Method of making a hemostatic sponge wound dressing comprising subjecting the sponge to water vapor
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.
1. A method of making a wound dressing, comprising:
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.
2. The method of claim 1 , wherein:
the at least one aqueous solvent comprises acetic acid.
3. The method of claim 1 , wherein freeze drying the solution to form a sponge comprises:
freezing the solution in a mold at a temperature between −35 and −80° C., wherein the solution becomes a solid material; and
sublimating water from the solid material.
4. The method of claim 1 , wherein the vaporizer is selected from the group consisting of: a boiler, a direct-fired vaporizer, an electric vaporizer, an adiabatic humidifier, an isothermic humidifier, an ultrasonic humidifier, and a water bath vaporizer.
5. The method of claim 1 , wherein the sponge is compressed at a pressure between 120 to 3,000 psi for 20 to 120 seconds.
6. The method of claim 1 , wherein:
the sponge has a first thickness prior to the compression;
the sponge is compressed until it has a second thickness; and
the second thickness is one-fourth to one-sixteenth of the first thickness.
7. The method of claim 1 , wherein the compressed sponge has a porosity of 60 to 80 percent as measured by mercury intrusion.
8. The method of claim 1 , wherein the compressed sponge has an average pore diameter of 25 to 30 microns.
9. The method of claim 1 , wherein the compressed sponge has a density of 0.20 g/cm 3 to 0.40 g/cm 3 .
10. The method of claim 1 , wherein the compressed sponge: is less than 0.20 inches thick; and has a BET surface area greater than 0.50 m 2 /g.
11. The method of claim 10 , wherein the compressed sponge has a porosity greater than 60 percent as measured by mercury intrusion.
12. The method of claim 1 , wherein the compressed sponge exhibits adhesiveness from 2.85 to 5.00 ft.lb/in 2 .
13. A method of making a wound dressing, comprising:
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.