Medicinal Technologies-
Wound Dressing Material and Method for Its Preparation
Introduction
Alginate wound dressings are becoming
increasingly popular in wound management specially in
treating heavily exuding wounds. But the poor structural
integrity, poor strength of alginate fiber, uncontrolled
high absorbing property of alginate dressings are acting
as bottle neck in Alginate wound dressing to become
the most predominant type of wound dressing material.
From this point of view, a stable, stronger, covalently
bonded alginate has been developed by using bi-functional
crosslinkers through esterification reaction.
Description:
The method of preparation of covalently
cross linked Alginate gels and the composite with non
woven backing sheets is described below : (i) Preparation
of gel : Water soluble salts of alginic acid such as
sodium potassium, ammonium, alginate etc. with a specific
concentration are used and to this solution, a solution
of non-gelling salts such as sodium chloride, Potassium
chloride, Magnesium chloride etc having the desired
molecular weight are added to make a uniform gel solution.
Acid catalysts can be added to catalyse the esterification
reaction, maintaining a specific pH value. This is followed
by the addition of bifunctional cross-linking agents
and mixing thoroughly by magnetic stirrers to prepare
a more uniform gel solution. To this solution crosslinking
salt of the desired concentration is added for cross-linking
esterification reaction; (ii) Preparation of composite:
The nonwoven backing sheet preferably cellulose-based
having better absorption capacity, air permeability
is selected. Blended nonwovens prepared by mixing man
made fibers with cellulosic maters can also be used.
The nonwoven material is soaked with cross-linking salt
having a specific concentration.. Covalently cross linked
alginate gels are then coated/impregnated above the
nonwoven sheet on one side and then again dipped in
the solution of cross-linking salt to prepare the composite.
Special Features:
The covalently cross-linked alginate
gel network structure and uniform gel structure help
to obtain much stable gel as compared with only ionically
cross-linked alginate; As the length of the crosslinking
chain increases, the rigidity of the gel network reduces
and the gel can withstand more force; The networking
helps in holding the absorbed blood and physiological
fluids coming from the exuding wound; The water soluble,
insoluble and protein drugs can be loaded into the network
structure to have controlled release wound dressing
material; Due to the presence of covalently bonded crosslinkers
(as for example polyethylene glycol) the dressing will
be easily peeled off from wound surface without applying
much force.
Prospective
Users: All medical establishments like hospitals,
dispensaries, nursing homes etc.
Status of IPR
Protection: Indian Patent Application No. 736/DEL/2002
dt. 11.7.2002 with title "Development of a new
Alginate Based Wound Dressing Material."
Status of Development:
Composite dressing material on batch scale has been
prepared and tested satisfactorily in the laboratory
Major Equipment
& Facilities required: For production : Constant
Temperature reaction baths; Stirring assemblies; Coating
device (batch or continuous basis); Drying equipment;
Glass wares, etc; For quality control and testing: Test
equipment for Moisture absorption, Gel strength and
bio adhesion.
Requirement of Raw Materials/Components:
Alginate
p-toluenesulphonic acid
Sodium Chloride
Developed by : Dr. (Mrs.) Manjeet
Jassal
Department: Textile Technology
Contact:
Managing Director
Foundation for Innovation and Technology Transfer (FITT)
Indian Institute of Technology, Delhi
Hauz Khas, New Delhi-110016, INDIA
Tel : 91-011-26597167, 26857762, 26581013, 26597153
Fax : 91-011-26851169
E-mail : drkdpn@gmail.com
