Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis
Patent
1995-08-09
1998-06-16
Weiss, John G.
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
623 16, 623 18, 623 66, 523 1, 523105, 523115, A61F 202
Patent
active
057662479
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to bioimbedding materials and a process for producing the same.
BACKGROUND ART
Generally, as a material for applying to a soft tissue in a living organism (or body) or as a material for a catheter, etc., several kinds of polymers are used. These materials, however, are foreign to the living organism. Particularly, in the case of a catheter, etc. connecting the outside and inside of the living organism, bacteria is likely to enter the living organism through the opening in the skin so that inflammation or infection may easily occur. Thus, these materials cannot be used for a long time.
A contrast line, using a contrast medium such as barium sulfate or tungsten oxide and imbedded in a catheter, etc., may cause a breakage of the catheter along the contrast line, which is an uncertain factor from the viewpoints of strength. Further, a material to which a contrast medium is directly inserted may cause harm to a living organism due to the release of the contrast medium.
Hydroxyapatite is known to have an excellent biocompatibility and, therefore, is clinically used as, for example, artificial bones. However, since hydroxyapatite is extremely hard, compared to living tissue, and lacks elasticity and flexibility, hydroxyapatite is unsuitable as a material such as catheter for applying to a soft material.
DISCLOSURE OF INVENTION
In view of the state of the above-described prior art, the object of the present invention is to provide a bioimbedding material which does not cause inflammation and can function for a long time in the living organism, which has flexibility and elasticity and, further, has an excellent biocompatibility and contrastability, without requiring a contrast line.
In accordance with the present invention, there is provided a bioimbedding material comprising a mixture of ultrafine hydroxyapatite powder having a particle diameter of 2 .mu.m or less, and a polymer or oligomer.
In accordance with the present invention, there is also provided a process for producing a bioimbedding material comprising drying or thermally treating hydroxyapatite obtained by wet synthesis to form the ultrafine powder thereof, followed by mixing with a polymer or oligomer.
BRIEF DESCRIPTION OF DRAWINGS
The present invention will now be explained in detail below with reference to the drawings.
FIGS. 1 and 2, are graphs representing the results of Example 1. FIG. 1 represents the change in the tensile strength and the tearing strength of silicone rubber corresponding to the addition amount of hydroxyapatite (HA), and FIG. 2 represents the change in the thickness of a fibrous film formed around a sample.
BEST MODE FOR CARRYING OUT THE INVENTION
The composition, the shape or the structure and the embodiment of use of the bioimbedding material according to the present invention will be individually described, in detail, below.
Composition of and Production Method for the Material
"Hydroxyapatite" used in the present invention may include not only the pure product represented by Ca.sub.10 (PO.sub.4).sub.6 (OH).sub.2 in terms of the chemical composition, but also those further comprising 1-10% of a carbonate (CO.sub.3) ion, fluorine or chlorine ion, etc., instead of the OH ion. The hydroxyapatite of the present invention may also include those mainly containing the above-mentioned compounds and, additionally, to improve the sintering ability, strength, porosity, etc., may include well known various additives such as Ca.sub.3 (PO.sub.4).sub.2, MgO, Na.sub.2 O, K.sub.2 O, CaF.sub.2, Al.sub.2 O.sub.3, SiO.sub.2, CaO, Fe.sub.2 O.sub.3,MnO.sub.2, ZnO, C, SrO, PbO, BaO, TiO.sub.2, ZrO.sub.2 added thereto or mixed therewith.
The hydroxyapatite having the above-mentioned components means those having a mole ratio of Ca/P of 1.67. However, calcium phosphates alone such as deficient apatite, tricalcium phosphate, tetracalcium phosphate and octacalcium phosphate, or composite products comprising two or more of these compounds have substantially the equivalent function to those o
REFERENCES:
patent: 4846838 (1989-07-01), Takai et al.
patent: 5073373 (1991-12-01), O'Leary et al.
patent: 5178845 (1993-01-01), Constantl et al.
patent: 5376375 (1994-12-01), Rhee et al.
Aoki Hideki
Iida Takahiro
Shin Yoshiharu
Yoshizawa Kazutake
Cuddihy Francis K.
Kabushiki Kaisya Advance
Weiss John G.
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