MEDICAL IMPLANTS HAVING A DRUG DELIVERY COATING
Medical implants having a drug delivery coating, comprising a diffusion matrix made of a collagen matrix, a bioactive material, and a self-arranging transport barrier layer. The bioactive material is contained in the collagen matrix layer and/or the self-arranging transport barrier layer. Methods of preparing the coated implants and methods of modulating the rate of elution of a bioactive material are also provided.
1 . A coated medical implant, comprising:
a substrate; and
a first diffusion matrix on a surface of the substrate, the first diffusion matrix comprising:
a first bioactive material;
a first collagen matrix layer; and
a first transport barrier layer adjacent to the collagen matrix layer; and
a second diffusion matrix atop the first diffusion matrix, the second diffusion matrix comprising:
a second bioactive material;
a second collagen matrix layer; and
a second transport barrier layer adjacent to the collagen matrix layer.
2 . A coated medical implant according to claim 1 , wherein the first bioactive material is dispersed in the first collagen matrix layer and the second bioactive material is dispersed in the second collagen matrix layer.
3 . A coated medical implant according to claim 1 , wherein at least one of the first transport barrier layer or the second transport barrier layer is amphiphilic.
4 . A coated implant according to claim 3 , wherein at least one of the first transport barrier layer or the second transport barrier layer comprises a glyceryl ester.
5 . A coated implant according to claim 4 , wherein at least one of the first transport barrier layer or the second transport barrier layer comprises lecithin.
6 . A coated implant according to claim 1 , wherein at least one of the first diffusion matrix and the second diffusion matrix is at least partially resorbable.
7 . A coated implant according to claim 1 , wherein at least one of the first diffusion matrix and the second diffusion matrix is fully resorbable.
8 . A coated implant according to claim 1 , wherein the first diffusion matrix has a first resorption rate and the second diffusion matrix has a second resorption rate.
9 . A coated implant according to claim 1 , wherein the collagen matrix layer of the first diffusion matrix is adjacent to the implant substrate.
10 . A coated medical implant, according to claim 1 , wherein the substrate is a metal substrate.
11 . A coated medical implant, according to claim 1 , wherein the substrate includes a plurality of surface features.
12 . A coated implant according to claim 11 , wherein the metal substrate is plasma serrated.
13 . A coated implant according to claim 11 , wherein the first diffusion matrix overlies the plurality of surface features to provide asperities between the first diffusion matrix and the second diffusion matrix.
14 . A coated implant according to claim 13 , wherein the asperity has a depth equal to a thickness of at least one of the collagen matrix layer or the transport barrier layer.
15 . A coated implant according to claim 1 , wherein the bioactive material is selected from the group consisting of: antibiotics, drugs, growth factors, vitamins, nutrients, and combinations thereof.
16 . A coated implant according to claim 15 , wherein the bioactive material is an antibiotic.
17 . A coated medical implant, according to claim 1 , wherein at least one of the collagen matrix layers contains a first bioactive material and at least one of the transport barrier layers contains a second bioactive material.
18 . A coated medical implant, comprising:
a substrate;
a plurality of diffusion matrices on a surface of the substrate, each diffusion matrix comprising:
a bioactive material; and
a plurality of collagen matrix layers;
wherein each of the plurality of diffusion matrices is separated from an adjacent diffusion matrix by an asperity.
19 . A coated medical implant according to claim 18 , wherein each diffusion matrix further comprises a transport barrier layer located between the collagen matrix layers.
20 . A coated medical implant according to claim 19 , wherein at least one transport barrier layer comprises lecithin.
21 . A method of administering a bioactive material to an implant site, comprising:
coating a plurality of diffusion matrix layers on a medical implant, each diffusion matrix layer comprising:
a bioactive material;
a collagen matrix layer; and
a transport barrier layer,
implanting the medical implant in the implant site;
contacting the coated implant with a diffusion media at the implant site to release the at least one bioactive material to the implant site at a pre-determined rate.
22 . A method according to claim 21 , wherein the plurality of diffusion matrix layers is sufficiently resorbable to allow for bony tissue ingrowth.
23 . A method according to claim 21 , wherein at least one transport barrier layer comprises lecithin.
24 . A method according to claim 21 , wherein the diffusion media comprises an ambient fluid at the implant site.