US4606824A
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Modified cellulose separation matrix
Assignee: Specialty Materials Inc
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Filing: 1984-10-26
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Granted: 1986-08-19
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Expires: 2004-10-26
Abstract
Abstract A cellulose-containing separation media for effecting separation of particulate and/or molecular components from a liquid, wherein the cellulose in the separation media is essentially free of non-specific pyrogenic activity as measured by the LAL test. The separation media include filtration media and chromatographic media.
Inventors
- 👤 Chaokang Chu
- 👤 Richard A. Babineau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:22
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/28; B01J20/28014; B01J20/28033; A; A61; A61L; A61L2/00; A61L2/02; A61L2/022; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/18; B01J20/28028; B01J20/28052
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
72 words
A method of substantially eliminating false positive Limulus Amebocyte Lysate ("LAL") tests for pyrogen from an effluent obtained from passing a biological liquid through a cellulose containing separation media comprising substituting for said separation media a cellulose containing separation media wherein said cellulose contains at least about 90% alpha-cellulose and is essentially free of non-specific pyrogenic reactivity as measured by the LAL tests, whereby said false positive LAL tests are substantially eliminated.
Claim 2
Independent Claim
72 words
A method of substantially eliminating false positive Limulus Amebocyte Lysate ("LAL") tests for pyrogen from an effluent obtained from passing a biological liquid through a cellulose containing separation media comprising substituting for said separation media a cellulose containing separation media wherein said cellulose contains at least about 90% alpha-cellulose and is essentially free of non-specific pyrogenic reactivity as measured by the LAL tests, whereby said false positive LAL tests are substantially eliminated.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein said LAL test is the gel-clot test.
Claim 4
Dependent Claim
13 words
The method of claim 1 wherein said LAL test is the MS-2 test.
Claim 5
Dependent Claim
11 words
The method of claim 1 wherein the separation media is electropositive.
Claim 6
Dependent Claim
13 words
The method of claim 1 wherein said separation media is a filtration media.
Claim 7
Dependent Claim
88 words
The method according to claim 5 wherein said filtration media comprises a micro-porous filter sheet of uniform porosity comprising at least about 20 wt.% of fine particulate and not more than about 80 wt.%, distributed within an interfelted matrix of cellulose fibers, said cellulose fibers being prepared from a cellulose pulp mixture comprising an unrefined cellulose pulp having a Canadian Standard Freeness of from about +400 to about +800 ml., and a highly refined cellulose pulp having a Canadian Standard Freeness of from +100 to about -600 ml.
Claim 8
Dependent Claim
17 words
The method of claim 6 wherein the microporous filter sheet contains about 40-70 wt.% of fine particulate.
Claim 9
Dependent Claim
15 words
The method of claim 6 wherein said interfelted matrix of cellulose fibers comprises 80-20 wt.%.
Claim 10
Dependent Claim
26 words
The method of claim 8 wherein the ratio of said unrefined cellulose pulp to said highly refined cellulose pulp is from about 0.1:1 to about 10:1.
Claim 11
Dependent Claim
15 words
The method of claim 9 wherein said ratio is from about 0.2:1 to about 1:1.
Claim 12
Dependent Claim
10 words
The method of claim 6 further containing a charge modifier.
Claim 13
Dependent Claim
21 words
The method of claim 11 wherein said charge modifier is selected from cationic silica, melamine-formaldehyde cationic colloid, and polyamido polyamine epichlorohydrin.
Claim 14
Dependent Claim
21 words
The method of claim 12 wherein the surfaces of the fine particulate and the cellulose pulps possess a positive zeta potential.
Claim 15
Dependent Claim
13 words
The method of claim 12 wherein the charged modifier is polyamido polyamine epichlorohydrin.
Claim 16
Dependent Claim
24 words
The method of claim 6 wherein at least a portion of said fine particulate is selected from fumed silica, fumed alumina, or activated carbon.
Claim 17
Dependent Claim
14 words
The method of claim 1 wherein said separation media is a chromatographic separation media.
Claim 18
Dependent Claim
57 words
The method of claim 16 wherein the chromatographic separation media comprises a solid stationary phase substantially homogenous with respect to each component thereof, said solid stationary phase comprising a porous matrix of cellulose fiber having particulate immobilized therein, at least one of said cellulose or particulate therein having a chromatographic functionality and being effective for chromatographic separation.
Claim 19
Dependent Claim
54 words
The method of claim 17 wherein said porous matrix of cellulose fibers comprises unrefined cellulose pulp having a Canadian Standard of Freeness of from about +400 ml to about +800 ml in admixture with a highly refined cellulose pulp having a Canadian Standard of Freeness of from about +100 ml to about -600 ml.
Claim 20
Dependent Claim
25 words
The method of claim 18 wherein the ratio of said unrefined cellulose pulp to said refined cellulose pulp is from about 0.1:1 to about 10:1.
Claim 21
Dependent Claim
15 words
The method of claim 19 wherein said ratio is from about 0.2:1 to about 1:1.
Claim 22
Dependent Claim
13 words
The method of claim 19 wherein said particulate comprises about 20-80 wt.% thereof.
Claim 23
Dependent Claim
13 words
The method of claim 21 wherein said particulate comprises about 40-70 wt.% thereof.
Claim 24
Dependent Claim
20 words
The method of claim 17 wherein said solid stationary phase comprises a plurality of sheets of said solid stationary phase.
Claim 25
Dependent Claim
12 words
The method of claim 16 wherein said media is an ion-exchange media.
Claim 26
Dependent Claim
13 words
The method of claim 16 wherein said media is an affinity chromatographic media.
Claim 27
Dependent Claim
14 words
The method of claim 16 wherein said media is a reverse phase chromatographic media.
Claim 28
Dependent Claim
26 words
The method of claim 17 wherein said cellulose comprises refined and unrefined cellulose, wherein each of said refined and unrefined cellulose consists of highly purity cellulose.
Claim 29
Dependent Claim
14 words
The method of claim 17 wherein said chromatographic separation media contains a charge modifier.
Claim 30
Dependent Claim
19 words
The method of claim 28 wherein said charge modifier is selected from cationic silica, melamine formaldehyde, or polyamido-polyamine epichlorohydrin.
Claim 31
Dependent Claim
23 words
The method of claim 17 wherein at least a portion of said particulate is selected from fumed silica, fumed alumina, or activated carbon.
Claim 32
Dependent Claim
93 words
The method of claim 16 wherein said: cellulose is covalently bonded to a synthetic polymer, said synthetic polymer made from (a) a polymerizable compound which has a chemical group capable of direct or indirect covalent coupling to said cellulose; and (b) one or more polymerizable compounds containing: (i) an ionizable chemical group, (ii) a chemical group capable of transformation to an ionizable chemical group, (iii) a chemical group capable of causing the covalent coupling of said synthetic polymer to an affinity ligand or a biologically active molecule, or (iv) a hydrophobic chemical group.
Claim 33
Dependent Claim
14 words
The method of claim 1 wherein said cellulose is produced by the sulphite process.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-18 | 1990-02-17 | 1990-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-18 | 1994-02-17 | 1994-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-18 | 1998-02-17 | 1998-08-19 | $7700.00 | Window Closed / Lapsed |