Method for separating solids from plasma-derived solution

Abstract

A method (100) of separating solids from a plasma-derived solution (46) is described. The method (100) includes feeding the solution (46) into the decanter centrifuge (10) at a feed rate. The method (100) further includes centrifuging (104) the solution (46) using the decanter centrifuge (10) to produce a centrifuged liquid (48) having a reduced solids content relative to the solution fed into the decanter centrifuge (10) such that the mass of the centrifuged liquid (48) is at least 75% of the mass of the solution (46) fed into the decanter centrifuge (10).

Description

Technical Field

[0001] The present disclosure generally relates to a method of separating solids from a liquid, and more particularly, the present disclosure relates to a method of separating solids from a solution derived from plasma. Background Art

[0002] The evolving understanding of the functions of plasma proteins and the defects involved in various blood disorders, coupled with improvements in the storage of the major protein components of human blood, has led to an increased utilization of specific subfractions of human blood, particularly the cellular components (red cells, platelets, and white cells) and plasma protein fractions (albumin, fibrinogen, and globulins, including euglobulins, pseudoglobulins, alpha-, beta-, and gamma-globulins, such as immunoglobulin G (IgG)), rather than whole blood, for therapeutic purposes.

[0003] Especially the plasma protein fraction of human blood is of great value to the pharmaceutical industry in the production of therapeutic agents for the treatment of, among other things, fibrinogen, fibrinolytic and coagulation disorders and immunodeficiencies (eg, hemophilia, von Willebrand's disease and fibrinogen deficiency).

[0004] The plasma fraction is formed by a plasma fractionation process, such as the Cohn process, the Kistler and Nitschmann process, or a variation of these processes. These industrial-scale cold ethanol fractionation methods enable the extraction of a variety of plasma proteins from a plasma source. Such a process typically involves thawing frozen plasma (batch size in the range of 1000kg to 15000kg) to form a frozen supernatant and a cryoprecipitate rich in albumin. The cryoprecipitate contains valuable coagulation factors that are subsequently separated from the frozen supernatant. In the Cohn process or the Kistler and Nitschmann process, the frozen supernatant can be optionally exposed to an initial low ethanol (typically 8%) precipitation stage to remove fibrinogen. The precipitate (fraction I) is removed again and can be used to manufacture other products, such as fibrinogen. Also optionally, an adsorption step using ion exchange or affinity resin is performed on any of these two intermediate fractions to extract other proteins (e.g., prothrombin complex; antithrombin III; C1 esterase inhibitor). Subsequently, albumin is extracted from supernatant I by increasing the ethanol concentration to about 25% (Cohn method, pH about 6.9) or about 19% (Kistler and Nitschmann method, pH about 5.85), precipitating the immunoglobulins (fraction (I+) II+III or precipitate A), while albumin remains in solution (supernatant (I+) II+III or filtrate A). Albumin is then separated from most other plasma contaminants (primarily alpha and beta globulins) by further adding ethanol to a final ethanol concentration of about 40% (fraction IV). In the final step, albumin itself is precipitated near its isoelectric point. The precipitated paste (fraction V) can be kept frozen prior to further processing. It is important to recognize that these treatments are somewhat adaptable and have been optimized over the years to suit each manufacturer's product portfolio. For example, is there an additional Cohn fractionation step (fraction IV-1) after the fraction (I+) II+II step that can be used to extract alpha 1 antitrypsin. Another example is to extract hemopexin using fraction IV-4 derived from fraction II+III or fraction (I+)II+III.

[0005] A separation process is required to purify or separate larger solid contaminants from the plasma fraction so that the plasma fraction can be further processed to obtain the desired protein components. Filter presses are usually used to separate solid and liquid phases. The filtration process is carried out in the filter plates of the filter press, wherein several filter plates are connected to each other to form a filter plate assembly. Pressure is applied to the filter plate assembly by means of a closing cylinder (usually a hydraulic closing cylinder) in order to ensure the necessary sealing between the individual filter plates. Each of the filter plates has a filter area covered with a filter medium, wherein the resuspended plasma fraction to be filtered is pressed into a filter chamber formed between two filter plates and abuts against the filter medium. Applying the product to the filter press allows the liquid to pass through the filter medium, while the solids are retained on the filter medium. The filtrate between the filter medium and the filter area is then taken away, and the filter cake is retained in the filter chamber. When the filter plates are separated from each other, the solids forming the filter cake are harvested from the filter press.

[0006] However, the operation of the filter press is labor-intensive and time-consuming. In addition, the filter press has a large footprint, thus requiring a large storage and operation space.

[0007] Any discussion of documents, acts, materials, devices, articles or the like contained in this specification should not be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims. Summary of the invention

[0008] In one aspect of the present disclosure, a method for separating solids from a plasma-derived solution is provided, the method comprising: feeding the solution into a decanter centrifuge at a feed rate; and centrifuging the solution using the decanter centrifuge to produce a centrate having a reduced solids content relative to the solution fed to the decanter centrifuge, wherein the decanter centrifuge comprises: a screw rotating at a screw speed; a bowl rotating at the bowl speed to produce a bowl gravity force, wherein the bowl speed is different from the screw speed, thereby defining a speed differential, the speed differential determining the rate at which a solid phase is conveyed by the screw; and an overflow weir located on an inner surface of the bowl, the size of the overflow weir defining a pool depth, and wherein one or more of the feed rate, the bowl gravity, the speed differential, and the overflow weir size are selected so that the mass of the centrate is at least 75% of the mass of the liquid phase of the solution fed to the decanter centrifuge.

[0009] The solution may include a plasma fraction. The solution may include a buffer. The buffer may include sodium acetate, water for injection, or phosphate. The solution may have an extraction ratio of kilograms of plasma fraction to liters of buffer of about 1:2 to about 1:10.

[0010] The solution may contain hemopexin. The solution may contain albumin. The solution may contain immunoglobulin G. The method may further include adding caprylic acid to the solution or the centrate for delipidation.

[0011] The solution may contain a filter aid. Depending on the size of the drum, the feed rate of the solution may be as high as about 10,000 kilograms per hour. The gravity of the drum may be about 1000 g to about 4000 g. The speed differential may be about 1 rpm to about 200 rpm. The overflow weir size may be selected so that the pool depth is about 1 mm to about 100 mm.

[0012] The quality of the centrifuge can be at least 75% of the quality of the solution fed into the decanter centrifuge. The quality of the centrifuge can be at least 90% or even at least 95% of the quality of the solution fed into the decanter centrifuge. The turbidity of the centrifuge will depend on the solution processed. In some examples, the turbidity of the solution can be less than 400 nephelometric units (NTU), or in some embodiments less than 35NTU. However, it should be understood that in the case where the solution is immunoglobulin G, the turbidity value may be higher when caprylic acid is added.

[0013] The method may further comprise washing the solids during centrifugation.The method may further comprise filtering the centrate.

[0014] Filtering the centrate may include using a depth filter. The depth filter may have a retention rate of 15 microns or finer. The centrate may be produced so that the centrate can be filtered at a flux of at least 15 kg of plasma fraction per square meter of depth filter. The turbidity of the centrate filtered using the depth filter may be less than 150 nephelometric units. The mass of the centrate filtered using the depth filter may be at least 95% of the mass of the centrate. The method may further include adding a filter aid to the centrate before filtering the centrate using the depth filter.

