CA1088056A - Method for separation of dextrans - Google Patents

Method for separation of dextrans

Info

Publication number
CA1088056A
CA1088056A CA280,663A CA280663A CA1088056A CA 1088056 A CA1088056 A CA 1088056A CA 280663 A CA280663 A CA 280663A CA 1088056 A CA1088056 A CA 1088056A
Authority
CA
Canada
Prior art keywords
fluid
compartment
mixture
dextrans
fed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA280,663A
Other languages
French (fr)
Inventor
Philip E. Barker
Frederick J. Ellison
Brian W. Hatt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fisons Ltd
Original Assignee
Fisons Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fisons Ltd filed Critical Fisons Ltd
Application granted granted Critical
Publication of CA1088056A publication Critical patent/CA1088056A/en
Expired legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08BPOLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B37/00Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof
    • C08B37/0006Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid
    • C08B37/0009Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid alpha-D-Glucans, e.g. polydextrose, alternan, glycogen; (alpha-1,4)(alpha-1,6)-D-Glucans; (alpha-1,3)(alpha-1,4)-D-Glucans, e.g. isolichenan or nigeran; (alpha-1,4)-D-Glucans; (alpha-1,3)-D-Glucans, e.g. pseudonigeran; Derivatives thereof
    • C08B37/0021Dextran, i.e. (alpha-1,4)-D-glucan; Derivatives thereof, e.g. Sephadex, i.e. crosslinked dextran

Abstract

ABSTRACT
The invention described and claimed in the specification is a new method for separation of a fluid mixture of dextrans of differing molecular weights into two fractions, which comprises (a) passing said mixture into chromatographic apparatus which comprises a plurality of compartments which contain an appropriate packing material, valve-containing conduits interconnecting the compartments to provide a closed loop column, at least one additional valve controlled fluid inlet and at least one additional valve controlled fluit outlet for each compartment, and means for sequential operation of the valves, and (b) operating the valves sequentially such that each compartment undergoes, and at any one time there is at least one compartment undergoing, the following operations:
(i) being fed with the fluid mixture to be separated, (ii) being fed with a carrier fluid, (iii) having carrier fluid and any entrained faster moving components of the fluid mixture removed therefrom, and (iv) being isolated and treated to remove any slower moving components of the fluid mixture;
the compartment being fed with fluid mixture to be separated being a compartment through which the carrier fluid passes.

Description

08/A/l~
-` lOB~OS6 ~ 2 --~his invention relates to a novel separation process.
Dextrans of suitably low molecular weights for use as plasma volume expanders, and for use in the production of iron-dextran, have for many years been made by the hydrolysis of native dextran and subsequent separation of the hydrolysate into fractions suitable for the intended end usc. The separation of the hydrolysate into various fractions has in gcneral involvcd the fractional precipitation of the dextran with aqueous ethanol of varying concentrations. This procedure is generally disadvantageous in that it involves the use of large volumes of ethanol, which produce a substantial fire hazard and also are expensive to recover, e.g. by distillation. Other methods of frac~ionating polymeric materials are also kno~Yn, and indeed some of these, notably liquid ~hase gel chromatography, are widely used on a laboratory scale, particularly for the analysis of polymeric materials. I-lowever liquid phase gel chromatography is almost invariably carried out on a batch basis and is not readily adapted to production scale operation. Furthermore the material fed to liquid phase gel chromatography columns generally has to consist of a solution containing less than about 5~ by weight of the material to be separated, the solvent being the liquid phase used on the colun~i. The use of feeds of this concentration generally leads to a concentration on the column of the material to be separated of less than about 1% by weight.

