Drug-eluting medical implants
Inventors
Palasis, Maria • You, Changcheng • Concagh, Danny • Core, Lee • Ho, Kicherl • Sharma, Upma • Zugates, Gregory T.
Assignees
Arsenal Medical Inc • Lyra Therapeutics Inc
Publication Number
US-9737647-B2
Publication Date
2017-08-22
Expiration Date
2030-05-19
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Abstract
Disclosed are self-expanding medical implants for placement within a lumen of a patient. The implants comprise a woven or non-woven structure having a substantially tubular configuration, and are designed to be low-profile such that they are deliverable with a small diameter catheter. The implants have a high recoverability and desired mechanical properties.
Core Innovation
The invention provides self-expanding medical implants for placement within a lumen or cavity of a patient. These implants consist of a woven or non-woven substantially tubular structure made from polymeric or metallic strands, and are designed to be low-profile, allowing delivery through small diameter catheters. The devices are further characterized by high recoverability and mechanical properties such as expansion characteristics and strength sufficient for use in various bodily lumens or cavities.
The implants may include polymeric strands and incorporate a therapeutic agent, such as paclitaxel, with the quantity specifically within the range of about 0.002 to about 0.175 micrograms per square millimeter of surface area. The design seeks to address previous limitations in non-metallic, low-profile stents, specifically poor expandability, inadequate radial strength, and difficulty in controlling degradation rates and drug elution. The coating and strand materials are selected and configured to optimize mechanical properties, allow desired drug release kinetics, and enable full absorption of the implant within a specified timeframe.
The problem addressed includes the shortcomings of metallic and polymeric stents, such as the risks of thrombosis, restenosis, poor mechanical properties in polymer-based devices, and unmanageable drug release profiles. The innovation includes the use of specific biodegradable materials with elastic modulus between 1 and 10 GPa, optimized strand geometries, and controlled drug loading and release properties, aiming for sufficient expansion, mechanical strength, and clinically effective but reduced drug dosing.
Claims Coverage
There are two independent claims describing two inventive features for medical implants.
Tubular structure with polymeric strands, conformal paclitaxel coating, and controlled drug amount
A medical implant comprising: - A tubular structure of polymeric strands with open spaces between adjacent strands, where the strands are made from a first biodegradable material (fully absorbed within a patient, elastic modulus 1–10 GPa). - At least one conformal coating partially or fully coating the polymeric strands, the coating comprising paclitaxel and a second biodegradable material (also fully absorbed within a patient). - The tubular structure has a defined surface area, with the paclitaxel amount controlled within the range of about 0.002 to about 0.175 micrograms per square millimeter of the surface area.
Tubular structure with polymeric strands of different diameters and conformal paclitaxel coating
A medical implant comprising: - A tubular structure with polymeric strands and open spaces, including a first set of strands of one cross-sectional diameter and a second set of strands of a different cross-sectional diameter. - Both strand sets are made from biodegradable material fully absorbed within the patient. - At least one conformal coating at least partially coating the strand sets, with the coating comprising paclitaxel and a second biodegradable material (fully absorbed within the patient). - The tubular structure characterized by a surface area, with the paclitaxel amount within about 0.002 to about 0.175 micrograms per square millimeter of surface area.
The claims broadly cover biodegradable, tubular, self-expanding implants with precisely controlled drug content, strand configuration, and material selection, including options for multiple strand diameters, with paclitaxel elution for clinical use.
Stated Advantages
The implants have high recoverability and are able to recover to an exceptionally high percentage of their manufactured diameter after being crimped.
They exhibit improved strength and resistance to deformation by radial forces compared to conventional polymeric and metallic stents.
They are low-profile, making them deliverable via small diameter catheters into small-diameter bodily lumens.
The implants utilize a relatively small quantity of therapeutic agent yet provide favorable preclinical results.
Reduced drug loading can minimize manufacturing costs and decrease the risk of unintended effects in tissues adjacent to the treatment site.
The implants achieve predictable and reproducible drug (paclitaxel) elution profiles, with complete drug release within a defined timeframe.
Documented Applications
Implantation into vascular lumens, including coronary arteries and peripheral arteries such as the superficial femoral artery.
Implantation for treatment of vascular aneurysms through woven grafts and stent-grafts.
Use as polymeric tubes and catheters to bypass strictures in the ureter and urethra.
Stenting in peripheral vasculature, prostate, sinus, and esophagus, including use as esophageal scaffolds.
Deployment into other small diameter lumens such as biliary, uro-genital, iliac, and tracheal-bronchial anatomy.
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