[0015] Filtering the centrate may include using a membrane filter. The membrane filter may be a 1 micron filter or finer filter. Filtering the centrate may include using a combination of a depth filter and a membrane filter. The filtrate may be produced at a throughput of at least 300 liters per square meter of the membrane filter. The turbidity of the filtrate using the membrane filter may be less than 50 NTU. The mass of the filtrate using the membrane filter may be at least 99% of the mass of the solution applied to the membrane filter.

[0016] In another aspect of the present disclosure, a method for separating solids from a plasma-derived solution is provided, the method comprising: feeding the solution into a decanter centrifuge at a feed rate; and centrifuging the solution using the decanter centrifuge to produce a centrate having a reduced solids content relative to the solution fed to the decanter centrifuge, wherein the decanter centrifuge comprises: a screw rotating at a screw speed; a bowl rotating at a bowl speed to produce a bowl gravity, wherein the bowl speed is different from the screw speed to define a speed differential; and an overflow weir located on an inner surface of the bowl, the overflow weir having a size that defines a pool depth.

[0017] In another aspect of the present disclosure, a plasma product produced using any embodiment of the above method is provided.

[0018] Throughout this specification, the word "comprise" or variations such as "including" or "having", will be understood to imply the inclusion of stated elements, integers or steps, or groups of elements, integers or steps, but not the exclusion of any other elements, integers or steps, or groups of elements, integers or steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0020] Figure 1 A schematic cross-sectional view of an embodiment of a decanter centrifuge is shown;

[0021] Figure 2 shows different overflow weir embodiments with a decanter centrifuge Figure 1 A schematic cutaway cross-sectional view of a decanter centrifuge is shown;

[0022] Figure 3 Shows the use of Figure 1 A flow chart of an embodiment of a method of using a decanter centrifuge to separate solids from a plasma-derived solution to produce a centrate;

[0023] Figure 4 Shows Figure 3 A flowchart of another embodiment of the method shown;

[0024] Figure 5 Shows the Figure 3 A line graph showing experimental results of the relationship between turbidity of the centrifuged liquid and flow rate at different drum weights when the method shown is applied to a solution;

[0025] Figure 6 Shows the Figure 3 A line graph showing experimental results of the relationship between turbidity and residence time of a centrifuged liquid at different drum gravities when the method shown is applied to a solution;

[0026] Figure 7 Shows the Figure 3 A line graph showing experimental results of the relationship between liquid recovery rate of centrifuged liquid and flow rate at different drum gravity and speed differences when the method shown is applied to a solution;

[0027] Figure 8 Shows the Figure 3 A line graph showing experimental results of the relationship between centrate turbidity and drum gravity at different feed rates and speed differences when the method shown is applied to a solution;

[0028] Fig. 9 It shows that by Figure 3 A line graph of a particle size distribution analysis of a centrate produced by applying the method shown to a solution;

[0029] Fig.10 Shows the Figure 4 A line graph of experimental results of throughput versus time for different depth filter media and optional filter aids when the method shown is applied to the solution;

[0030] Fig.11 Shows the Figure 4 A bar graph of experimental results of the relationship between throughput and turbidity at different depth filter media and optional filter aids when the method shown is applied to solutions;

[0031] Fig.12 Shows the Figure 4 When the method is applied to solutions Fig.10 and Fig.11 Line graphs of experimental results comparing throughput and flux versus time for a depth filter and filter aid combination to a simulated filter press;

[0032] Fig.13 Shows the Figure 4 When the method is applied to solutions Fig.12 A line graph of experimental results of throughput and flux versus time for a combination of depth filter media and filter aids and a first membrane filter;

[0033] Fig.14 Shows the Figure 4 The method shown is applied to solutions in Fig.12 A line graph of experimental results of throughput and flux versus time for a depth filter media and filter aid combination and a second membrane filter;

[0034] Fig.15 It shows that by Figure 4 Another embodiment of the method shown is applied to a solution Fig.12 a line graph of experimental results of throughput and flux versus time for a combination of depth filter media and filter aids; and

[0035] Fig.16 It shows that by Figure 4 Another embodiment of the method shown is applied to a solution in Fig.12 Line graphs of experimental results showing throughput and flux versus time for various depth filter media and filter aid combinations. DETAILED DESCRIPTION

[0036] General terms

[0037] Throughout the specification, references to individual steps, ingredients of matter, groups of steps, or groups of ingredients of matter shall be deemed to encompass both one and multiple (i.e., one or more) of such steps, ingredients of matter, groups of steps, or groups of ingredients of matter, unless specifically stated otherwise or the context requires otherwise. Thus, as used herein, the singular forms "a," "an," and "the" include plural aspects unless the context clearly dictates otherwise. For example, reference to "a" includes a single as well as two or more; reference to "an" includes a single as well as two or more; reference to "the" includes a single as well as two or more; and so forth.

[0038] Unless otherwise specifically stated, each example of the present disclosure described herein shall apply, mutatis mutandis, to each and every other example. The scope of the present disclosure is not limited by the specific examples described herein, which are intended for illustrative purposes only. Functionally equivalent products, compositions, and methods are clearly within the scope of the disclosure described herein.

[0039] The term "and / or", such as "X and / or Y", should be understood to mean "X and Y" or "X or Y", and should be considered to provide clear support for both meanings or either meaning.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those of ordinary skill in the art to which the invention belongs. Although methods and materials similar or equivalent to the methods and materials described herein can be used for the practice or testing of the present invention, suitable methods and materials are described below. In the event of a conflict, this specification (including definitions) shall prevail. In addition, materials, methods and examples are illustrative only and are not intended to be limiting.

[0041] As used herein, the term "about" means within 5%, more preferably within 1%, of a given value or range. For example, "about 3.7%" means 3.5% to 3.9%, preferably 3.66% to 3.74%. When the term "about" is associated with a numerical range, such as "about X% to Y%, the term "about" is intended to modify both the lower limit (X) and the upper limit (Y) of the range. For example, "about 20% to 40%" is equivalent to "about 20% to about 40%".

[0042] Specific terms

[0043] The term "recovery" or "percent recovery" is used to refer to the mass of the centrate 48 as a percentage of the mass of the solution 46 subjected to centrifugation ( Figure 1 ). Recovery can be used as a performance indicator, wherein the operating parameters of the decanter centrifuge are changed to achieve a minimum recovery. It should be understood that the desired recovery will vary depending on a variety of factors, such as the composition of the feed solution, the intended use of the final product, and whether the centrate will undergo one or more further separation processes (e.g., filtration).

[0044] The term "throughput" is used with respect to filtration processes and is defined as the total volume of centrate filtered per unit filter surface area, expressed as liters of centrate per square meter of filter (L / m2). 2 ), and / or the total mass of plasma fraction per unit filter surface area (kg / m 2 ). It should be understood that any suitable units may be used, such as gallons of centrate per square foot of filter or pounds of plasma fraction per square foot of filter. Throughput may be used as a performance indicator for one or more filtration processes, with higher throughput generally indicating improved recovery, filter performance (e.g., the filter is not clogged or blocked by solids). It should be understood that filter characteristics and operating conditions may be selected to provide a desired throughput.

[0045] The term "flux" is used in connection with filtration processes and is defined as the total volume of centrifuge filtered per unit filter surface area per unit time, expressed in liters of centrifuge per square meter of filter per minute (L / min / m 2 ). Flux can also be defined as the throughput per unit time. It should be appreciated that any suitable unit may be used, for example, gallons of centrifuged liquid per square foot of filter per second. Flux can be used as a performance indicator for one or more filtration processes, with higher fluxes generally indicating improved recovery and filter performance (e.g., the filter is not clogged or blocked by solids). It should be appreciated that filter characteristics and operating conditions may be selected to provide a desired flux.

[0046] Process for separating solids from solutions derived from plasma

[0047] In the drawings, reference numeral 10 generally designates an embodiment of a decanter centrifuge 10 that includes a screw 12 rotating at a screw speed and a bowl 14 rotating at a bowl speed to generate a bowl gravity force ( Figure 1). The bowl speed is different from the screw speed, thereby defining a speed differential, i.e., a rotational speed differential between the screw 12 and the bowl 14, which can be measured in revolutions per minute (rpm). The decanter centrifuge 10 also includes an overflow weir 16 located on the inner surface 18 of the bowl 14, the overflow weir 16 having a dimension that defines a pool depth of the pool 22, which dimension can be measured in millimeters (mm). Figure 2 As shown, weirs 16a, 16b, 16c having different sizes 20a, 20b, 20c may be selected to provide a desired pool depth 22a, 22c.

[0048] The decanter centrifuge 10 comprises a feed pipe 24, blades 26 disposed on an outer surface 28 of the screw 12, a housing 30, a liquid outlet 32 ​​and a solids outlet 34. The bowl 14 comprises a cylindrical section 36 which provides a substantially horizontal surface and thus provides a clarifying zone 38 for the pool 22 in use, and a frustoconical section 40 which provides an angled surface and thus provides a drying or accumulation zone 42 for solids 44 by preventing the pool 22 from reaching the top of the frustoconical section 40 near the solids outlet 34 during use.

[0049] Due to the speed differential between the screw 12 and the bowl 14, the decanter centrifuge 10 is able to separate solids from the solution by gradually gathering the solids 44 by the screw 12 and moving the solids laterally toward the solids outlet 34. The bowl gravity allows the substantially liquid portion of the solution to be disposed proximate to the inner surface 18 of the bowl 14, while the solids 44 are disposed away from the inner surface 18 of the bowl 14 so as to be more easily collected by the blades 26 of the screw 12.

[0050] Those skilled in the art will appreciate that the decanter centrifuge 10 is not limited to this particular embodiment of a decanter centrifuge and may include a variety of different components to function in a substantially similar manner to that described to separate solids.

[0051] Figure 3 An embodiment of a method 100 of separating solids from a plasma-derived solution 46 is shown. The method 100 includes feeding 102 the solution 46 into a decanter centrifuge, such as the decanter centrifuge 10, at a feed rate that can be measured in kilograms per hour; and centrifuging 104 the solution 46 using the decanter centrifuge 10 to produce a centrate 48. The centrate 48 has a reduced solids content relative to the solution 46 fed to the decanter centrifuge 10. In some embodiments, one or more of the feed rate, screw speed, bowl gravity, velocity differential, and overflow weir size 20 are selected so that the mass of the centrate 48 is at least 75% of the mass of the liquid phase of the solution 46 fed to the decanter centrifuge 10.

[0052] Feeding 102 may be performed using a pump (eg, a peristaltic pump). The feed rate of solution 46 into the decanter centrifuge will depend on the size and capacity of the decanter centrifuge. The feed rate of solution may be up to about 10,000 kilograms per hour (kg / h). In some embodiments, the feed rate can be about 0.5 kg / h, about 1 kg / h, about 25 kg / h, about 50 kg / h, about 75 kg / h, about 100 kg / h, about 150 kg / h, about 200 kg / h, about 250 kg / h, about 300 kg / h, about 400 kg / h, about 450 kg / h, about 500 kg / h, about 600 kg / h, about 700 kg / h, about 800 kg / h, about 900 kg / h, about 1,000 kg / h, about 1,250 kg / h, about 1,500 kg / h, about 1,750 kg / h, about 2 The feed rate of the solution may be in the range of about 10,000 kg / h, about 2,250 kg / h, about 2,500 kg / h, about 2,750 kg / h, about 3,000 kg / h, about 3,250 kg / h, about 3,500 kg / h, about 3,750 kg / h, about 4,000 kg / h, about 4,500 kg / h, about 5,000 kg / h, about 5,500 kg / h, about 6,000 kg / h, about 6,500 kg / h, about 7,000 kg / h, about 7,500 kg / h, about 8,000 kg / h, about 9,000 kg / h, or about 10,000 kg / h. The feed rate of the solution may be in the range of about 10,000 kg / h, about 2,250 kg / h, about 2,500 kg / h, about 2,750 kg / h, about 3,000 kg / h, about 3,250 kg / h, about 3,500 kg / h, about 3,750 kg / h, about 4,000 kg / h, about 4,500 kg / h

[0053] The drum gravity can be about 500g, about 600g, about 700g, about 800g, about 900g, about 1000g, about 1250g, about 1500g, about 1750g, about 2000g, about 2250g, about 2500g, about 2750g, about 3000g, about 3250g, about 3500g, about 3750g, about 4000g, about 4500g, about 5000g, about 5500g, about 6000g, about 6500g, about 7000g, about 7500g, about 8000g, about 8500g, about 9000g, about 9500g, or about 10000g. In one embodiment, the drum gravity may be within a range between any two of the above upper and / or lower concentration limits, such as between about 1000 g and about 10000 g, for example, between about 1000 g and about 4000 g.

[0054] The relationship between the bowl weight and the bowl speed is parabolic and is proportional to the radius of the bowl 14 according to the following formula:

[0055] g = 1.118 × 10 -5 ×R×S2

[0056] Where: g is the gravity of the drum,

[0057] R is the drum radius (cm),

[0058] S is the drum speed (rpm).

[0059] In the decanter centrifuge 10, the frustoconical section 40 near the solids outlet 34 of the bowl 14 has a radius of 20 mm (2 cm), and the cylindrical section 36 of the bowl 14 has a radius of 30 mm (3 cm). Therefore, the reported gravity value is the gravity in the cylindrical section 36, because the gravity in the cylindrical section is the maximum gravity within the bowl 14.

[0060] The speed difference between spiral member 12 and drum 14 can be about 1rpm to about 200rpm, for example about 1rpm to about 100rpm.The speed difference can be about 0.5rpm, about 1rpm, about 1.5rpm, about 2rpm, about 2.5rpm, about 5rpm, about 7.5rpm, about 10rpm, about 15rpm, about 20rpm, about 25rpm, about 30rpm, about 35rpm, about 40rpm, about 45rpm, about 50rpm, about 55rpm, about 60rpm, about 65rpm, about 70rpm, about 75rpm, about 80rpm, about 85rpm, about 90rpm, about 95rpm, about 100rpm, about 110rpm, about 120rpm, about 130rpm, about 140rpm, about 150rpm, about 160rpm, about 170rpm, about 180rpm, about 190rpm or about 200rpm.The speed difference can be in the scope between any two values ​​in the above-mentioned values. However, it will be appreciated that in some cases, in the case of larger centrifuges, the speed differential between the screw and the bowl may exceed these values.

[0061] A higher speed differential generally reduces the residence time because the solids 44 are moved toward the solids outlet 34 by the blades 26 of the screw 12 at a faster speed (referred to as the "axial conveying speed"). However, a faster axial conveying speed may result in lower recoveries due to less dewatering of the solids 44 (also referred to as the filter cake (i.e., a wetter filter cake)). Conversely, a slower axial conveying speed may result in extended residence times, higher recoveries due to greater dewatering of the filter cake, and accumulation of solids 44 in the decanter (which may result in plugging and decanter shutdown). It should be understood that the selection of the speed differential will depend on many factors, such as the type and solids content of the feed, the desired properties of the centrate, and a balance between appropriate operating efficiency and appropriate system recovery. The axial conveying speed can be calculated according to the following formula:

[0062]

[0063] Where: v is the axial conveying speed (m / min),

[0064] G is the screw pitch (m),

[0065] N is the differential speed (rpm).

[0066] Overflow weir 16 can have any suitable shape of hole to provide the desired pool depth of pool 22, for example, overflow weir 16 can have a circular, oval or polygonal hole. In some embodiments, overflow weir 16 has a circular hole and has an annular shape. In these embodiments and as Figure 2 As shown, the weir sizes 20a, 20b, 20c are the diameters of the circular apertures such that a larger weir size (e.g., 20c) provides a shallower pool depth (e.g., 22c) and a smaller weir size (e.g., 20a) provides a deeper pool depth (e.g., 22a).

[0067] The overflow weir size 20 is selected so that the pool depth is from about 1 mm to about 100 mm. Figure 2 Three laboratory scale exemplary overflow weirs 16a, 16b, 16c are shown, providing pool depths of 8 mm, 6 mm and 4 mm respectively, as will be discussed in more detail below in the Examples. It will be appreciated that the weir sizes 20a, 20b, 20c may be selected so that the pool depth is about 1 mm, about 1.5 mm, about 2 mm, about 2.5 mm, about 3 mm, about 3.5 mm, about 4 mm, about 4.5 mm, about 5 mm, about 5.5 mm, about 6 mm, about 6.5 mm, about 7 mm, about 7.5 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, about 20 mm, about 22.5 mm, about 25 mm, about 27.5 mm, about 30 mm, about 935 mm, about 40 mm, about 45 mm, about 50 mm, about 55 mm, about 60 mm, about 65 mm, about 70 mm, about 75 mm, about 80 mm, about 90 mm, or about 100 mm. The overflow weir size can be within a range between any two of the above values.

[0068] The pool depth, and therefore the fill volume in the pool 22 (referred to as the "dewatering volume"), is directly proportional to the time that the solution 46 is in the centrifuge 10 before the centrate 48 is produced. This time is referred to as the "residence time" and will be discussed in the example section below. The residence time is governed by an inverse relationship to the feed flow rate of the solution 46 fed into the decanter centrifuge 10 according to the following formula:

[0069]

[0070] Where: R t is the dwell time (seconds),

[0071] V is the dehydrated volume (liters),

[0072] Q f is the feed flow rate (liters per second).

[0073] Method 100 can provide the centrate 48 with at least 75% recovery. In other words, the quality of the centrate 48 can be at least 75% of the quality of the solution 46 fed to the decanter centrifuge 10. In some embodiments, the method can provide the centrate 48 with at least 90% or even at least 95% recovery. Increasing the recovery will provide a drier filter cake, which indicates that the liquid product loss in the filter cake is less. Operation parameters (e.g., feed rate, drum gravity, speed difference, and / or pool depth) and parameters of the solution 46 can be selected to increase the recovery. The recovery can also be increased by further including washing solids 44 during centrifugation by method 100. It will be appreciated that the recovery of the centrate 48 can be at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, 60%, at least about 62.5%, at least about 65%, at least about 67.5%, at least about 70%, at least about 72.5%, at least about 75%, at least about 77.5%, at least about 80%, at least about 82.5%, at least about 85%, at least about 87.5%, at least about 90%, at least about 92.5%, or at least about 95%.

[0074] The method 100 can be performed such that the turbidity of the centrate is less than 400 (NTU). In some embodiments, lower turbidity of the centrate 48 can be a general indicator of higher recovery and increased solid separation of the centrate 48, and thus it is desirable for the centrate 48 to have low turbidity. The operating parameters (e.g., feed rate, bowl gravity, velocity differential, and / or pool depth) and the parameters of the solution 46 can be selected to reduce turbidity. It is understood that the turbidity of the centrate 48 can be less than about 600NTU, less than about 550NTU, less than about 500NTU, less than about 450NTU, less than about 400NTU, less than about 375NTU, less than about 350NTU, less than about 325NTU, less than about 300NTU, less than about 275NTU, less than about 250NTU, less than about 225NTU, less than about 200NTU, less than about 175NTU, less than about 150NTU, less than about 125NTU, less than about 100NTU, less than about 75NTU, less than about 50NTU, less than about 35NTU, less than about 30NTU, or less than about 25NTU. The turbidity of the centrate 48 can be within the range between any two of the above values.

[0075] In some embodiments, solution 46 includes plasma fractions, for example, fractions (I+)II+III containing IgG, fractions IV-4 containing hemopexin, and fraction V containing albumin. Those skilled in the art will appreciate that solution 46 is not limited to the use of plasma fractions, and that plasma fractions are not limited to the aforementioned fractions, but may include any suitable plasma fractions, for example, any plasma fractions described in the background section. Those skilled in the art will also appreciate that solution 46 may be derived from other blood sources, such as animal blood, for example bovine blood.

[0076] The use of different plasma fractions may require the selection of different operating parameters of the decanter centrifuge 10 in order to obtain higher recovery and lower turbidity of the centrate 48. Moreover, certain plasma fractions may provide higher recovery and lower turbidity than other plasma fractions under the same operating parameters. For example, the use of fraction V containing albumin may provide higher recovery and lower turbidity, as seen in the Examples section.

[0077] The temperature of solution 44 can be any suitable temperature for the solution components. In one embodiment, the solution is maintained at a temperature in the range of about 4°C to about 37°C. In some embodiments, the temperature of the solution is less than about 25°C.

[0078] Preferably, the conductivity of the solution is from 2 mS / cm to about 40 mS / cm. For example, the conductivity of the solution can be about 2 mS / cm, 3 mS / cm, 4 mS / cm, 5 mS / cm, 6 mS / cm, 7 mS / cm, 8 mS / cm, 9 mS / cm, 10 mS / cm, 11 mS / cm, 12 mS / cm, 13 mS / cm, 14 mS / cm, 15 mS / cm, 16 mS / cm, 17 mS / cm, 18 mS / cm, 19 mS / cm, 20 mS / cm, 21 mS / cm, 22 mS / cm, 23 mS / cm, 24 mS / cm, 25 mS / cm, 26 mS / cm, 27 mS / cm, 28 mS / cm, 29 mS / cm, 30 mS / cm, 31 mS / cm, 32 mS / cm, 33 mS / cm, 34 mS / cm, 35 mS / cm, 36 mS / cm, 37 mS / cm, 38 mS / cm, 39 mS / cm, 40 mS / cm, 41 mS / cm, 42 mS / cm, 43 mS / cm, 44 mS / cm 1mS / cm, 22mS / cm, 23mS / cm, 24mS / cm, 25mS / cm, 26mS / cm, 27mS / cm, 28mS / cm, 29mS / cm, 30mS / cm, 31mS / cm, 32mS / cm, 33mS / cm, 34mS / cm, 35mS / cm, 36mS / cm, 37mS / cm, 38mS / cm, 39mS / cm or 40mS / cm. Although the conductivity of the solution is typically measured at room temperature, it should be understood that the conductivity can also be measured at a given temperature of the solution fed to the decanter centrifuge. In one embodiment, the solution can have a conductivity of about 8mS / cm to about 15mS / cm when measured at room temperature.

