Drug-releasing coatings for medical devices
First Claim
1. A medical device having at least a portion which is insertable or implantable into the body of a patient, wherein the portion has a surface which is adapted for exposure to body tissue of the patient and wherein at least a part of the surface is covered with a coating for release of at least one biologically active material, the coating comprising an internal reservoir layer and an outer layer in contact with the reservoir layer;
- wherein the outer layer comprises an ionic surfactant complexed to the biologically active material; and
wherein the reservoir layer comprises a polymer incorporating the biologically active material which is substantially free of any ionic surfactant such that the biologically active material of the reservoir layer can migrate outwardly from the reservoir layer, and at least some of the biologically active material of the reservoir can complex with the ionic surfactant in the outer layer as the biologically active material releases from the outer layer.
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Accused Products
Abstract
The invention is directed to medical devices having a drug-releasing coating and methods for making such coated devices. The coating permits timed or prolonged pharmacological activity on the surface of medical devices through a reservoir concept. Specifically, the coating comprises at least two layers: an outer layer containing at least one drug-ionic surfactant complex overlying a reservoir layer containing a polymer and the drug which is substantially free of an ionic surfactant. Upon exposure to body tissue of a medical device covered with such coating, the ionically bound drug in the outer layer is released into body fluid or tissue. Following release of such bound drug, the ionic surfactant binding sites in the outer layer are left vacant. To maintain the pharmacological activity after delivery of the ionically bound drug, additional amounts of the drug are embedded or incorporated in the reservoir layer in a manner which allows the drug, which is substantially free of ionic surfactants, to complex with the vacant binding sites of the ionic surfactant of the outer layer. As a result, the surface of the medical device is enriched with the drug to provide sustained pharmacological activity to prevent the adverse reaction due to the presence of the medical device. The invention is further directed to medical devices with stabilized drug-releasing coatings. The coatings are stabilized by exposure to a low energy, relatively non-penetrating energy source, e.g., gas plasma or an electron beam energy source.
470 Citations
19 Claims
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1. A medical device having at least a portion which is insertable or implantable into the body of a patient, wherein the portion has a surface which is adapted for exposure to body tissue of the patient and wherein at least a part of the surface is covered with a coating for release of at least one biologically active material, the coating comprising an internal reservoir layer and an outer layer in contact with the reservoir layer;
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wherein the outer layer comprises an ionic surfactant complexed to the biologically active material; and wherein the reservoir layer comprises a polymer incorporating the biologically active material which is substantially free of any ionic surfactant such that the biologically active material of the reservoir layer can migrate outwardly from the reservoir layer, and at least some of the biologically active material of the reservoir can complex with the ionic surfactant in the outer layer as the biologically active material releases from the outer layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification