Method of making a hemostatic sponge wound dressing comprising subjecting the sponge to water vapor
Inventors
Roberts, Keith A. • Zia, Majid
Assignees
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Publication Number
US-9061087-B2
Publication Date
2015-06-23
Expiration Date
Abstract
A method of making a wound dressing comprises dissolving at least one hemostatic agent in at least one solvent to form a solution. The method continues by freeze drying the solution to form a sponge. The method further comprises compressing the sponge, wherein the sponge is subjected to a vapor above ambient temperature prior to or during the compression.
Core Innovation
The disclosed invention relates to manufacturing and forming a wound dressing that includes a freeze-dried hemostatic sponge. The sponge is intentionally subjected to water vapor from a vaporizer prior to and/or during compression so as to modify the sponge microstructure, including fiber/pore size and surface area. The treated sponge is then compressed to form a compressed sponge suitable for incorporation into the wound dressing.
The problem addressed is that wound dressing sponges are susceptible to cracking and detachment, and the manufacturing approach seeks to increase flexibility and adhesiveness while maintaining desired porosity/density characteristics. By intentionally applying water vapor at controlled conditions prior to and during compression, the process is stated to enhance functional outcomes connected to the sponge microstructure and the resulting material properties.
The method uses chitosan materials, including chitosan, carboxyl methyl chitosan, deacetylated chitosan, or trimethylchitosan dissolved in an aqueous solvent to form a solution. The solution is freeze dried to form a sponge, after which the sponge is intentionally exposed to water vapor for a defined time and temperature range, and then compressed to obtain a compressed sponge characterized by flexibility, adhesiveness, porosity/density, average pore diameter, thickness, and BET surface area.
Claims Coverage
Two independent claims are identified. Both claims focus on a method of making a wound dressing that uses freeze drying of a chitosan-based solution into a sponge, followed by intentional water-vapor exposure from a vaporizer for defined time and temperature, and then compressing the sponge, with the second independent claim requiring vapor exposure during compression as well.
Chitosan solution freeze drying and vapor-pretreated compression of a wound dressing sponge
Dissolving at least one of chitosan, carboxyl methyl chitosan, deacetylated chitosan, or trimethylchitosan in at least one aqueous solvent to form a solution, freeze drying the solution to form a sponge, and compressing the sponge to form a compressed sponge, wherein the sponge is intentionally subjected to water vapor from a vaporizer for 30 to 120 seconds prior to the compression, the water vapor being between 50°C and 80°C.
Chitosan solution freeze drying and vapor-pretreated and vapor-during compression of a wound dressing sponge
Dissolving at least one of chitosan, carboxyl methyl chitosan, deacetylated chitosan, or trimethylchitosan in at least one aqueous solvent to form a solution, freeze drying the solution to form a sponge, and compressing the sponge, wherein the sponge is intentionally subjected to water vapor for 30 to 120 seconds prior to the compression, the water vapor being between 50°C and 80°C, and is additionally subjected to said water vapor during the compression.
Across both independent claims, the core inventive coverage is the combination of freeze drying a chitosan-based solution into a sponge, then intentionally exposing the sponge to water vapor from a vaporizer within 30 to 120 seconds at 50°C to 80°C, followed by compression to form a compressed sponge; the second independent claim further requires continued water-vapor exposure during compression.
Stated Advantages
Increases flexibility and adhesiveness of the sponge/wound dressing.
Increases porosity/density characteristics of the sponge.
Reduces cracking and detachment.
Maintains or improves functional outcomes linked to blood cell attraction, clot formation, and adhesion as tied to the modified sponge microstructure.
Documented Applications
A hemostatic wound dressing including a freeze-dried hemostatic sponge formed by vapor-treated compression.
Use of the manufactured sponge to support blood cell attraction/red blood cells and clot formation, with adhesion to the wound dressing material.
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