[0079] Solution 46 may also include a buffer. In these embodiments, a buffer is added to the plasma-derived product to form solution 46 before the buffer is fed to the decanter centrifuge. The purpose of the buffer is to resuspend the plasma fraction, which is the precipitate and may be in the form of a paste, so that solution 46 has a suitable viscosity to be fed into decanter centrifuge 10. Any suitable buffer may be used, for example, the buffer may include sodium acetate, water (e.g., water for injection (WFI)), or phosphate (e.g., disodium phosphate).

[0080] The conductivity of the solution can be adjusted as needed to achieve the desired conductivity. Where the solution comprises a buffer solution, the concentration of the buffer can be adjusted to achieve the desired conductivity without significantly diluting the sample.

[0081] The ratio of the plasma fraction to the buffer used in solution 46 can affect the recovery and / or turbidity of the centrate. This ratio is called the extraction ratio of solution 46 and is defined by the number of kilograms of plasma fraction and the number of liters of buffer. It should be understood that the extraction ratio can vary depending on the plasma fraction used and practical considerations (e.g., the space required for storing and using the volume of buffer solution required for a higher extraction ratio). For example, an extraction ratio of 1:1 or higher can be used, but in order to obtain a higher recovery, an extraction ratio of at least 1:2 will be appropriate. The actual maximum extraction ratio will be 1:20, but it will be understood by those skilled in the art that if a specific recovery rate and / or resuspending a specific plasma fraction is required, the extraction ratio can exceed 1:20.

[0082] Taking these factors into consideration, solution 46 can have an extraction ratio of about 1:2 to about 1:10. However, the extraction ratio can be any suitable extraction ratio, for example, the extraction ratio can be about 1:1, about 1:1.5, about 1:2, about 1:2.5, about 1:3, about 1:3.5, about 1:4, about 1:4.5, about 1:5, about 1:5.5, about 1:6, about 1:6.5, about 1:7, about 1:7.5, about 1:8, about 1:8.5, about 1:9, about 1:9.5, about 1:10, about 1:11 0.5, about 1:11, about 1:11.5, about 1:12, about 1:12.5, about 1:13, about 1:13.5, about 1:14, about 1:14.5, about 1:15, about 1:15.5, about 1:16, about 1:16.5, about 1:17, about 1:17.5, about 1:18, about 1:18.5, about 1:19, about 1:19.5, about 1:20, or about 1:20.5.

[0083] In some embodiments, solution 46 includes a filter aid. In these embodiments, the plasma fraction is a precipitate and may be in the form of a paste, and the plasma fraction includes a filter aid. The filter aid may be any suitable filter aid, for example, the filter aid may be cellulose-based or silica-based.

[0084] In some embodiments, such as embodiments where solution 46 includes IgG, method 100 further includes adding caprylic acid to solution 46 to defatted solution 46. In other embodiments, caprylic acid is added to centrate 48 to defatted centrate 48. Where caprylic acid is used, calcium phosphate may be added to solution 46 or to centrate 48 to neutralize any excess caprylic acid.

[0085] For example Figure 3As shown, method 100 may further include filtering 106 the centrate 48. In some embodiments, filtering 106 includes filtering the centrate 48 using a depth filter (not shown). Filtering 106 may further include adding a filter aid to the centrate 48 before filtering the centrate 48 using the depth filter. The filter aid may also be used alternatively or additionally to pre-coat the depth filter. The depth filter may have a retention rate of 15 microns or finer, for example, a retention rate between 6 microns and 15 microns, between 3 microns and 6 microns, between 1 micron and 3 microns, or between 0.4 microns and 0.8 microns. It should be understood that the retention rate refers to the pore size of the depth filter, and the upper limit of the retention rate range represents a larger pore size near the outlet of the depth filter, and the lower limit of the range represents a smaller pore size near the outlet of the depth filter.

[0086] In some embodiments, filtering 106 includes filtering centrate 48 using a membrane filter (not shown). The membrane filter is a 1 micron filter or finer filter, for example, a 1 micron filter, a 0.5 micron filter, a 0.22 micron filter, or a 0.2 micron filter.

[0087] A combination of a depth filter and a membrane filter can also be used to filter the centrate 48, preferably using a depth filter to filter the centrate 48, and then using a membrane filter to filter the filtered centrate. It will be appreciated by those skilled in the art that other filter media and techniques may be used as alternatives or additions to the depth filter and / or membrane filter. It will also be appreciated that the centrate 48 or the centrate filtered using the depth filter and / or membrane filter constitutes the plasma product produced using the method 100.

[0088] Where filtration 106 is included in method 100, in addition to operating parameters of decanter centrifuge 10 (e.g., feed rate, bowl gravity, velocity differential, and / or pool depth) and parameters of solution 46, characteristics and operation of the filter, e.g., filter type, filter pore size, and / or retention rate, may be selected to achieve a desired recovery of filtered centrate.

[0089] The recovery of the centrate 48 may be determined after filtering 106 with the depth filter. That is, the recovery is defined as the mass of the filtered centrate as a percentage of the mass of the solution 46 fed to the decanter centrifuge 10. In embodiments where the filtering 106 includes one or more filtration treatments, the recovery of the filtered centrate after any of the filtration treatments may be at least 60%, e.g., at least 75%, at least 90%, at least 95%. In some examples, the recovery rate of the filtered centrate can be at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, 60%, at least about 62.5%, at least about 65%, at least about 67.5%, at least about 70%, at least about 72.5%, at least about 75%, at least about 77.5%, at least about 80%, at least about 82.5%, at least about 85%, at least about 87.5%, at least about 90%, at least about 92.5%, or at least about 95%.

[0090] In the case where method 100 includes filtering 106, in addition to the operating parameters (e.g., feed rate, drum gravity, velocity difference and / or pond depth) of decanter centrifuge 10 and the parameters of solution 46, the characteristic and operation of the filter can also be selected, e.g., filter type and / or retention rate, to achieve the desired turbidity of the centrate filtered. The turbidity of the centrate filtered can be evaluated after one or more filtering stages. Operating parameters (e.g., feed rate, drum gravity, velocity difference and / or pond depth), parameters of solution 46 and filter type and / or retention rate can be selected to reduce turbidity.

[0091] For example, the turbidity of the centrate filtered using one or more filters can be less than about 600 NTU, less than about 550 NTU, less than about 500 NTU, less than about 450 NTU, less than about 400 NTU, less than about 375 NTU, less than about 350 NTU, less than about 325 NTU, less than about 300 NTU, less than about 275 NTU, less than about 250 NTU, less than about 225 NTU, less than about 200 NTU, less than about 175 NTU, less than about 150 NTU, less than about 125 NTU, less than about 100 NTU, less than about 75 NTU, less than about 50 NTU, less than 35 NTU, less than 30 NTU, or less than about 25 NTU.

