Liquid purification or separation – Processes – Utilizing electrical or wave energy directly applied to...
Reexamination Certificate
2001-06-25
2004-10-26
Kim, John (Department: 1723)
Liquid purification or separation
Processes
Utilizing electrical or wave energy directly applied to...
C210S645000, C210S646000, C210S739000, C210S745000, C210S746000, C210S766000, C210S774000, C210S787000, C210S806000, C435S002000
Reexamination Certificate
active
06808638
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a method and system for concentrating liquid materials. The invention relates more specifically to a method and system for selective removal of one or more components of a temperature-sensitive, multi-component material to form a product having an increased concentration of one or more other components of the material. The present invention further relates to methods and apparatus for processing temperature-sensitive materials, such as blood plasma. In particular, the present invention relates to methods and apparatus for concentrating temperature-sensitive materials, such as blood plasma, and for processing temperature-sensitive materials, such as blood plasma, by cryoprecipitation and/or chromatography.
2. Description of the Background
Plasma is the straw-colored liquid that remains after all of the cellular components of blood have been removed. Consisting of water, electrolytes, various nutrients, immune factors and clotting proteins, plasma has many life-supporting functions. For this reason, plasma is often used for direct transfusion, primarily for cases involving massive blood loss. Many of the individual components of plasma can also be separated and used to treat a variety of diseases, with more than 100 such products now being produced by a multi-billion dollar, worldwide industry.
Thus, there is an immense demand for plasma and plasma products. However, it is not possible to obtain enough material to meet these demands. Although there has been some success in various synthetic techniques, the main source of plasma and plasma products remains the human donor. The overall donation process begins at the collection center. At this point, plasma is either separated from a whole blood donation, or obtained by apheresis, a process that takes only the plasma component of the blood from the donor. Some of the plasma is then used for direct transfusion, and some of the plasma is frozen and then thawed to obtain cold temperature insoluble proteins called cryoprecipitates. Most of the collected plasma, though, is sent to central processing facilities, where it is combined into large vats from which the individual components are then separated.
It has been found desirable for a wide variety of reasons to concentrate one or more components of multi-component materials. For example, in the biomedical field, it is often desired to increase the concentration of materials such as blood constituents, including plasma, immunoglobulins, fibrinogen and/or clotting factors, by removing water and/or other components of the material. In the pharmaceutical field, concentration of drugs or other materials produced in dilute liquid form or in solution is often required to produce an effective or commercially viable product. Food products such as condensed milk are also produced by means of material concentration processes. Material concentration processes also find application in the chemical processing industry, for example, in the removal of water from aqueous solutions, in the removal of organic solvents such as alcohols or alkanes from organic solutions, and the removal of inorganic solvents such as acids from in organic solutions. The concentrated materials may be reconstituted for use by addition of water, saline solution or other materials, or may be used or further processed in concentrated form.
Concentration of a material may be desirable in order to minimize the expense and space requirements related to storage and transportation of the material. For example, the storage and shipment of blood products typically requires expensive refrigeration equipment. The effective capacity of available equipment can be increased by minimizing the volume of the shipped or stored products through material concentration. Increased availability of blood products can save lives in emergency situations such as natural disaster or war, and can provide substantial economic savings in nonemergency applications. Concentration of a material may also be desirable in order to enhance or alter the properties or therapeutic effects of the material. For example, fibrin glue formed by concentration of fibrinogen and other components in blood plasma has found increasing application in the repair of traumatized biological tissue. The concentration of a material also may assist in, or enhance the efficiency of, additional processing of the material. For example, concentration of blood plasma reduces the volume of material to be treated in subsequent decontamination and fractionation steps, thereby reducing the time, expense and equipment requirements for these processes. Material concentration can also enhance the detection of contaminants in a product by increasing the concentration of the contaminants, thereby rendering them more easily detectable.
Previously known material concentration methods have been found to be less than fully successful for many applications. In particular, temperature-sensitive materials are often damaged by known material concentration methods. For example, forced evaporative and distillation methods of concentration, which typically involve the application of heat to the material to be concentrated, can irreversibly denature proteins or otherwise damage the product. Previously known cryoprecipitation methods of concentration, which typically involve freezing the entire quantity of material to be concentrated, can likewise damage temperature-sensitive products. Previously known filtration methods of material concentration typically suffer inefficiencies due to clogging of the filter media, necessitating frequent replacement or cleaning of the filter. Previously known methods and systems for concentrating also suffer from low yields and inefficiencies. For example, pump and line losses often consume a substantial quantity of concentrate in known methods and systems.
Thus it can be seen that a need yet exists for a method and system for concentrating temperature-sensitive materials, which method reduces or eliminates damage to the materials, reduces inefficiencies and increases yield.
It is also known to separate some proteins from blood plasma by cryoprecipitation. The basic principle of cryoprecipitation is that some plasma proteins agglomerate when frozen, and then remain agglomerated when thawed if the temperature is kept sufficiently low, no more than 5° C. This technique can thus be used to separate certain proteins, such as Factor VIII, fibrinogen, and von Willebrands factor, from bulk plasma.
Conventional cryoprecipitation techniques, however, suffer from long processing times and poor yields; these limits are indeed some of the prime motivations for the concentrator. It is therefore desirable to develop a cryoprecipitation technology specifically for concentrated plasma.
It is also known to separate and/or purify materials by chromatography. The underlying principle in chromatography is that different materials diffuse through different media at different rates. These differences in rates thus provide a means of separating the various components of complicated mixtures. Such separations are commonly used to identify individual components, such as toxins or other unknowns, and to prepare commercially valuable fractions of known mixtures, such as blood plasma.
In conventional chromatography, the target materials of interest are often organic compounds, which can be in liquid or gaseous forms. The target materials are usually dissolved in a solvent, such as alcohol. The media typically consist of absorbing materials, such as paper or gels.
The overall process amounts to a progression of equilibrium states (K. Hostettmann et al,
Preparative Chromatographic Techniques
, Springer Verlag, 1998, which is incorporated herein by reference), during which the material to be separated reaches equilibrium with the media and the solvent. The ideal situation is that the flow rates and the relative absorption strengths are balanced well enough to resolve the components.
There are, however, four majo
Kim John
Throwleigh Technologies, L.L.C.
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