This invention relates to a chromatography apparatus and more particularly to a modular chromatography apparatus wherein a plurality of chromatography modules can be connected to each other to enable linear scaling of a chromatographic process in either a parallel or series flow format.
Process chromatography presently is utilized in many applications including biochemical, clinical, environmental, food and petroleum chemistry. In a chromatographic process, a mixture of components in a fluid is typically resolved in a chromatographic medium (heretofore referred to as the resin or media) having an active adsorptive function. The resolution could also be based on the hydro dynamical size of the components as in Size Exclusion Chromatography. The chromatographic apparatus wherein this separation occurs usually takes the form of a cylindrical column.
In chromatography, scalability from a relatively small capacity process to a relatively large capacity process while attaining essentially the same results is not straightforward. One of the reasons for the difficulty of scaling up the capacity of the chromatographic apparatus is that the wall effect does not scale linearly with column size. It is larger in small diameter columns (<10-20 cm) as compared to large diameter columns. The wall-effect refers to the frictional forces at the walls of the column. These forces allow higher flow rates at a given pressure drop. However, these forces are relevant only in the immediate vicinity of the column wall. In the case of small columns (<10 cm), the contribution of these forces is significant as the area in which they are relevant may be a significant proportion of the total cross-sectional area and help offset some of the hydraulic drag forces. As the column size increases, the relative contribution of these forces is lowered in a nonlinear fashion. In addition, the relative contribution of these forces is dependent on the type of media being packed. The wall effect affects the fluid flow near the wall, resulting in nonhomogenous flow profile and, in addition, it provides additional mechanical support to the chromatographic resin allowing higher linear velocities for the same pressure drop.
A second problem is that as the column size increases, the effect of flow distributor design on the achievement of a homogeneous flow profile in the packed bed becomes more and more pronounced. This effect does not scale linearly with column size.
A third problem is that the bed depth in chromatography processes is typically maintained constant on scale-up. This is mainly due to the hydraulic limitations of the chromatography resin/media. Thus, on scale-up, the aspect ratio (column length/column diameter) diminishes. This also adversely impacts the linearity of scale-up.
A fourth problem is that the chromatographic load (volume or mass) cannot easily be matched with the corresponding required resin volume. Currently, chromatographic columns are offered at discrete sizes. Given the typical lead times for chromatography columns (3-6 months), decisions on column sizes have to be made based on an estimate of the manufacturing capacity. This reduces the flexibility to increase or decrease the media volume as drug demand or plant schedule changes.
Finally, packing the chromatographic media in a column is labor intensive. This scales nonlinearly with scale. At manufacturing scale, the auxiliary equipment required to assist in column packing (media tank, slurry transfer system, column hydraulics, etc) present significant capital investment and manufacturing space footprint.
Accordingly, it would be desirable to provide a chromatographic apparatus which is easily and accurately scaleable. In addition, it would be desirable to provide such an apparatus having a wide range of available volumes of chromatographic media/resin. In addition, it would be desirable to provide such an apparatus wherein scaling up of the chromatographic apparatus, as desired, is not labor intensive. Such an apparatus would provide flexibility as to the chromatographic capacity as well as providing accuracy of results when scaling up.
The present invention provides a chromatographic apparatus which is formed from one or a plurality of identical modules which can be joined together to effect fluid flow into the modules, fluid flow through a chromatographic packed bed of particles within the modules and fluid flow out from the modules. The modules comprise a housing having one or moremore fluid inlets and a fluid outlet and optionally, a vent. The inlet and outlet can be connected respectively to the inlet of one or more such modules and to the outlet of the one or more such modules so that the modules can operate in parallel or in series. Each module contains a chromatographic packed bed of particles of substantially the same volume.
Scalability is achieved by joining the number of modules desired to obtain the desired effective volume of chromatographic packed bed. Since the modules have identical size and shape, the wall effect within each module is the same as the wall effects within the remaining modules. This provides the advantage of rendering scalability linear. In addition, the use of these modules permits the use of a wide range of effective volumes of chromatographic media. This provides the advantage of providing optimum operation for a wide variety of chromatographic processes. In addition, the present invention enables disposable resin-based chromatographic operation. The chromatographic modules preferably are operated in parallel flow. Serial flow also can be effected.
The chromatographic apparatus provides flexibility in meeting the needs of a wide variety of chromatography processes in that the effective chromatographic bed volume can be easily tailored to a specific chromatographic process. All that one needs to do is to identify the number of chromatographic modules of this invention, whether they are to be used in series or parallel flow configurations and then connect them to provide the desired fluid flow through the beds in the modules and then recover the effluent or recover the desired component retained by the chromatographic beds in a manner well known in the art. Since the plurality of chromatographic modules have substantially the same configuration, the wall effects within the modules is substantially the same. Additionally, as they have substantially the same volume and are packed substantially identical to each other there is little, preferably no detectable performance difference between the modules. Thus, when one scales up the chromatographic process by adding modules, the scalability is substantially linear. This makes predicting of results with the scaled up process much easier than that of the prior art.
