GB2314856A - Cellulose Products - Google Patents

Cellulose Products Download PDF

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Publication number
GB2314856A
GB2314856A GB9713991A GB9713991A GB2314856A GB 2314856 A GB2314856 A GB 2314856A GB 9713991 A GB9713991 A GB 9713991A GB 9713991 A GB9713991 A GB 9713991A GB 2314856 A GB2314856 A GB 2314856A
Authority
GB
United Kingdom
Prior art keywords
cellulose
chitosan
treated
solution
pellicle
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.)
Granted
Application number
GB9713991A
Other versions
GB2314856B (en
GB9713991D0 (en
Inventor
Paul Frederick Hamlyn
John Crighton
Michael George Dobb
Alexandra Tasker
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.)
British Textile & Technology G
University of Leeds
Original Assignee
British Textile & Technology G
University of Leeds
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 British Textile & Technology G, University of Leeds filed Critical British Textile & Technology G
Publication of GB9713991D0 publication Critical patent/GB9713991D0/en
Publication of GB2314856A publication Critical patent/GB2314856A/en
Application granted granted Critical
Publication of GB2314856B publication Critical patent/GB2314856B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/001—Modification of pulp properties
    • D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
    • D21C9/005—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives organic compounds
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
    • A61L15/225—Mixtures of macromolecular compounds
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
    • A61L15/28—Polysaccharides or their derivatives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C08L1/02—Cellulose; Modified cellulose

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  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Epidemiology (AREA)
  • General Health & Medical Sciences (AREA)
  • Veterinary Medicine (AREA)
  • Public Health (AREA)
  • Animal Behavior & Ethology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Hematology (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Wood Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials For Medical Uses (AREA)

Abstract

Cellulose, which may be microbially produced, is treated with chitosan to form, e.g. medical dressings or pads. The cellulose may be immersed in a chitosan solution, e.g. chitosan dissolved in an acid.

Description

CELLULOSE PRODUCT This invention provides novel cellulose products.
Cellulose is known in various forms and produced by various methods in fibre form. In some forms it is used in medical e.g. wound dressings. One such form, disclosed in GB-2 131 701-A is a pellicle of microbially-produced cellulose obtained by culturing Acetobacter bacteria.
The microbially-produced pellicle has very fine cellulose fibres and can be highly absorbent, for example of wound exudate, or can remain moist for considerable periods oftime, and, by virtue of evaporation, can have a cooling effect useful in treating burns.
The present invention enhances the properties of cellulose, especially microfibrillar cellulose such as is microbially produced, and in particular enhances its properties in medical and particularly wound dressings.
The invention comprises cellulose treated with chitosan.
The cellulose can be microfribillar and in particular microbially-produced cellulose, more particularly never-dried, microbially-produced cellulose, and the invention comprises medical dressings or pads, e.g. liquid-soaked for medical applications made therefrom.
The chitosan content by weight may be of the order of 100% of the weight of the cellulose weight.
In addition, the dressing or pad can be treated with a medication, and may be supported or reinforced with a supporting or reinforcing backing.
The dressing or pad may be packed, wet, in an impermeable package, and may be packed with a reduced liquid loading (as by pressing liquid out from it) permitting further absorption of liquid e.g. of wound exudate.
The invention also comprises a method for making a chitosan-treated cellulose fibre product comprising immersing the cellulose in a solution of chitosan.