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10~3~056 We have now found that very high concentrations of dextrans may be used on sequential chromatographic equipment using an 'apparent rotation' of the column to obtain separation of the dextran into two fractions.
~le chromatographic equipment suitable for use in the process of the present invention comprises a plurality of compartments which contain an appropriate pac]cing material, valve-containing conduits interconnecting the compart~ents to provide a closed loop column, at least one additional valve controlled fluid inlet and at least one additional valve controlled fluid outlet for each compartment, and means for sequential operation of the valves such that, in use, each compartment undergoes, and at any one time there is at least one compartment undergoing, the following operations:
ti) being fed with the fluid mixture to be separated, (ii) being fed with a carrier fluid, (iii) having carrier fluid and any entrained faster moving components of the fluid mixture r~moved thererom, and (iv) being isolated and treated to remove any slower ~oving components of the fluid mixture; the compartment being fed with fluid mixture to be separated being a compartment through which the carrier fluid passes.
~le sequential operation of the valves simulates rotation of r the closed loop column in a direction counter current to the . movement of the carrier liquid. Separation occurs when the relative rates of flow of the liquid dextran~containing mixture :

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10!3~3056 _ 4 _ to be separated and the carrier liquid, together with the rate of 'apparent rotation' of the closed loop column are adjusted with respect to the relative retention of the two fractions of the dextran mixture to be separated so that the rate of 'apparent rotation' of the stationary, packed column is slower than the aster movin~ fraction, but not slower than the slower moving ~raction.
Thus according to our invention we provide a method for separation of a mixture of dextrans of differing molecular weights into two fractions, which comprises passing a solution of the mixture throu~h the above-described apparatus.
It will be appreciated that the method described above will only separate the dextran into two fractions of differing mean molecular weight. If, as is generally the case with clinical dextran, it is desired to eliminate (or at least decrease considerably the concentration of) dextrans of both too high and too low molecular weights it will be necessary either to ~ass the dextran through the apparatus twice using different, but appropriately adjusted conditions, or it will be necessary to pass the dextran through two sets of apparatus one set to remove material of too high a molecular weight and one set to remove material of too low a molecular weight.
The carrier fluid used in the process may be any convenient solvent in which tlle dextran is soluble, for ex~nple dimethyl-sulphoxide, dj~nethylfo~namide, ethanolamine, a lower (i.e. C 1 to 6) - . . , .. . . .
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ll/A~19~
` 10~38056 alkanol or, especially watcr, or admixtures thereof. In order to prevent or inhibit bacterial growth when water is used, it is sometimes preferred to use water containing from about 5 to 15~o by weight of a lower alkanol, e.gO ethanol.
The fluid feed to the chromatograph column preferably comprises a solution of the dextra~ to be separated in the same solvent as is used in the carrier fluid. The feed preferably contains from about 5~ to 30~ and preferably ~rom about 20~ to 30~ by weight of dextran.
The process of the invention may be carried out at a temperature on the column of from about 5 to 150C~ higher pressures enabling the higher temperatures. Bacterial growth may be prevented or inhibited l~hen water is the sole solvent by employing temperatures of from 70C to 100C, and these conditions are preferred. IYhen a non-aqueous solvent or a solvent mixture is employed, however, the temperature is preferably ~rom 20 to 50 and more preferably from 40 to 50C.
The process may be carried out at any suitable prcssure drop across the colllmn. ~IUS, the internal column pressure may range from below atmospheric pressure, but preferably above, to any pressure which the materials of construction of the column can withstand. Thus pressures of up to about 200 psi can normally be acco~modated using steel (e.g. stainless steel) apparatus and a suitably pressure resistant packing.
The packing used in the colunnns may be any convenient packing on which the dextran is selectively retarded dependant on molecular . . . .. ~.... ..... , ,, ,,, " , ,,, ",, , ~, , , , ~, .
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10!3~3()56 weight, e.g. porous silica, cross-linke~ dextrans (e.g. those known as 'Sephadex'*), cross-linked methacrylate polymers (e.g. those known as 'Hydrogel'* or 'Spheron'*), porous glass, cross-linked polystyrene, or agarose gels (e.g. those known as 'Sepharose'*).
The packing should enable a good flcw rate to be achieved, and should be substantially inoompressible, at the operating pressure, thus the 'Sephadex' and 'Sepharose' packings may only be used at very low pressure drops across the oolumn. The packing should not be significantly soluble or suspendable in the solvent systems used for the dextran. The packing where it is a solid packing preferably has a pore diameter in the range 50 to 5,000 and more preferably 100 to 500 Angstrom units. In particular we prefer to use porous silica or a cross-linked methacrylate polymer with an approximately 300 Angstrom unit pore diameter as the packing.
The separation is preferably carried out at a pH of from about r 4 to 8 and preferably 5 to 7.
As has been mentioned above bacterial growth can be prevented or inhibited by using an aqueous alcoholic solution of dextran in the process, or by using a high temperature. Another factor which helps to prevent bacterial growth is the use of high concentrations of dextran (within the ranges given above). If desired hcwever a bactericide, e.g. sodium azide, may be included in the liquid phase, ; and any bactericide remaining in the eluted product may, if necessary, be remove~ subsequently using conventional techniques.
* - trade marks : ~ ' ' " ;

