Powdered oxidized cellulose
First Claim
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1. A method of making an oxidized cellulose containing carboxyl groups comprising:
- soaking a source of cellulose in a reaction mixture containing an amount of concentrated phosphoric acid and concentrated nitric acid to form an acid mixture;
thereafter adding sodium nitrite to the acid mixture to form an oxidizing mixture;
allowing the sodium nitrite to react with the acid mixture for a period of time of up to about 48 hours, said reaction occurring at a temperature ranging between 15-28°
C.;
terminating the reaction by adding an excess of water to the oxidizing mixture; and
filtering the oxidized cellulose from the oxidizing mixture, said oxidized cellulose having a degree of polymerization of 82 or less, and a degree of crystallinity of 38% or less.
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Abstract
A controlled chemical method to produce oxidized cellulose in high yields (75-95%) and different levels of oxidation (carboxyl content <25.6%, w/w), suitable for use as an immobilizing matrix or carrier for drugs, chemicals, and biological macromolecules, has been developed by reacting a cellulose material with a mixture of phosphoric acid and nitric acid and a small but adequate amounts of sodium nitrite at room temperature for a period until the desired oxidation level is obtained.
186 Citations
21 Claims
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1. A method of making an oxidized cellulose containing carboxyl groups comprising:
- soaking a source of cellulose in a reaction mixture containing an amount of concentrated phosphoric acid and concentrated nitric acid to form an acid mixture;
thereafter adding sodium nitrite to the acid mixture to form an oxidizing mixture;
allowing the sodium nitrite to react with the acid mixture for a period of time of up to about 48 hours, said reaction occurring at a temperature ranging between 15-28°
C.;
terminating the reaction by adding an excess of water to the oxidizing mixture; and
filtering the oxidized cellulose from the oxidizing mixture, said oxidized cellulose having a degree of polymerization of 82 or less, and a degree of crystallinity of 38% or less. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- soaking a source of cellulose in a reaction mixture containing an amount of concentrated phosphoric acid and concentrated nitric acid to form an acid mixture;
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16. Oxidized cellulose;
- said oxidized cellulose having a degree of polymenzation of 82 or less, and a degree of crystallinity of 38% or less.
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17. A pharmaceutical comprising:
- a drug; and
oxidized cellulose;
said oxidized cellulose having a degree of polymerization of 82 or less, and a degree of crystallinity of 38% or less. - View Dependent Claims (18, 19, 20, 21)
- a drug; and
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Current AssigneeIowa State University Research Foundation Incorporated (Iowa State University), University of Iowa Research Foundation
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Original AssigneeUniversity of Iowa Research Foundation
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InventorsKumar, Vijay
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Primary Examiner(s)Wilson, James O.
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Assistant Examiner(s)Krishnan, Ganapathy
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Application NumberUS09/711,359Time in Patent Office1,055 DaysField of Search536/30, 536/56, 536/123.1, 536/124US Class Current536/56CPC Class CodesC08B 15/04 Carboxycellulose, e.g. prep...