[0092] In some embodiments, centrate 48 is produced such that centrate 48 can be stored at a rate of at least 100 liters of centrate per square meter of one or more filters (L / m 2) throughput. Operational parameters, such as feed rate, drum gravity, velocity differential and / or pool depth, parameters of solution 46, and filter type, filter pore size and / or retention rate can be selected to achieve a desired throughput. For example, centrate 48 can be capable of being filtered in one or more filtration stages at a throughput of at least about 25 L / m 2 , at least about 50L / m 2 , at least about 75L / m 2 , at least about 100L / m 2 , at least about 125L / m 2 , at least about 150L / m 2 , at least about 175L / m 2 , at least about 200L / m 2 , at least about 225L / m 2 , at least about 250L / m 2 , at least about 275L / m 2 , at least about 300L / m 2 , at least about 325L / m 2 , at least about 350L / m 2 , at least about 375L / m 2 , or at least about 400L / m 2 , at least about 450L / m 2 , at least about 500L / m 2 , or at least about 600L / m 2 , or at least about 700L / m 2 , or at least about 800L / m 2 , or at least about 900L / m 2 , or at least about 1000L / m 2 , or at least about 1100L / m 2 , or at least about 1200L / m 2 , or at least about 1300L / m 2 The centrate 48 may be capable of being filtered in one or more filtration stages at a throughput within a range between any two of the above values. It will be appreciated that the throughput may be scaled by adding additional filter units.

[0093] Advantageously, a decanter centrifuge is used in method 100 to separate solids from solution 46 to a degree comparable to prior art techniques such as filter presses, while providing a reduced footprint and a faster overall process. It should be appreciated that the operation of a decanter centrifuge is also less labor intensive than a filter press, and does not require emptying and replacing individual filter plates, which would increase the overall processing time.

[0094] In some embodiments, the use of a decanter centrifuge 10 in method 100 provides a recovery rate of at least 75%, thereby providing a recovery rate comparable to that of using a filter press. In embodiments of method 100 that include filtering the centrate 48, the filter used provides a recovery rate of at least 100 L / m 2 The throughput is comparable to that of a filter press, thus demonstrating that embodiments of method 100 including filtering 106 can be as efficient and rapid as filtering using a filter press while providing the advantages of reduced floor space and labor as described above.

[0095] Those skilled in the art will appreciate that several changes and / or modifications may be made to the above-described embodiments without departing from the broad overall scope of the present disclosure. Therefore, the present embodiments are to be considered in all aspects as illustrative and not restrictive.

[0096] Example

[0097] The following examples should be understood to be illustrative only. Therefore, the following examples should not be interpreted as limiting the embodiments of the present disclosure in any way.

[0098] Figure 5-16 Results of experiments conducted with respect to various embodiments of the method 100 of separating solids from the solution 46 are shown.

[0099] Example 1 – Effects of changing operating parameters such as feed flow rate, bowl gravity, velocity differential and overflow weir size

[0100] Figure 2 A schematic diagram is shown comparing three annular weirs 16a, 16b, 16c having different weir sizes 20a, 20b, 20c, which in this embodiment is the inner diameter of the weir. Figure 2 Also shown in the figure are indications of the pool depths 22a and 22c corresponding to the dimensions 20a and 20c, respectively, and how different pool depths affect the lengths of the clarifying zones 38a, 38c and the drying zones 42a, 42c. In this example, the inner diameters of the three annular overflow weirs 16a, 16b, 16c are 44mm, 48mm, and 52mm, respectively, which define pool depths 22 of 8mm, 6mm, and 4mm, respectively.

[0101] The experiments conducted show that the lower pool depth due to the increased overflow weir inner diameter provides a shorter clarifying zone 38 and a larger drying zone 42, resulting in a smaller filling volume and a shorter residence time. This results in a lower centrate clarity. In contrast, the higher pool depth due to the reduced overflow weir inner diameter provides a longer clarifying zone 38 and a shorter drying zone 42, resulting in a larger filling volume and a longer residence time. This results in higher centrate clarity, and similar recoveries compared to lower pool depths, which is why the following examples prefer a higher pool depth of 8 mm.

[0102] Figure 5 A graph showing the relationship between centrate turbidity and feed flow rate at different drum gravity, where the extraction ratio of the hemopexin extract (fraction IV-4) is 1:2.5 (3 kg of fraction IV-4:7.5 L of 40 mM sodium phosphate buffer), the speed difference is as low as possible (10 rpm, 15 rpm, 20 rpm or 30 rpm, depending on other operating parameters), and the pool depth is 8 mm. By converting the feed flow rate to residence time, Figure 5 The experimental results show that Figure 6 When the feed flow rate increases from 5kg / h to 15kg / h, the residence time decreases from 138 seconds to 46 seconds. Figure 5 and Figure 6 The graphs shown indicate that, regardless of the bowl gravity, in most cases the centrate turbidity increases with increasing feed flow rate.

[0103] Figure 7 A graph showing the recovery versus feed flow rate for different combinations of drum gravity and speed differentials for a hemopexin extract with an extraction ratio of 1:2.5 and a pool depth of 8 mm. Figure 7 The graph shown indicates that the centrate liquid recovery is negatively correlated with the velocity differential and positively correlated with the bowl gravity.

[0104] Figure 8 A graph showing the relationship between centrate turbidity and drum gravity for different combinations of feed flow rate and speed difference is shown, where the extraction ratio of the hemoglobin binding protein extract (Fraction IV-4) is 1:2.5 (3 kg of Fraction IV-4:7.5 L of 40 mM disodium phosphate buffer) and the pool depth is 8 mm. Figure 8 The graph shown indicates that turbidity tends to decrease as the bowl speed increases, with higher differential speeds generally resulting in higher centrate turbidity.

[0105] In this experiment, it was found that increasing the drum gravity to 1500 g or above resulted in a large amount of foaming in the centrate 48, which is generally undesirable. It should be understood that the foaming was produced under the specific conditions of this experiment (including the composition of the solution 46 and the decanter design), and this undesirable result does not preclude the use of higher drum gravity in the method 100.

[0106] Experiments of method 100 were performed using an optimized combination of operating parameters, wherein the extraction ratio of the hemoglobin binding protein extract (Fraction IV-4) was 1:2.5 (3 kg of Fraction IV-4:7.5 L of 40 mM disodium phosphate buffer), which produced a centrate 48 with a recovery of 76% as measured by high performance liquid chromatography (HPLC).

[0107] Example 2 – Particle Size Distribution in Centrate

[0108] Fig. 9 Particle size distribution analysis using dynamic light scattering of the centrate 48 produced from an experiment in which the hemopexin extract (Fraction IV-4) had an extraction ratio of 1:2.5 (3 kg of Fraction IV-4:7.5 L of 40 mM disodium phosphate buffer), a drum gravity of 1000 g, a pool depth of 8 mm, a velocity difference of 10 rpm, and a feed flow rate of 5 kg / h is shown. Fig. 9 The distribution shown indicates that in this experiment, the decanter centrifuge 10 separated the majority of particles from the solution 46 larger than 0.23 microns, and the remaining particles larger than 0.23 microns were degraded filter aids, which in this example were C300B.

