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EP-4740991-A2 - ACTIVE AGENT COATING FOR BALLOONS OF BALLOON CATHETERS

EP4740991A2EP 4740991 A2EP4740991 A2EP 4740991A2EP-4740991-A2

Abstract

The invention relates to a method for coating the surface of a balloon catheter with an active ingredient, wherein the balloon is made of an elastic material and is expandable by pressurizing it with a fluid, and wherein the balloon is designed to be expanded at a target location, the coating of the balloon's surface being carried out at a pressure lower than the pressure applied to expand the balloon at the target location. In this way, due to the generation of shear forces, a particularly effective delivery of the active ingredient from the balloon to the inner wall of the blood vessel or the surrounding tissue is achieved. The invention further relates to a corresponding balloon and a balloon catheter.

Inventors

  • RUEBBEN, ALEXANDER

Assignees

  • Ruebben, Alexander

Dates

Publication Date
20260513
Application Date
20190911

Claims (13)

  1. Method for coating the surface of the balloon of a balloon catheter with an active ingredient, wherein the balloon is made of an elastic material and is expandable by pressurizing it with a fluid, wherein the balloon is intended to be expanded at a target location, and the coating of the surface of the balloon is carried out at a pressure which is below the pressure which is applied to expand the balloon at the target location. characterized by that at least the part of the balloon's surface coated with the active ingredient is wetted with a liquid containing water and/or at least one alcohol, and that the balloon's surface area is at least 10% larger at the target location during expansion than during coating.
  2. Method according to claim 1, characterized in that the pressure at which the coating is carried out is at least 20%, preferably at least 30%, below the pressure applied for the expansion of the balloon at the destination.
  3. Method according to claim 2, characterized in that the pressure at which the coating is applied is a maximum of 50% of the pressure applied for the expansion of the balloon at the destination.
  4. Method according to one of claims 1 to 3, characterized in that the elastic material comprises a polyurethane, a polyolefin copolymer, a polyethylene or a silicone.
  5. Method according to one of claims 1 to 3, characterized in that the elastic material comprises a thermoplastic elastomer, in particular a polyether block amide.
  6. Method according to one of claims 1 to 5, characterized in that the surface area of the balloon during expansion at the destination is at least 20%, preferably at least 30%, more preferably at least 40% and very preferably at least 50% larger than during coating.
  7. Method according to any one of claims 1 to 6, characterized in that the active ingredient used is selected from the group consisting of: tretinoin, orphan receptor agonists, elain derivatives, corticosteroids, steroid hormones, paclitaxel, rapamycin, tacrolimus, hydrophobic proteins, heparin and/or hormone-like or cell proliferation-altering substances.
  8. Method according to one of claims 1 to 7, characterized in that at least the part of the surface of the balloon coated with the active ingredient is coated with a polysaccharide before or after coating with the active ingredient.
  9. The method according to claim 8, characterized in that the average molar mass of the polysaccharide is 10,000 to 100,000,000 Da.
  10. The method according to claim 9, characterized in that the mean molar mass of the polysaccharide is 20,000 to 80,000 Da.
  11. Method according to one of claims 8 to 10, characterized in that the polysaccharide is a dextran.
  12. Balloon of a balloon catheter, the surface of which has at least a partial coating with an active ingredient, obtainable by a method according to any one of claims 1 to 11.
  13. Balloon catheter comprising a balloon according to claim 12.

Description

The invention relates to a method for coating the surface of the balloon of a balloon catheter with an active ingredient, wherein the balloon is made of an elastic material and is expandable by pressurizing it with a fluid, and wherein the balloon is intended to be expanded at a target location. So-called "minimally invasive procedures" are playing an increasingly important role in medicine. Percutaneous transluminal angioplasty (PTA) using balloon dilation is frequently employed to treat vascular constrictions such as arteriosclerosis. In this procedure, a balloon catheter, which has a fluid-expandable balloon at its distal end, is guided to the stenosis (narrowing of the blood vessel) using a guide catheter. There, the balloon is inflated, forcing blood flow-inhibiting deposits onto or into the vessel wall, thus restoring unimpeded blood flow. After the treatment is complete and the balloon is subsequently deflated, the balloon catheter is withdrawn from the vascular system and removed. In some cases, a restenosis can occur in the treated vessel segment following an initially successful angioplasty. This restenosis is usually due to cell proliferation in the affected vessel segment; that is, blood vessel cells grow into the vessel lumen and again obstruct blood flow. To prevent this, medications are increasingly being used. Coated balloon catheters are used. The corresponding medications usually have an antiproliferative effect, particularly on smooth muscle cells (SMCs), and are intended to prevent restenosis caused by excessive growth of these cells. The medication is located on the outside of the balloon and is transferred from the balloon to or into the inner wall of the vessel during balloon dilation. Typically, the balloon of the balloon catheter is coated by applying an active ingredient dissolved in a solvent to the surface of the balloon, with the solvent evaporating after application. The active ingredient then forms a layer on the surface and can be administered during balloon dilation. The transfer of the drug from the balloon's surface to the vessel wall has proven problematic. It is crucial to consider that balloon expansion must be strictly time-limited, as prolonged occlusion of the blood vessel would cause ischemia and an insufficient blood supply to tissues or organs, potentially leading to infarction. Accordingly, drug delivery must occur within a relatively short timeframe. In the coronary artery, the balloon can be expanded for a maximum of 30 to 60 seconds. However, existing drug-coated balloons often require a longer period for sufficient drug delivery. This leads either to the aforementioned ischemic problems or to insufficient drug delivery due to the necessary shortening of the balloon expansion time. Furthermore, it must be ensured that the active ingredient only detaches from the balloon surface at the target site, especially since the active ingredients used are often toxic substances such as paclitaxel, where release away from the target site is undesirable. In addition, the safety of the medical personnel administering the treatment must be guaranteed. This creates a conflict of objectives: on the one hand, the active ingredient or medication must be delivered as quickly as possible at the target site and transferred to the inner wall of the blood vessel; on the other hand, the active ingredient should be protected during preparation and advancement of the balloon. The balloon catheter should adhere firmly to the balloon. However, the delivery of a highly adhesive drug usually occurs slowly. The challenge, therefore, is to provide a balloon that, on the one hand, securely holds the active ingredient coating, but on the other hand, rapidly releases the active ingredient upon expansion at the target location. This problem is solved according to the invention by a method for coating the surface of the balloon of a balloon catheter with an active ingredient, wherein the balloon is made of an elastic material and is expandable by pressurizing it with a fluid, wherein the balloon is intended to be expanded at a target location, wherein the coating of the surface of the balloon takes place at a pressure that is below the pressure that is applied for the expansion of the balloon at the target location. Balloons for balloon catheters are generally classified as non-compliant, semi-compliant, and compliant. The difference lies in the varying degree of diameter increase when the balloon is filled with a fluid under a specific pressure. Compliance is defined as follows: Compliance (in %) = (d (high pressure) - d (low pressure))/d (low pressure) × 100 %, where d is the diameter of the balloon. The high and low pressures can be considered the endpoints of the so-called working range, where the working range extends between the nominal pressure at which the balloon reaches its nominal diameter and the maximum pressure to which the balloon can be inflated without damage. Depending on the