Therapeutic driving layer for a medical device
The present invention regards the delivery of therapeutic at a target site. Systems that employ the present invention may employ a medical device sized to be inserted into a target site, a driving layer covering at least a portion of an accessible surface of the medical device, and a therapeutic interfaced with at least a portion of the driving layer. In this system, the driving layer may have a material characteristic that serves to release the therapeutic from the medical device when the medical device is at the target site. Other systems that employ the invention may also have properties that include having a driving layer with a higher solubility than the therapeutic at the target site, a medical device that is hydrophobic while the therapeutic is hydrophilic, and a coating covering at least a portion of the therapeutic.
1 . A system for delivering therapeutic to a target site, the system comprising:
a medical device sized to be positioned at a target site,
the medical device having an accessible surface;
a driving layer covering at least a portion of the accessible surface of the medical device; and
a therapeutic in physical communication with at least a portion of the driving layer,
at least a portion of the therapeutic being a greater distance from the accessible surface of the medical device than the driving layer,
the driving layer having a material characteristic that serves to increase the release of the therapeutic from the medical device when the medical device is at the target site as compared to the use of the same medical device and therapeutic at the same target site without the use of the driving layer.
2 . The system of claim 1 wherein the driving layer has a higher solubility at the target site than the therapeutic at the target site.
3 . The system of claim 1 wherein the medical device is hydrophobic and the therapeutic is hydrophilic.
4 . The system of claim 1 further comprising:
a coating covering at least a portion of the therapeutic.
5 . The system of claim 1 wherein the degradation of the driving layer at the target site over time serves as a material characteristic of the driving layer acting to release therapeutic from the medical device.
6 . The system of claim 1 wherein a material characteristic of the driving layer also serves to retain the therapeutic on the medical device prior to the release of the therapeutic from the medical device.
7 . The system of claim 1 wherein the driving layer is a protein and the therapeutic is DNA.
8 . The system of claim 1 wherein the medical device is a stent.
9 . The system of claim 8 wherein the stent has an inside surface and an outside surface and both the inside surface and the outside surface of the stent are at least both partially covered with a driving layer, a therapeutic, and a coating.
10 . The system of claim 1 wherein the driving layer is a transfection agent for the therapeutic.
11 . The system of claim 1 wherein the driving layer has a higher rate of degradation from the medical device than the therapeutic when the medical device is at a target site.
12 . The system of claim 1 wherein the driving layer has a higher rate of degradation from the medical device than the therapeutic when the medical device is at a target site and wherein the driving layer has a higher solubility at the target site than the therapeutic.
13 . The system of claim 1 wherein the driving layer is an ionic salt.
14 . The system of claim 1 wherein the driving layer is an ionic surfactant.
15 . The system of claim 1 wherein the driving layer is a non-ionic surfactant.
16 . The system of claim 1 wherein the driving layer is a lipid.
17 . The system of claim 1 wherein the driving layer is a polysaccharide.
18 . The system of claim 1 wherein the driving layer is dextran.
19 . The system of claim 1 wherein the driving layer is a foaming agent.
20 . The system of claim 1 wherein the driving layer is a block co-polymer.
21 . The system of claim 1 wherein the medical device is a bone implant.
22 . The system of claim 1 wherein the driving layer effects the complete release of the therapeutic from the medical device when the medical device is at the target site.
23 . The system of claim 1 wherein the medical device is made with a polymer.