The chitosan may be dissolved in an acid such as acetic and/or citric acid, which may be in 1-6% solution, preferably 2%, the chitosan solution being a 1-4% preferably 2% solution. The cellulose may be immersed for at least one hour, preferably 3 hours in the chitosan solution, and the immersion may proceed at room temperature.
The cellulose may be drip-dried after the immersion and washed, washing preferably being repeated or continued, in distilled water, until the pH is 7, and it may then be sterilised, e.g. autoclaved.
While any fibrous cellulose product can be treated according to the invention, the advantages are perhaps most appreciated when the cellulose is a microbially-produced, never-dried pellicle. GB-2 131 701-A suggests using a particular Acetobacter bacteria, A.xylinium; A.pasteurianus can also be used to good effect.
The bacteria may be cultured in liquid nutrient medium at an initial pH of between 5.5 and 7 and at a temperature between 15 and 25"C, preferably at an initial pH of 7 and a temperature of 29"C | + 1 "C.
The liquid nutrient medium may comprise glucose (20g), peptone (5g), yeast extract (5g), sodium dihydrogen phosphate (2.7g) and citric acid (1.1 5g) in 1 litre distilled water.
The pellicle should be cultured, for best results, in a substantially morticulen culturing medium, the time of cultivation being dependent on the thickness of fleece or pad required - several hours to several days, typically.
The harvested pellicle may, after drawing and pressing out much of its water, be soaked in aqueous sodium hydroxide to remove the bacteria, then immersed in an acid such as hydrochloric acid to neutralise the alkali.
Production of a never-dried pellicle of bacterial cellulose and incorporation of chitosan will now be described.
Acetobacter bacteria (preferably A.pasteurianus) are cultured in liquid nutrient medium as reported by Schramm and Hestrim (J. Biochem., , 1954) at an initial pH of between 5.5 and 7.0 (preferably 7.0) and at a temperature of between 15 and 35"C, preferably 29 + 1 C. The recipe for the medium is 20.0g glucose, 5.Og peptone, 5.Og yeast extract, 2.70g sodium dihydrogen phosphate, 1.15g citric acid and 1 litre distilled water.
A culture tray (100mm x 200mm) is filled with SOOml of the culture medium, then covered with an autoclavable bag and sterilised. To the sterile medium are added 200 microlitres of inoculum from a previously inoculated stock flask (2-3 days old) and the tray placed in an unlit incubator at 29 + 1 C and left undisturbed for 14 days.
The resulting pellicle is harvested from the tray and gently pressed between absorbent sheets to expel about 80% of its liquid content before soaking in 3% aqueous sodium hydroxide solution for 12 hours to remove the bacteria. The pellicle is pressed again and the soaking and pressing repeated twice. The pellicle is then immersed in 3% aqueous hydrochloric acid for 3 hours to neutralise the alkali followed by pressing between absorbent sheets to remove about 80% of the liquid.
The pellicle is then transferred to a bath of distilled water and repeatedly pressed and allowed to reabsorb fresh water until the pH is about 7.0 and all the sodium chloride salt removed.
The clean pellicle can be stored temporarily in distilled water or, for longer periods, in ethanol at a temperature between 0 and 5"C.
A never-dried pellicle thus obtained is immersed in a 1-4%, preferably 2% solution of chitosan in acetic and/or citric acid (1-6%, preferably 2%) for 3 hours at room temperature (16-25"C, preferably 20"C). The pellicle is then removed and allowed to drip-dry for at least 10 minutes and then washed in distilled water for 2 hours. The washing process is repeated at least twice or until the pH is about 7.0.
The chitosan-treated cellulose pellicle is then sterilised in an autocalve, in autocavable, sealable bags, for 20 minutes at 1200C, 2-3 atmospheres pressure. Once sterilised the bag can be sealed and stored at a temperature between 0 and 5"C.
The chitosan-treated pellicle can be used for all of the purposes mentioned in GB-2 131 701-A with enhanced wound healing properties.