' The product from the process of the invention may be further purified, concentrated, e.g. by evaporation, and if desired dried, e.g. by spray drying, to yield a dry product.
We have found that dextran may be used at comparatively high concentrations and viscosities in the process of the present invention in contradistiw tion to other chromatographic processes. In addition, we have found that the process enables a much sharper separation of the dextran fractions to be achieved than in the processes employed hitherto.
me two dextran fractions taken from the apparatus can be taken from points which are equidistant from the feed inlet or which are separated by different distances from the feed inlet. me optimum distanoe from the feed inlet at which to take the two fractions can be readily determined by simple experiment.
The invention is illustrated, but in no way limited by the following Examples.
Example 1 An apparatus as described in British Patent No 1418503 made up of 10 compartments each 5.1 cm in diameter and 70 cms long packed with 'Spherosil XoBO75'* silica packing of particle size 200 to 500 microns was used. A sequencing interval of 17 minutes was used to re ve about 6% of the high lecular weight end of the feed distribution.
The conditions used in and results of the fractionation are summarised in the following table.
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13/~/198 0~ 0 S 6 CHRO`~TOGRAPI~IC EQUI~lENT ~DE UP OF 10 CO'~ARl~ENTS 5.1 cm DIA x 70 cm LONG PAC~ING ~TERIAL SPI~ROSIL XOB075 PARTICLE SIZE (200-500~m) SEQU~NCING INTERVAL = 17 ~IINUTES TO RE~VE ~ 6~ OF HIGH M.W.
END OF THE FEED DISTRIBUTION.

Position of inlet or Stream Flow Rate Stream outlet stream relative Designationml!n ~ Com~osition to isolated compartments Carrier Distilled Fluid 36.5 water Isolated compartment ~1 Fluid through isolated Distilled compartment 185 water Isolated comnartment ,;~, 20.6~ w/v dextran 40 in distilled water ~ 0.02%
Feed 17.1, sodium azide Isolated compartment +5 0.42% w/v dextran in High M.W. distilled product 53.6 water Isolated compartment ~9 1.78% w/v dextran in Low M.W. distilled product 185 water Isolated compartment Compartments have been numbered in the direction of carrier fluid flow.
Example 2 In further runs using the method and apparatus of Example 1, but with differences as set out in the following table, the following separations were achieved at room temperature of Dextran 40 tmean molecular weight 40000) 14tA/198 10~38i:)56 _ 9 _ .

