Antimicrobial fibres
Described is a method of manufacturing carboxymethyl cellulose (CMC) fibres containing an antimicrobial, the fibres being suitable for use in the preparation of wound dressings, wherein the antimicrobial is selected from the group consisting of a biguanide, a biguanide derivative, octenidine, taurolidine, and a combination of two or more thereof, the method comprising, submerging CMC fibres comprising at least 95 wt % carboxymethylcellulose on a dry weight basis in a treatment solution for a duration adequate to provide the CMC fibres containing an antimicrobial, the treatment solution comprising the antimicrobial and at least 70 wt % of a water-miscible organic solvent selected from C 1 -C 4 alkanols, C 3 -C 5 ketones, and a combination of two or more thereof. Anti-microbial CMC fibres obtained by the methods and wound dressings containing such fibres are also described.
1 . A method of manufacturing carboxymethylcellulose (CMC) fibres containing an antimicrobial, the fibres being suitable for use in the preparation of wound dressings, wherein the antimicrobial is selected from the group consisting of a biguanide, a biguanide derivative, octenidine, taurolidine, and a combination of two or more thereof, the method comprising:
submerging CMC fibres comprising at least 95 wt % carboxymethylcellulose on a dry weight basis in a treatment solution, the treatment solution comprising:
a) the antimicrobial; and
b) at least 70 wt % of a water-miscible organic solvent selected from C 1 -C 4 alkanols, C 3 -C 5 ketones, and a combination of two or more thereof;
for a duration adequate to provide the CMC fibres containing an antimicrobial.
2 . The method according to claim 1 , wherein the CMC fibres submerged in the treatment solution are continuous filament fibres.
3 . The method according to claim 1 wherein the antimicrobial is polyhexamethylene biguanide (PHMB).
4 . The method according to claim 1 , wherein the treatment solution comprises from 1-10 wt % of the antimicrobial agent relative to the total weight of the solution.
5 . The method according to claim 1 , wherein the treatment solution comprises water in an amount of from 5-25 wt % relative to the weight of the solution.
6 . The method according to claim 1 , wherein the treatment solution comprises the water-miscible organic solvent in an amount of from 70-85 wt % relative to the total weight of the solution.
7 . The method according to claim 1 , wherein the water-miscible organic solvent is selected from one or more of methanol, ethanol, propanol, isopropanol, and acetone.
8 . The method according to claim 7 , wherein the water-miscible organic solvent comprises at least 90 wt % ethanol relative to the total weight of the water-miscible organic solvent, optionally at least 95 wt % ethanol.
9 . The method according to claim 1 , wherein the step of submerging in CMC fibres in the treatment solution is preceded by a process of forming the CMC fibres, the process of forming the CMC fibres comprising:
reacting cellulose fibres with a carboxymethylating agent to provide carboxymethylcellulose (CMC) fibres.
10 . The method according to claim 1 , wherein the step of submerging the CMC fibres in the treatment solution is preceded by a step of washing the CMC fibres with a pre-treatment wash solution.
11 . The method according to claim 1 , wherein the treatment solution is maintained at a temperature within the range of from 20° C. to 50° C. during the submerging step.
12 . The method according to claim 1 , wherein the CMC fibres are submerged in the treatment solution for a duration of from 15 to 35 minutes.
13 . The method according to claim 1 , wherein the step of submerging the CMC fibres is followed by washing the CMC fibres containing antimicrobial with a post-treatment wash solution, the post-treatment wash solution comprising:
(i) at least 98 wt % of a water-miscible organic solvent selected from C 1 -C 4 alkanols, C 3 -C 5 ketones, and a combination of two or more thereof; and optionally
(ii) a spin finish agent, optionally from 0.1-2.0 wt % spin finish agent.
14 . The method according to claim 1 , wherein the CMC fibres comprise from 0.05 to 0.8 carboxymethyl groups per glucose unit as determined by potentiometric titration.
15 . A carboxymethylcellulose (CMC) fibre containing an antimicrobial within the polymer matrix of the carboxymethylcellulose fibre, wherein the antimicrobial is selected from a biguanide, a biguanide derivative, octenidine, taurolidine, and a combination of two or more thereof, for use in the preparation of wound dressings, wherein the antimicrobial is dispersed throughout the polymer matrix of the CMC fibre.
16 . The CMC fibre containing an antimicrobial according to claim 15 , wherein the antimicrobial is present in the fibre in an amount of from 0.3 to 1.1 wt %, relative to the total weight of the fibre.
17 . The CMC fibre containing an antimicrobial according to claim 15 , wherein the antimicrobial is polyhexamethylene biguanide (PHMB).
18 . A woven, non-woven or knitted material comprising CMC fibres according to claim 15 .
19 . A non-woven material comprising entangled CMC fibres according to claim 15 , wherein the non-woven material exhibits a conformability characterised by an overhang length of up to 6.5 cm in the long dimension, as determined by the Cantilever method described in ASTM D1388-08.
20 . A wound dressing comprising CMC fibres according to claim 15 .