Claims (30)

1. Cellulose treated with chitosan.
2. Microfribrillar cellulose treated with chitosan.
3. Microbially-produced cellulose treated with chitosan.
4. Never-dried microbially-produced cellulose treated with chitosan.
5. A medical dressing made from cellulose treated with chitosan according to any one of claims 1 to 4.
6. A pad for medical applications comprising a sterile, liquid-soaked pellicle of microbially-produced cellulose, treated with chitosan.
7. A dressing or pad according to claim 5 or claim 6, of which the chitosan content by weight is of the order of 100% of the weight of the cellulose weight.
8. A dressing or pad according to any one of claims 5 to 7, treated with a medication.
9. A dressing or pad according to any one of claims 5 to 7, supported or reinforced with a supporting or reinforcing backing.
10. A dressing or pad according to any one of claims 5 to 9, packed, wet, in an impermeable package.
11. A dressing or pad according to claim 10, packed with a reduced liquid loading permitting further absorption of liquid e.g. of wound exudate.
12. A method for making a chitosan-treated cellulose fibre product comprising immersing the cellulose in a solution of chitosan.
13. A method according to claim 12, in which the chitosan is dissolved in an acid.
14. A method according to claim 13, in which the acid is acetic and/or citric acid.
15. A method according to claim 14, in which the acid is a 1-6% solution.
16. A method according to claim 15, in which the acid is a 2% solution.
17. A method according to any one of claims 13 to 16, in which the chitosan solution is a 1-4% solution.
18. A method according to claim 17, in which the chitosan solution is a 2% solution.
19. A method according to any one of claims 12 to 18, in which the cellulose is immersed for at least one hour, preferably 3 hours in the chitosan solution.
20. A method according to any one of claims 12 to 18, in which the immersion proceeds at room temperature.
21. A method according to any one of claims 12 to 20, in which the cellulose is drip-dried after the immersion.
22. A method according to any one of claims 12 to 21, in which the cellulose is washed after the immersion.
23. A- method according to claim 22, in which the cellulose is repeatedly washed after immersion.
24. A method according to claim 22 or claim 23, in which the washing is effected in distilled water.
25. A method according to any one of claims 22 to 24, in which washing is continued until the pH is 7.
26. A method according to any one of claims 12 to 25, in which the treated cellulose is sterilised.
27. A method according to claim 26, in which the treated cellulose is autoclaved.
28. A method according to any one of claims 12 to 27, in which the cellulose fibre product is a microbially-produced, never-dried pellicle.
29. A method according to claim 28, in which the pellicle is prepared from Acetobacter bacteria.
30. A method according to claim 29, in which the pellicle is immersed in an acid such as hydrochloric acid to neutralise the alkali.
30. A method according to claim 29, in which the Acetobacter bacteria comprise Acetobacter pasteurianus.
31. A method according to claim 29 or claim 30, in which the bacteria are cultured in liquid nutrient medium at an initial pH of between 5.5 and 7 and at a temperature between 15 and 35"C.
32. A method according to claim 31, in which the initial pH is 7 and the temperature is 29"C + 1"C.
33. A method according to claim 31 or claim 32, in which the liquid nutrient medium comprises glucose (20g), peptone (5g), yeast extract (5g), sodium dilydrogen phosphate (2.7g) citric acid (1.1 5g) and 1 litre distilled water.
34. A method according to any one of claims 28 to 33, in which the pellicle is cultured in a substantially motionless culturing medium.
35. A method according to any one of claims 28 to 34, in which the harvested pellicle is soaked in aqueous sodium hydroxide to remove the bacteria.
36. A method according to claim 35, in which the pellicle is immersed in an acid such as hydrochloric acid to neutralise the alkali.
Amendments to the claims have been filed as follows 1. A pad for medical applications comprising a sterile, liquid-soaked pellicle of microbially-produced cellulose, treated with chitosan.
2. A pad according to claim 1, of which the chitosan content by weight is of the order of 100% of the weight of the cellulose weight.
3. A pad according to either one of claims 1 or 2, treated with a medication.
4. A pad according to either one of claims 1 or 2, supported or reinforced with a supporting or reinforcing backing.
5. A pad according to any one of claims 1 to 4, packed, wet, in an impermeable package.
6. A pad according to claim 5, packed with a reduced liquid loading permitting further absorption of liquid e.g. of wound exudate.
7. A method for making a chitosan-treated cellulose fibre product comprising immersing the cellulose in a solution of chitosan, the chitosan being dissolved in an acid.
8. A method according to claim 7, in which the acid is acetic and/or citric acid.
9. A method according to claim 8, in which the acid is a 1-6% solution.
10. A method according to claim 9, in which the acid is a 2% solution.
11. A method according to any one of claims 7 to 10, in which the chitosan solution is a 1-4% solution.
12. A method according to claim 11, in which the chitosan solution is a 2% solution.
13. A method according to any one of claims 7 to 12, in which the cellulose is immersed for at least one hour, preferably 3 hours in the chitosan solution.
14. A method according to any one of claims 7 to 13, in which the immersion proceeds at room temperature.
15. A method according to any one of claims 7 to 14, in which the cellulose is drip-dried after the immersion.
16. A method according to any one of claims 7 to 15, in which the cellulose is washed after the immersion.
17. A method according to claim 16, in which the cellulose is repeatedly washed after immersion.
18. A method according to claim 16 or claim 17, in which the washing is effected in distilled water.
19. A method according to any one of claims 16 to 18, in which washing is continued until the pH is 7.
20. A method according to any one of claims 7 to 19, in which the treated cellulose is sterilised.
21. A method according to claim 20, in which the treated cellulose is autoclaved.
22. A method according to any one of claims 7 to 21, in which the cellulose fibre product is a microbially-produced, never-dried pellicle.
23. A method according to claim 22, in which the pellicle is prepared from Acetobacter bacteria.
24. A method according to claim 23, in which the Acetobacter bacteria comprise Acetobacter pasteurianus.
25. A method according to claim 23 or claim 24, in which the bacteria are cultured in liquid nutrient medium at an initial pH of between 5.5 and 7 and at a temperature between 15 and 35"C.
26. A method according to claim 25, in which the initial pH is 7 and the temperature is 29"C + 1"C.
27. A method according to claim 25 or claim 26, in which the liquid nutrient medium comprises glucose (20g), peptone (5g), yeast extract (5g), sodium dilydrogen phosphate (2.7g) citric acid (1.1 5g) and 1 litre distilled water.
28. A method according to any one of claims 22 to 27, in which the pellicle is cultured in a substantially motionless culturing medium.
29. A method according to any one of claims 22 to 28, in which the harvested pellicle is soaked in aqueous sodium hydroxide to remove the bacteria.
GB9713991A 1996-07-03 1997-07-03 Cellulose product Expired - Fee Related GB2314856B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GBGB9613957.1A GB9613957D0 (en) 1996-07-03 1996-07-03 Cellulose product

