Freeze-dried composite materials and processes for the production thereof
AssigneeJohnson & Johnson Medical, Inc.
InventorsWil Harvey, Peter Van Leeuwen, Tom Hyland, Will Aitken
Life of this patent
Estimating the term…
Abstract
The invention provides a sterile freeze-dried sponge, wherein at least 80% by weight of the sponge consists of collagen and oxidized regenerated cellulose in the weight ratio 60:40 to 40:60, wherein the sponge has a dry tensile strength of more than 3N and/or a wet tensile strength of more than 1 N. Preferably, the collagen has a degree of denaturation less than 20% and the sponge is substantially free of chemical cross-links. The invention also provides methods for the manufacture of sponges according to the invention.
Claims9
A method of manufacture of a freeze-dried sponge pad comprising the steps of:
- providing an acidified paste of purified collagen fibers, wherein the collagen is less than 10% denatured;
- providing oxidized regenerated cellulose fibers, wherein at least 80% of said fibers have lengths in the range of 20 μm to 1000 μm;
- combining said collagen and said ORC fibers in a homogeneous aqueous dispersion in a weight ratio of 60:40 to 40:60 collagen:ORC, said aqueous dispersion being acidified to a pH in the range of 2.8 to 3.2 and having a total solids concentration of 0.8 to 1.2% by weight;
- pouring said aqueous dispersion into trays to a depth greater than 1 cm;
- freezing the dispersion to a temperature below −30° C., followed by a temperature programmed freeze drying and dehydrothermal cross-linking to a final moisture content of 5-15% by weight;
- splitting the freeze-dried dispersion to remove surface layers and leave one or more pads;
- and
- sterilizing the one or more pads by gamma-irradiation.
Dependencies are inferred from the claim text.