__ __ I-Iigh molecular wt product Low molecular ~rt _ . product Run ConFce(%d) Conc (%) molecular wt Conc (%) mean A 1.11 0,06 700C0 0.03 20000 B 20.9 0.37 82000 0~50 26000 C 19.6 0.42 66000 0.72 26000 D 20.55 0.25 82000 0.38 29000 E 26 5 0.93 64000 2.16 22000 _ ~ . . . ~ . . .
Feed ~obile phase flow Pressure flow rates (ml/min) I)extranin carrier r rate _ Sequence through- fluid input .; (ml/ Pre- Post- Purge interval put con~artment ;,; R~ min) feed feed _ (min) (gm/hr) (psi) A 10.1 49.3 59.4 244 15.0 7 15 B 10.0 50.4 60.4 272 15.0 125 40 ; C 20.0 102.1 122.1 455 7.5 236 90 ; D 10.1 99.8 109.8 413 7.5 124 55 E 40.1 99.6 139.6 420 7.5 638 210 . . ~

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Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for separation of a fluid mixture of dextrans of differing molecular weights into two fractions, which comprises (a) passing said mixture into chromatographic apparatus which comprises a plurality of compartments which contain an appropriate packing material, valve-containing conduits interconnecting the compartments to provide a closed loop column, at least one additional valve controlled fluid inlet and at least one additional valve controlled fluit outlet for each compartment, and means for sequential operation of the valves, and (b) operating the valves sequentially such that each compartment undergoes, and at any one time there is at least one compartment undergoing, the following operations:
(i) being fed with the fluid mixture to be separated, (ii) being fed with a carrier fluid, (iii) having carrier fluid and any entrained faster moving components of the fluid mixture removed therefrom, and (iv) being isolated and treated to remove any slower moving components of the fluid mixture;
the compartment being fed with fluid mixture to be separated being a compartment through which the carrier fluid passes.
2. A method according to claim 1 wherein the fluid mixture of dextrans fed to the apparatus comprises a solution of the dextrans in a solvent therefor.
3. A method according to claim 2 wherein the solvent comprises dimethylsulphoxide, dimethylformamide, ethanolamine, a C 1 to 6 alkanol or water, or a mixture thereof.
4. A method according to claim 1 wherein the fluid mixture of dextrans fed to the apparatus contains from 3 to 30% by weight of said dextrans.
5. A method according to claim 4 wherein the fluid mixture of dextrans fed to the apparatus contains from 20 to 30% by weight of said dextrans.
6. A method according to claim 1 wherein the carrier fluid employed comprises dimethylsulphoxide, dimethylformamide, ethanolamine, a C 1 to 6 alkanol or water, or a mixture thereof.
7. A method according to claim 1 wherein the pressure in the column is above atmospheric pressure.
8. A method according to claim 1 wherein the packing material in the column is porous silica, a cross-linked dextran, a cross-linked methacrylate polymer, porous glass, cross-linked polystyrene, or an agarose gel.
9. A method according to claim 1 wherein the packing material is a solid packing material having a pore diameter in the range 50 to 5,000 Angstrom units.
10. A method according to claim 9 wherein the pore diameter is in the range 100 to 500 Angstrom units.
11. A method according to claim 1 wherein the pH on the column is from 4 to 8.
CA280,663A 1976-06-16 1977-06-16 Method for separation of dextrans Expired CA1088056A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB24908/76A GB1562913A (en) 1976-06-16 1976-06-16 Fractionating fluid mixtures of dextrans
GB24908/76 1976-06-16

Publications (1)

Publication Number Publication Date
CA1088056A true CA1088056A (en) 1980-10-21

Family

ID=10219164

Family Applications (1)

Application Number Title Priority Date Filing Date
CA280,663A Expired CA1088056A (en) 1976-06-16 1977-06-16 Method for separation of dextrans

Country Status (7)