Referring to
Each module 17 also is provided with a fluid outlet 11. Each fluid inlet 14 and fluid outlet 11 is surrounded by a gasket 13 which extends above a flat outside surface 15 of each module. The housing 12 contains a packed chromatographic bed (not shown, see element 32 of
Referring to
As shown as
Each chromatographic module can be prepared for use as follows: Each module will have three parts such as is shown in
To pack the chromatographic media in the device, vibration can be effected to pack the media with a minimum of voids. Suitable examples of chromatographic media include ProSep®A resin (a media available from Millipore Corporation of Billerica, Mass.), ion exchange media, agarose based media silica, carbon, controlled pore glass, hydroxyapatite or the like.
Any chromatographic media can be employed including beads, especially porous beads, monoliths or fibrous mats. Examples of materials to be purified include proteins, recombinant or natural, antibodies, enzymes, DNA or RNA fragments, plasmids or other biomolecules, synthetic molecules such as oligonucleotides, other selected molecules and the like.
Examples of suitable polymeric material for the module include but are not limited to, polycarbonates, polyesters, nylons, PTFE resins and other fluoropolymers, acrylic and methacrylic resins and copolymers, polysulfones, polyethersulfones, polyarylsulfones, polystyrenes, polyvinyl chlorides, chlorinated polyvinyl chlorides, ABS and its alloys and blends, polyolefins (e.g., low density polyethylene, high density polyethylene, and ultrahigh molecular weight polyethylene and copolymers thereof), polypropylene and copolymers thereof, and metallocene generated polyolefins as well as thermosets, rubbers and other curable polymeric materials such as polyurethanes, epoxies, fiberglass reinforced epoxies, synthetic rubbers such as silicones and the like.
In use one or more modules according to the invention and containing a selected media are mounted on a support device. At least and preferably, one end plate of the support mechanism has a corresponding inlet and outlet and optionally vent that align with those of the module of the one or more modules that is positioned against the end plate(s) having the inlet, outlet and option vent. The hydraulic press which is attached to one or both end plates is used to move the end plates toward each other and against the one or more modules and the gaskets they contain on their respective inlets, outlets and optional vents until a liquid tight seal is formed. Conduits, such as stainless steel pipe, or hoses, such as rubber or plastic hoses or tubes, from the supply of liquids (raw feedstream, equilibration buffers, wash buffers, elution buffers) to the inlet of the end plate are attached. Conduits or hoses to the filtrate side are attached to the outlet. Optionally, it may then be attached to a downstream component such as a storage tank or the next piece of equipment to be used in the filtration process, such as another support mechanism containing a different media in similarly designed modules, a polisher, a viral filter or a tangential flow filtration (TFF) device. The vent may be attached to a vent filter such as an AERVENT® gas filter available from Millipore Corporation of Billerica, Mass.
Liquid is pumped into the conduit/hose through the inlet and into the module(s). liquid exits the module(s) and exits via the outlet. If the media in the module(s) captures impurities the desired product is in the first filtrate. If the media binds to the desired product, then the impurities are in the first filtrate. In this instance, one or more washes can then be applied to remove any loosely bound impurities and then an elution buffer (such as liquid having a different pH, salt concentration conductivity, etc) as is well known in the art is pumped through the bed to elute the desired product which exits the outlet from the system.
Valves, pumps and other such commonly used devices can also be attached to the system as needed.
Two prototypes of the device as described in this patent application were in a form similar to that of
CFD(Computational Fluid Dynamics) simulations were carried out on this design to predict the shapes of the frontal curves that could be expected from the prototype.
The prototypes were each packed with 12 liters of Millipore Corp's ProSep® A protein A chromatography resin. Vibration packing using a OR65 vibrator from OLI, Inc, using an air pressure of 50 psi (approximately 15000-20000 vibrations/second) was used in a cycle of one minute vibration, two minutes no vibration for between 20 and 30 cycles to form a stable, consolidated bed of this resin.
Subsequently, the prototypes were equilibrated with purified water and challenged with a step front of 1M sodium chloride in purified water. The sodium chloride was unretained on the resin and acted as a tracer molecule to evaluate the efficiency of the packed bed.
As is evident from
This application claims the benefit of U.S. Provisional Patent Application No. 61/131,640, filed on Jun. 11, 2008, the entire contents of which are incorporated by reference herein.
Number | Date | Country | |
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61133003 | Jun 2008 | US |