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.

Keywords: Alginate, Wound, Gel, Nonwoven, Dressing

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