Publications (3)

Publication Number Publication Date
GB9713991D0 GB9713991D0 (en) 1997-09-10
GB2314856A true GB2314856A (en) 1998-01-14
GB2314856B GB2314856B (en) 2000-04-12

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GB9713991A Expired - Fee Related GB2314856B (en) 1996-07-03 1997-07-03 Cellulose product

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002052028A1 (en) * 2000-12-22 2002-07-04 Degussa Bioactives Deutschland Gmbh & Co. Kg Microbially produced, physiologically compatible, permeable film comprised of cellulose that contains chitosan
US6676645B1 (en) * 1999-03-25 2004-01-13 Paul-Hartmann-Strasse Ag Breast-milk absorbent pad
GB2393120A (en) * 2002-09-18 2004-03-24 Johnson & Johnson Medical Ltd Compositions for wound treatment
US6827727B2 (en) 2001-12-18 2004-12-07 Radi Medical Systems Ab Method and device for applying external pressure in combination with coagulant treatment of puncture wounds
CN103055344A (en) * 2012-12-31 2013-04-24 上海昌颌医药科技有限公司 Bacterial cellulose/chitosan composite medical dressing and preparation method thereof
EP3250244B1 (en) 2015-01-27 2021-08-04 Medtrade Products Limited Composition for a wound dressing

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109700785A (en) * 2018-11-12 2019-05-03 广州汇朗无纺制品有限公司 A kind of Rubus parvifolius Cellulose/Chitosan composite membrane for treating 2 grades of diabetes

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0393825A1 (en) * 1989-04-21 1990-10-24 Japan as represented by Director-General, Agency of Industrial Science and Technology Novel water-absorptive composite material and method for the preparation thereof
GB2248639A (en) * 1990-08-22 1992-04-15 Agency Ind Science Techn Process of producing biodegradable sheet formed of cellulose and chitosan
JPH05186945A (en) * 1992-01-13 1993-07-27 Fuji Spinning Co Ltd Nonwoven fabric
JPH05295005A (en) * 1992-04-21 1993-11-09 Nakano Vinegar Co Ltd Biodecomposable polymeric substance

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0393825A1 (en) * 1989-04-21 1990-10-24 Japan as represented by Director-General, Agency of Industrial Science and Technology Novel water-absorptive composite material and method for the preparation thereof
GB2248639A (en) * 1990-08-22 1992-04-15 Agency Ind Science Techn Process of producing biodegradable sheet formed of cellulose and chitosan
JPH05186945A (en) * 1992-01-13 1993-07-27 Fuji Spinning Co Ltd Nonwoven fabric
JPH05295005A (en) * 1992-04-21 1993-11-09 Nakano Vinegar Co Ltd Biodecomposable polymeric substance

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
WPI Abstract Accession No. 93-270126/199334 & JP 05186945 A (FUJI) 27.07.93 (see abstract) *
WPI Abstract Accession No. 93-392671/199349 & JP 5295005 A (NAKANO) 09.11.93 (see abstract) *
WPI Abstract Accession No. 93-408355/199351 & JP 05305129 A (A. IND. SCI.) 19.11.93 (see abstract) *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6676645B1 (en) * 1999-03-25 2004-01-13 Paul-Hartmann-Strasse Ag Breast-milk absorbent pad
WO2002052028A1 (en) * 2000-12-22 2002-07-04 Degussa Bioactives Deutschland Gmbh & Co. Kg Microbially produced, physiologically compatible, permeable film comprised of cellulose that contains chitosan
US6827727B2 (en) 2001-12-18 2004-12-07 Radi Medical Systems Ab Method and device for applying external pressure in combination with coagulant treatment of puncture wounds
GB2393120A (en) * 2002-09-18 2004-03-24 Johnson & Johnson Medical Ltd Compositions for wound treatment
CN103055344A (en) * 2012-12-31 2013-04-24 上海昌颌医药科技有限公司 Bacterial cellulose/chitosan composite medical dressing and preparation method thereof
EP3250244B1 (en) 2015-01-27 2021-08-04 Medtrade Products Limited Composition for a wound dressing

Also Published As

Publication number Publication date
GB2314856B (en) 2000-04-12
GB9613957D0 (en) 1996-09-04
GB9713991D0 (en) 1997-09-10

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20020703