Fibrin porous structure
AssigneeBaxter International Inc.
InventorYves Delmotte
Life of this patent
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Abstract
The present invention provides a porous structure of fibrin or fibrinogen material. The structure in its substantially dry form, having a compression strain of less than 8%, and a creep modulus higher than 1.5×106 Pa. The compression strain and creep modulus being measured for a sample having a diameter of 5 mm on which a compression of 2500 milli Newtons is exerted with a compression ramp of 500 milli Newtons per minute, after a compression release step following an initial compression of 2500 milli Newtons with a compression ramp of 500 milli Newtons per minute. After hydration, the structure has a porosity wherein at least 50% by volume of the total porosity is formed by channels with an open cross section of more than 500 μm2.
Claims33
Porous structure of fibrin or fibrinogen material, the structure comprising:
- in its substantially dry form, a compression strain of less than 8%, and a creep modulus higher than 1.5×106 Pa, said compression strain and creep modulus being measured for a sample having a diameter of 5 mm on which a compression of 2500 milli Newtons is exerted with a compression ramp of 500 milli Newtons per minute, after a compression release step following an initial compression of 2500 milli Newtons with a compression ramp of 500 milli Newtons per minute;
- and
- after hydration, such a porosity that at least 50% by volume of the total porosity is formed by channels with an open cross section of more than 500 μm2.
A process for preparing a fibrin structure comprising the steps of:
- providing a solution containing at least about 5 mg/ml fibrin or fibrinogen;
- providing a calcium inhibiting agent;
- polymerizing the solution in the presence of the calcium inhibiting agent to cause at least partial cross-linking of the fibrin or fibrinogen materials to define a partially cross-linked fibrin or fibrinogen material;
- lyophilizing the partially cross-linked, fibrin or fibrinogen material to define a porous structure having the following physical characteristics:
- in its substantially dry form, a compression strain of less than 8% and a creep modulus higher than 1.5×106 Pa, the compression strain and creep modulus being measured for a sample having a diameter of 5 mm on which a compression of 2500 milli Newtons is exerted with a compression ramp of 500 milli Newtons per minute, after a compression release step following an initial compression of 2500 milli Newtons with a compression ramp of 500 milli Newtons per minute, and
- after hydration, a porosity such that at least 50% by volume of the total porosity is formed by channels with an open cross section of more than 500 μm2.
A kit for preparing a bone substitute, said kit comprising a first chamber containing an aqueous solution containing BMP and a second container containing a fibrin or fibrinogen material having the following physical characteristics:
- in its substantially dry form, a compression strain of less than 8%, and a creep modulus higher than 1.5 106 Pa, said compression strain and creep modulus being measured for a sample having a diameter of 5 mm on which a compression of 2500 milli Newtons is exerted with a compression ramp of 500 milli Newtons per minute, after a compression release step following an initial compression of 2500 milli Newtons with a compression ramp of 500 milli Newtons per minute;
- and
- after hydration, such a porosity that at least 50% by volume of the total porosity is formed by channels with an open cross section of more than 500 μm2.
A cement for use with bones comprising:
- a solution containing a fibrin powder, and bone particles, the fibrin powder having the following physical characteristics:
- in its substantially dry form, a compression strain of less than 8%, and a creep modulus higher than 1.5×106 Pa, said compression strain and creep modulus being measured for a sample having a diameter of 5 mm on which a compression of 2500 milli Newtons is exerted with a compression ramp of 500 milli Newtons per minute, after a compression release step following an initial compression of 2500 milli Newtons with a compression ramp of 500 milli Newtons per minute;
- and
- after hydration, such a porosity that at least 50% by volume of the total porosity is formed by channels with an open cross section of more than 500 μm2.
Dependencies are inferred from the claim text.