Process of making implantable prosthesis material of modified polymeric acrylic (PMMA) beads coated with PHEMA and barium sulfate
First Claim
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1. A process for producing implantable prosthesis material comprising loose, individual, modified polymethylmethacrylate beads of a particle size which when implanted develop pore sizes that promote bone growth including the steps of:
- (a) mixing polymethylmethacrylate beads with between about 10 and 20% by volume or between about 21.5 and 43% by weight of barium sulfate of particle size less than one micron;
(b) adding between about 4 and 7% by weight (of the polymethylmethacrylate beads) of monomeric hydroxyethyl methacrylate to the polymethylmethacrylatebarium sulfate mixture, and mixing said mixture to effect uniform coating of the PMMA beads;
(c) heating the mixture produced in step (b) with a dielectric heater while in a thin layer of about 1/16" to 1/8" thickness until most of the hydroxyethyl methacrylate is polymerized;
(d) cooling the mixture to an ambient temperature between about 70 and about 80°
F.;
(e) breaking up any clumps in the mixture;
(f) boiling the mixture in water for about 2 to 3 minutes to extract any remaining monomer; and
(g) spreading out the obtained modified polymethylmethacrylate beads for air-drying or force drying.
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Abstract
This invention relates to implantable porous prostheses for use as bone or hard tissue replacements anywhere in the body. The porous implants comprise loose, individual polymeric particles of a specified size, coated with a hydrophilic material and barium sulfate particles. The prostheses are biologically compatible in the body and promote bone and tissue ingrowth and attachment. This invention also relates to a method for producing the novel prosthetic devices disclosed herein.
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1 Claim
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1. A process for producing implantable prosthesis material comprising loose, individual, modified polymethylmethacrylate beads of a particle size which when implanted develop pore sizes that promote bone growth including the steps of:
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(a) mixing polymethylmethacrylate beads with between about 10 and 20% by volume or between about 21.5 and 43% by weight of barium sulfate of particle size less than one micron; (b) adding between about 4 and 7% by weight (of the polymethylmethacrylate beads) of monomeric hydroxyethyl methacrylate to the polymethylmethacrylatebarium sulfate mixture, and mixing said mixture to effect uniform coating of the PMMA beads; (c) heating the mixture produced in step (b) with a dielectric heater while in a thin layer of about 1/16" to 1/8" thickness until most of the hydroxyethyl methacrylate is polymerized; (d) cooling the mixture to an ambient temperature between about 70 and about 80°
F.;(e) breaking up any clumps in the mixture; (f) boiling the mixture in water for about 2 to 3 minutes to extract any remaining monomer; and (g) spreading out the obtained modified polymethylmethacrylate beads for air-drying or force drying.
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Specification