vertical guide groove (2), wherein the pressure chamber (3) is designed to withstand pressure from a pressure source. b =S*PCalculated internal fluid pressure P b , wherein S is a reasonable safety factor, preferably selected from the range of 1.3 to 1.7, and wherein the cap (3b) comprises an inner surface (9) approximating an ellipsoid (E) defined by the following equation: x 2 / a 2 +y 2 / b 2 +z 2 / c 2 =1 where x, y, and z are Cartesian coordinates, where x and y are horizontally oriented, and z is vertically oriented, where a, b, and c are defined as the lengths of the semi-axes of the ellipsoid (E), and where the pressure chamber (3) is designed such that the lengths a, b, c of the semi-axes of the ellipsoid (E) satisfy the following two conditions: c < a and c < b; where the cap (x) is designed such that the lengths a and b of the semi-axes of the ellipsoid (E) satisfy the condition a = b < 500 mm or a = b < 300 mm; · A filter holder (4) removably mounted in the socket (3a); At least one porous filter element (5) defining the outlet of the pressure chamber (3), wherein the filter element (5) comprises open pores having a diameter D, wherein the pore diameter D is 50*10 -9 m to 50*10 -6 m or 80*10 -9 m to 5*10 -6 m, thereby accommodating the filter element (5) in the filter holder (4).

2. The apparatus (0) according to claim 1, wherein the cap (3b) is designed such that the lengths a and b of the semi-axes of the ellipsoid (E) satisfy the condition a = b.

3. The device (0) according to claim 1 or 2, characterized in that The ellipsoid (E) is convex.

4. The apparatus according to at least one of the preceding claims, wherein the cap (3b) is designed such that the length c of the semi-axis of the ellipsoid (E) satisfies the condition 10 < c < 20 mm.

5. The apparatus (0) according to at least one of the preceding claims, wherein the filter holder (4) consists of a substantially flat support screen (12) and one or more filter elements (5), whereby the flat support screen (12) extends substantially horizontally, and wherein the flat support screen (12) is porous and configured such that a liquid medium can flow through the filter holder (4).

6. The apparatus (0) according to claim 5, wherein the filter holder (4) additionally includes at least one flat porous drainage element located between the support screen (12) and the filter element (5), wherein the pore size of the drainage element is larger than the pore size of the filter element (5), and wherein the pore size of the drainage element is smaller than the pore size of the support screen (12).

7. The apparatus (0) according to at least one of the preceding claims, wherein the filter holder (4) includes at least two handles (10) for grasping to remove the filter holder (4) from the socket (3a).

8. The apparatus (0) according to at least one of the preceding claims, wherein the filter holder (4) is made of a material having a higher magnetic permeability than the material of the socket (3a).

9. Device (0) according to at least one of the preceding claims, characterized in that The filter element (5) is a flat plate made of a porous material selected from polycarbonate, sintered metal, and metal foil, wherein the flat plate is preferably a circular flat plate.

10. The apparatus (0) according to at least one of the preceding claims, wherein the apparatus further includes the following component: a lifting mechanism (6) designed to lift the cap (3b).

11. The apparatus (0) according to claim 10, wherein the lifting mechanism (6) is functionally separated from the guide groove (2).

12. The device (0) according to claim 11, characterized in that The frame (1) comprises one, preferably exactly one, vertically upright beam extending to the outside of the pressure chamber (3), wherein the beam forms a guide rail (2a), and wherein the cap (3b) is equipped with a guide sleeve (2b) which is vertically movable on the guide rail (2a), whereby the guide channel (2) consists of the guide rail (2a) and the guide sleeve (2b).

13. The device (0) according to claim 12, wherein the socket (3a) and the cap (3b) are releasably coupled to each other by a bolt connection (7), wherein the bolt connection (7) comprises a plurality of vertically extending bolts (7a) located on a horizontally arranged bolt distribution circle (7d), characterized in that The effective axis of the vertical guide groove (2) points to the circumference of the bolt distribution circle (7d).

14. The device (0) according to claim 13, characterized in that At least one bolt (7a) is pivotally mounted to the socket (3a), wherein the axis of rotation between the bolt (7a) and the socket (3a) extends horizontally.

15. A method for preparing a target liposome from a liposome precursor, comprising the following steps: a) providing a device (0) for extruding liposomes according to at least one of the preceding claims; b) providing a feed dispersion comprising a liposome precursor dispersed in a liquid dispersion medium; c) applying 20*10 5 Pa to 200*10 5 a hydraulic pressure P of Pa to obtain a pressurized feed dispersion; d) extruding the pressurized feed dispersion through a filter element (5) of an apparatus (0) to obtain an extruded dispersion comprising target liposomes dispersed in a dispersion medium; e) Optional: Recovering the desired liposomes from the extruded dispersion.

16. Method according to claim 15, wherein the method is carried out until a defined degree of clogging of the filter element (5) is reached, characterized in that After reaching a defined degree of clogging, the device (0) is depressurized, the cap (3b) and the socket (3a) are released from one another, the cap (3b) is lifted, the filter holder (4) containing the filter element (5) with reduced permeability is replaced with a new filter holder (4) containing a new filter element (5), the cap (3b) is lowered, the socket (3a) and the cap (3b) are recoupled to one another, the device (0) is repressurized and the method is continued.

17. The method of claim 16, wherein the following steps are performed in 5 minutes or less: The device (0) is depressurized, the cap (3b) and the socket (3a) are released from each other, the cap (3b) is lifted, the filter holder (4) accommodating the filter element (5) with reduced permeability is replaced with a new filter holder (4) accommodating a new filter element (5), the cap (3b) is lowered, the socket (3a) and the cap (3b) are recoupled to each other, and the device (0) is repressurized.

18. The method according to claim 17 or 18, wherein the filter holder (4) is made of a material having a higher magnetic permeability than the material of the socket (3a), characterized in that The filter holder (4) is removed from the socket (3a) by means of a magnetic manipulator.

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