Stent assembly and method of preparing the stent assembly

1. A stent assembly consisting of:

a stent, wherein the stent is a tube or a helical coil;

a first carrier comprising a first active agent, wherein the first carrier is disposed as one or more layers on at least a portion of an exterior surface of the stent; and

a swellable coating comprising a second active agent, wherein the swellable coating further comprises a second carrier comprising a third active agent, wherein the second carrier is in a form of particles, wherein the swellable coating is disposed on at least a portion of the one or more layers of the first carrier, wherein the swellable coating swells by 5 times to 160 times its volume under urinary conditions to make contact with a ureter wall of a subject.

2. The stent assembly according to claim 1 , wherein the swellable coating comprises a swellable material selected from the group consisting of a hydrogel, a water swellable polymer, a superabsorbent polymer, copolymers of the water swellable polymer and the superabsorbent polymer, and combinations thereof.

3. The stent assembly according to claim 1 , wherein the first, second and third active agents are independently selected from the group consisting of an antifibrotic agent, an anticancer agent, a discomfort reducing agent, an antibacterial agent, a gene, a gene vector, a growth factor, and combinations thereof.

4. The stent assembly according to claim 1 , wherein amount of the first active agent in the first carrier is in the range of about 2 wt % to about 25 wt % of the carrier.

5. The stent assembly according to claim 1 , wherein the one or more layers has a thickness in the range of about 10 μm to about 1000 μm.

6. The stent assembly according to claim 1 , wherein the one or more layers comprises a thermoplastic elastomer.

7. A method of preparing a stent assembly of claim 1 , the method comprising:

providing a stent, wherein the stent is a tube or a helical coil;

disposing a swellable coating on the stent, wherein the swellable coating is adapted to swell by 5 times to 160 times its volume under urinary conditions to make contact with a ureter wall of a subject; and

disposing a first carrier on at least a portion of an exterior surface of the stent,

wherein the first carrier comprises a first active agent, and

wherein the swellable coating comprises a swellable material and a second active agent, the swellable coating further comprises a second carrier comprising a third active agent, the second carrier being in a form of particles.

8. The method according to claim 7 , wherein providing the stent comprises physically treating the exterior surface of the stent by etching, and/or roughening the exterior surface with solid particles.

9. The method according to claim 7 , wherein providing the stent comprises chemically treating the exterior surface of the stent with plasma treatment.

10. The method according to claim 7 , wherein disposing the swellable coating on the stent comprises applying a liquid reagent comprising the swellable material and the second active agent on at least the portion of the exterior surface of the stent.

11. The method according to claim 7 , wherein disposing the first carrier comprises dispersing the first carrier on the exterior surface of the stent.

12. The method according to claim 7 , wherein the swellable material comprises a hydrogel.

13. The method according to claim 12 , wherein disposing the swellable coating on the stent further comprises cross-linking a hydrogel-forming agent to form the hydrogel.

14. The method according to claim 13 , wherein the swellable material further comprises a photoinitiator.