[0109] Example 3 – Comparison of the performance of depth filters with and without filter aids

[0110] Fig.10 A throughput versus time graph is shown to compare the use of different depth filter media with and without filter aids to filter centrate 48. In this experiment, centrate 48 was produced from a hemopexin extract (Fraction IV-4) using a decanter centrifuge 10 at an extraction ratio of 1:2.5 (3 kg of Fraction IV-4:7.5 L of 40 mM disodium phosphate buffer), with a drum gravity of 1000 g, a pool depth of 8 mm, a speed differential of 10 rpm, and a feed rate of 5 kg / h. The centrate 48 was filtered for a period of time using each depth filter / depth filter and filter aid combination until the pressure limit had been reached. Fig.10 The graph shown also includes a minimum feasible throughput threshold of 80 L / m selected by the applicant. 2 , and as shown in the figure, K700P depth filter media, K200 Depth Filter Media, Pre-Coated 102 filter aid K200P Depth Filter Media, Pre-coated 150 filter aid K200P Depth Filter Media, and Pre-Coat 150 filter aid K100P depth filter media all exceed this minimum viable throughput threshold.

[0111] Fig.11 Another comparison is shown from Fig.10 The experimental results shown are bar graphs of the turbidity of the resulting filtrate. Fig.11 The diagram shows Fig.10 The minimum feasible throughput threshold in the figure also includes the maximum feasible turbidity threshold of 150NTU selected by the applicant. K100P Depth Filter Media and The combination of 150 filter aids (K100P+D150) was the only combination that met both the minimum feasible throughput threshold and the maximum feasible turbidity threshold and was therefore selected for further experiments.

[0112] Example 4 – Comparing the Throughput of a Decanter Centrifuge to a Filter Press After Depth Filtration

[0113] Fig.12 A graph of throughput and flux versus time is shown to compare K100P+D150 with pre-coated 1000 Results for the 90SP filter, the latter being designed to simulate the use of a filter press to filter solids from a plasma-derived solution 46. For K100P+D150, solution 46 was a hemopexin extract (Fraction IV-4) with an extraction ratio of 1:5 (1.5 kg of Fraction IV-4:7.5 L of phosphate buffer), and the decanter centrifuge 10 had a bowl gravity of 1000 g, a pool depth of 8 mm, a speed difference of 5 rpm, and a feed rate of 5 kg / h. In this experiment, the extraction ratio was increased to 1:5, which resulted in an 85% recovery as determined by HPLC, compared to the 76% yield observed in the previous example using a 1:2.5 extraction ratio. Using the pre-coated 1000 The hemopexin extract (fraction IV-4) at an extraction ratio of 1:2.5 (3 kg of fraction IV-4:7.5 L of 40 mM disodium phosphate buffer) was filtered through a 90SP filter.

[0114] The throughput of K100P+D150 is higher than the throughput of the simulated filter press and exceeds the 23.2 kg plasma fraction sediment per square meter of filter selected by the applicant (kg / m 2 ) target throughput value. This target is based on the expected throughput of 9.08kg / m 2 And the total filter area is 51m 2 The actual filter pressure is calculated, while the total filter area of ​​K100P+D150 is only 20m 2 , so the actual filter press throughput increased by 2.5 times. After about 7.5 minutes, the flux of K100P+D150 did drop to 8L / min / m 2 However, this flux is still higher than the 6.25L / min / m 2 The expected flux.

[0115] Example 5 – Comparison of membrane filter throughput after depth filtration between decanter centrifuge and filter press routes

[0116] Fig.13 and Fig.14 The results of the subsequent filtration of the filtrate of K100P+D150 using a membrane filter are shown. The centrate 48 filtered using K100P+D150 has a hemopexin extract (Fraction IV-4) with an extraction ratio of 1:5 (1.5 kg of Fraction IV-4:7.5 L of phosphate buffer), and the bowl gravity of the decanter centrifuge 10 is 1000 g, the pool depth is 8 mm, the speed difference is 5 rpm, and the feed rate is 5 kg / h. In this experiment, the extraction ratio was increased to 1:5, which resulted in a recovery of 85% as determined by HPLC, compared to the yield of 76% observed when using a 1:2.5 extraction ratio in the previous example.

[0117] Fig.13 Shows the use of 20 Plot of throughput and flux versus time for a 0.22 micron filter compared to the expected 303 L / m using the same membrane filter to subsequently filter the filter press filtrate 2 Throughput also remains roughly constant throughout the filtration process.

[0118] Fig.14 Shows the use of Throughput and flux vs. time for a 0.5 / 0.2 micron filter, with a throughput of 480 L / m 2 , exceeding the use 20 0.22 micron filters to filter the expected 303L / m of filter filtrate 2 The throughput also remained roughly constant throughout the filtration process.

[0119] Example 6 - Effect of increasing the extraction ratio

[0120] Fig.15 A graph showing the throughput and flux versus time for filtering a centrate 48 produced from a hemopexin extract (Fraction IV-4) having an extraction ratio of 1:10 (0.5 kg of Fraction IV-4: 5 L of phosphate buffer) using K100P+D150, and a decanter centrifuge 10 having a bowl weight of 1000 g, a pool depth of 8 mm, a speed differential of 5 rpm, and a feed rate of 5 kg / h. Fig.12 The results shown are similar, with a throughput of over 23.2 kg / m 2 target throughput value, in addition, this increased extraction ratio allows Fig.14 The experimental results showed a more stable flux, and no flux decay over time was observed.

[0121] The recovery of centrate 48 was 90% and the recovery of K100P+D150 filtrate was 95% as measured by HPLC, which resulted in a total recovery of 85% for centrifugation and filtration. The turbidity of centrate 48 was 390 NTU and the turbidity of the filtrate after K100P+D150 was 56.9 NTU.

[0122] Example 7 - Application of the method to a solution containing IgG

[0123] Method 100 was performed on an IgG extract (fraction I+II+III) with an extraction ratio of 1:4.5 (0.9 kg of fraction I+II+III:4.05 L of 0.22 M sodium acetate buffer) and incubated at room temperature for 7 hours once solution 46 reached 20° C. The decanter centrifuge 10 had a bowl gravity of 1000 g, a pool depth of 8 mm, a speed difference of 2 rpm, and a feed rate of 5 kg / h.

[0124] Prior to centrifugation 104, a degreasing agent was added to solution 46, in this example, 83 g of octanoic acid was added over 40 minutes, and solution 46 was incubated for 6 hours at room temperature. Thereafter, 24.7 g of calcium phosphate was added to solution 46 to neutralize any excess octanoic acid prior to decanting, and solution 46 was incubated for an additional 75 minutes at room temperature.

[0125] The recovery of the centrate 48 after centrifugation 104 was 77% and the centrate turbidity was 1611 NTU using spectrophotometric quantification at 280 nm. The reason for the lower recovery was the high moisture content in the filter cake. The filter cake was observed to be very sticky, which was most likely due to the influence of octanoic acid. Under the conditions of this experiment, in-situ washing during centrifugation 104 or increasing the extraction ratio could improve the recovery.

[0126] Fig.16 A graph of throughput and flux versus time is shown for a centrate 48 produced by filtration of an IgG extract with an extraction ratio of 1:4.5 (0.9 kg of fractions I+II+III: 4.05 L of 0.22 M sodium acetate buffer) using K100P+D150 and incubation at room temperature for 7 hours once the solution 46 reached 20°C. The bowl gravity of the decanter centrifuge 10 was 1000 g, the pool depth was 8 mm, the speed difference was 2 rpm, and the feed rate was 5 kg / h. A throughput of 64 L / m was achieved. 2 , which is equivalent to 0.069m 2 / kg plasma fraction (fraction I+II+III), exceeding the expected result of using a filter press for the same plasma fraction by 0.1 m 2 / kg.