Country Link
US (1) US4104078A (en)
JP (1) JPS52154000A (en)
CA (1) CA1088056A (en)
DE (1) DE2727149A1 (en)
DK (1) DK265377A (en)
GB (1) GB1562913A (en)
SE (1) SE432597B (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5740503A (en) * 1980-08-22 1982-03-06 Seikagaku Kogyo Co Ltd Separation of saccharides
WO1991003298A1 (en) * 1989-08-31 1991-03-21 Union Oil Company Of California Continuous high performance liquid chromatography
US5382294A (en) * 1991-08-26 1995-01-17 Rimedio; Nicholas T. Chromatographic separation of organic non-sugars, colloidal matterials and inorganic-organic complexes from juices, liquors, syrups and/or molasses
FI96225C (en) 1993-01-26 1996-05-27 Cultor Oy Process for fractionation of molasses
US6663780B2 (en) 1993-01-26 2003-12-16 Danisco Finland Oy Method for the fractionation of molasses
US6258993B1 (en) 1993-09-29 2001-07-10 Regents Of The University Of Minnesota Simulated countercurrent moving bed chromatographic reactor and method for use thereof
US5795398A (en) 1994-09-30 1998-08-18 Cultor Ltd. Fractionation method of sucrose-containing solutions
US6224776B1 (en) 1996-05-24 2001-05-01 Cultor Corporation Method for fractionating a solution
WO1998032514A1 (en) 1997-01-29 1998-07-30 Amalgamated Research, Inc. Method of displacement chromatography
DK172860B1 (en) * 1998-03-25 1999-08-16 Pharmacosmos Holding As Iron dextran compound for use as a component of a therapeutic agent for the prevention or treatment of iron man
CA2426799A1 (en) * 2000-11-02 2002-07-25 Chromaceutical Advanced Technologies, Inc. Method for producing purified hematinic iron-saccharidic complex and product produced
US6929954B2 (en) * 2000-11-02 2005-08-16 Chromaceutical Advanced Technologies, Inc. Method for producing purified hematinic iron-saccharidic complex and product produced
FI20010977A (en) 2001-05-09 2002-11-10 Danisco Sweeteners Oy Chromatographic separation method
US7964568B2 (en) * 2003-05-30 2011-06-21 Chromaceutical Advanced Technologies, Inc. Synthesis of high molecular weight iron-saccharidic complexes

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2565507A (en) * 1947-07-28 1951-08-28 Tell & Usher Ltd Degradation of dextran to produce a plasma substitute
US2644815A (en) * 1948-10-15 1953-07-07 Pharmacia Ab Process for producing dextran products having substantially uniform molecular size for pharmaceutical and therapeutic preparations
US2719147A (en) * 1951-04-24 1955-09-27 Ivan A Wolff Thermal modification of dextran
US2685579A (en) * 1951-05-14 1954-08-03 American Sugar Refining Co Fractionation of dextrans with alkaline earth hydroxides
US2687368A (en) * 1951-08-06 1954-08-24 Ohio Commw Eng Co Hydrolysis of crude dextran fermentates
US2660551A (en) * 1952-03-11 1953-11-24 Harold J Koepsell Method for the production of dextran of relatively low molecular weight
US2727838A (en) * 1952-11-15 1955-12-20 Commercial Solvents Corp Process for hydrolyzing dextran
US2789066A (en) * 1953-10-14 1957-04-16 Ohio Commw Eng Co Method for hydrolyzing dextran
US2717853A (en) * 1954-07-07 1955-09-13 Commercial Solvents Corp Continuous dialysis process for the production of clinical dextran
US2988482A (en) * 1956-10-15 1961-06-13 Ohio Commw Eng Co Product and method for producing clinical dextran including ionizable calcium
US2972567A (en) * 1957-07-11 1961-02-21 Ohio Commw Eng Co Method of producing clinical dextran
US3184334A (en) * 1962-04-30 1965-05-18 Dow Chemical Co Separation of dextran from fructose using ion exchange resins
GB1418503A (en) 1972-06-14 1975-12-24 Barker P E Chromatographic apparatus
US4022637A (en) * 1976-02-23 1977-05-10 Standard Brands Incorporated Method for separation of water soluble carbohydrates

Also Published As

Publication number Publication date
DE2727149A1 (en) 1977-12-29
SE7706840L (en) 1977-12-17
US4104078A (en) 1978-08-01
JPS52154000A (en) 1977-12-21
SE432597B (en) 1984-04-09
DK265377A (en) 1977-12-17
GB1562913A (en) 1980-03-19

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