[0127] In a further experiment, the centrate 48 was defatted after centrifugation 104, rather than defatting the solution 46 before centrifugation 104. A defatting agent was added to the centrate 48, in this example, 68.9 g of octanoic acid was added over 40 minutes, and the centrate 48 was incubated at room temperature for 400 minutes. Thereafter, 20.7 g of calcium phosphate was added to the centrate 48 to neutralize any excess octanoic acid before filtration, and the centrate 48 was incubated at room temperature for an additional 75 minutes.

[0128] Due to the lower amount of precipitate in solution 46, this experiment increased the recovery yield from the decanter centrifuge to 85% compared to the 77% achieved in the previous experiment. However, after the addition of caprylic acid, a large amount of lipids precipitated out. Therefore, there should be another centrifugation or filtration step to remove all lipids, which will result in a decrease in the overall yield.

[0129] In these experiments, it was found that increasing the drum gravity to 1500 g or above resulted in a large amount of foaming in the centrate 48, which is generally undesirable. It should be understood that the foaming was produced under the specific conditions of this experiment (including the composition of the solution 46 and the decanter design), and this undesirable result does not preclude the use of higher drum gravity in the method 100.

[0130] Example 8 - Application of the method to a solution containing albumin

[0131] The method 100 was performed on an albumin extract (Fraction V) with an extraction ratio of 1:2 (1.6667 kg of Fraction V: 3.3333 L of 0.01 M sodium acetate buffer) and incubated at room temperature for 2 hours. The decanter centrifuge 10 had a bowl gravity of 1000 g, a pool depth of 8 mm, a speed difference of 1 rpm, and a feed rate of 5 kg / h.

[0132] The recovery was 97% with a turbidity of 33.6 NTU as measured by the turbidimeter, which provided a very dry filter cake indicating little liquid product loss in the filter cake. These results indicate that for these parameters, the decanter centrifuge 10 alone will provide the same or even higher recovery than using a filter press when separating solids from a solution 46 containing albumin.

Claims

1. A method for separating solids from a solution derived from plasma, the method comprising: feeding the solution into a decanter centrifuge at a feed rate; and The solution is centrifuged using the decanter centrifuge to produce a centrate having a reduced solids content relative to the solution fed to the decanter centrifuge, wherein the decanter centrifuge comprises: A screw rotating at a screw speed, a drum that rotates at a drum speed to generate a drum weight force, wherein the drum speed is different from the screw speed to define a speed differential, and an overflow weir located on the inner surface of the drum, the overflow weir having an overflow weir size that defines the pool depth, and wherein one or more of the feed rate, the screw speed, the bowl gravity, the velocity differential and the overflow weir size are selected so that the mass of the centrate is at least 75% of the mass of the liquid phase of the solution fed to the decanter centrifuge.

2. The method according to claim 1, wherein: The solution includes a plasma fraction.

3. The method according to claim 2, wherein: The solution includes a buffer.

4. The method according to claim 3, wherein: The buffer includes sodium acetate, water for injection, or phosphate.

5. The method according to claim 3 or claim 4, wherein: The solution has an extraction ratio of kilograms of plasma fraction to liters of buffer of about 1:2 to about 1:

10.

6. A method according to any one of the preceding claims, wherein: The solution includes hemopexin.

7. The method according to any one of claims 1 to 5, wherein: The solution includes albumin.

8. The method according to any one of claims 1 to 5, wherein: The solution includes immunoglobulin G.

9. The method according to claim 8, further comprising adding caprylic acid to the solution or the centrate for degreasing.

10. A method according to any one of the preceding claims, wherein: The solution includes a filter aid.

11. A method according to any one of the preceding claims, wherein: The feed rate of the solution does not exceed 10,000 kilograms per hour.

12. A method according to any one of the preceding claims, wherein: The drum weight is about 1000 g to about 4000 g.

13. A method according to any one of the preceding claims, wherein: The speed difference is from about 1 rpm to about 200 rpm.

14. A method according to any one of the preceding claims, wherein: The overflow weir size is selected so that the pool depth is from about 1 mm to about 100 mm.

15. A method according to any one of the preceding claims, wherein: The mass of the centrate is at least 75% of the mass of the solution fed to the decanter centrifuge.

16. A method according to any one of the preceding claims, wherein: The mass of the centrate is at least 95% of the mass of the solution fed to the decanter centrifuge.

17. A method according to any one of the preceding claims, wherein: The turbidity of the centrate is less than 400 nephelometric turbidity units (NTU).

18. The method of any preceding claim, further comprising washing the solid during centrifugation.

19. The method of any preceding claim, further comprising filtering the centrate.

20. The method according to claim 19, wherein: Filtering the centrate includes using a depth filter.

21. The method according to claim 20, wherein: The depth filter has a retention rate of 15 microns or finer.

22. The method of claim 20 or claim 21, wherein: The centrate is produced so that the centrate can be filtered at a throughput of at least 100 liters of centrate per square meter of the depth filter.

23. The method according to any one of claims 20 to 22, wherein: The turbidity of the centrate filtered by the depth filter is less than 150 NTU.

24. The method according to any one of claims 20 to 23, wherein: The mass of the centrate filtered using the depth filter is at least 75% of the mass of the centrate.

25. The method according to any one of claims 20 to 24, wherein: The mass of the centrate filtered using the depth filter is at least 95% of the mass of the centrate.

26. The method of any one of claims 20-25, further comprising adding a filter aid to the centrate or pre-coating the depth filter before filtering the centrate using the depth filter.

27. The method according to any one of claims 19 to 26, wherein: Filtering the centrate includes using a membrane filter or a combination of a depth filter and a membrane filter.

28. The method according to claim 27, wherein: The membrane filter is a 1 micron or finer filter.

29. A method according to claim 27 or claim 28, wherein: The filtrate is produced at a throughput of at least 300 liters per square meter of the membrane filter.

30. The method according to any one of claims 27 to 29, wherein: The turbidity of the centrifugal liquid filtered by the membrane filter is less than 50 NTU.

31. The method according to any one of claims 27 to 30, wherein: The mass of the centrate filtered using the membrane filter is at least 75% of the mass of the solution fed to the decanter centrifuge.

32. The method according to any one of claims 27 to 31, wherein: The mass of the filtrate filtered using the membrane filter is at least 99% of the mass of the solution applied to the membrane filter.

33. A method according to any one of the preceding claims, wherein: The solution has a conductivity of about 2 mS / cm to about 40 mS / cm.

34. A method according to any one of the preceding claims, wherein: The solution has a conductivity of about 8 mS / cm to about 15 mS / cm.

35. A method according to any one of the preceding claims, wherein: The solution is at a temperature of about 4°C to about 37°C.

36. A method of separating solids from a solution derived from plasma, the method comprising: feeding the solution into a decanter centrifuge at a feed rate; and The solution is centrifuged using the decanter centrifuge to produce a centrate having a reduced solids content relative to the solution fed to the decanter centrifuge, wherein the decanter centrifuge comprises: A screw rotating at a screw speed, a drum that rotates at a drum speed to generate a drum weight force, wherein the drum speed is different from the screw speed to define a speed differential, and An overflow weir is located on the inner surface of the drum, the overflow weir having an overflow weir size that defines a pool depth.

37. A plasma product produced using the method according to any one of the preceding claims.

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