Pre-dried drug delivery coating for use with a stent

Abstract

A method and apparatus for the provision of a coating for application to a medical device results in a medical device having a bio-absorbable coating. The coating includes a bio-absorbable carrier component. In addition to the bio-absorbable carrier component, a therapeutic agent component and solvent can also be provided. The solvent is removed from the coating before the coating is applied to the medical device. The coated medical device is implantable in a patient to effect controlled delivery of the coating, including the therapeutic agent, to the patient.

Description

RELATED APPLICATION [0001] This application claims priority to, and the benefit of, co-pending U.S. Provisional Application No. 60 / 613745, filed Sep. 28, 2004, for all subject matter common to both applications. The disclosure of said provisional application is hereby incorporated herein by reference in its entirety. This application also relates to co-pending U.S. patent application Ser. No. 10 / ______ (Attorney Docket No. ATA-426), filed concurrently with this application on September 28, 2005. FIELD OF THE INVENTION [0002] The present invention relates to coatings suitable for application to medical devices for delivery of one or more biologically active agents, and more particularly to a bio-absorbable coating in which solvent is removed before the coating material is applied to the medical devices, and an apparatus and method for removing solvent from the coating material. BACKGROUND OF THE INVENTION [0003] Therapeutic agents may be delivered to a targeted location in a human ut...

AI Technical Summary

Benefits of technology

[0042] In accordance with further aspects of the present invention, the surface of the medical device can be provided with a surface preparation prior to the application of the coating comprising the bio-absorbable carrier component. The pre-treatment, or preparation of the surface, improves coating conformability and consistency and enhances the adhesion of the coating comprising the bio-absorbable carrier component. The pre-treatment can be bio-absorbable, and can contain lipids. The pre-treatment can be a naturally occurring oil, such as fish oil, and can be modified from its naturally occurring state to state of increased viscosity in the form of a cross-linked gel. The pre-treatment can contain omega-3 fatty acids. The pre-treatment can contain a drug.

[0047] The method can further provide a compatibilizer, such as vitamin E or its derivatives, which also acts as a stabilizer and preservative during formation of the coating.

[0049] In accordance with further aspects of the present invention, the method can further include providing a surface preparation or pre-treatment on the surface of the medical device prior to application of the coating comprising the bio-absorbable carrier component, wherein the pre-treatment improves the coating consistency and conformability and enhances the adhesion of the coating comprising the bio-absorbable carrier component. The pre-treatment can be bio-absorbable, contain lipids, and / or take the form of a naturally occurring oil, such as fish oil. The pre-treatment can be modified from its natural state to a state of increased viscosity in the form of a cross-linked gel. The pre-treatment can contain a therapeutic agent. The pre-treatment can contain reactive oils.

[0052] In addition, methods can be used to enhance the curing process. These methods include, for example, the addition of other reactive oils, such as linseed oil, and the application of reactive gasses, such as oxygen, fluorine, methane or propylene, plasma treatment, and pressure in the presence of reactive gasses and the like.

[0055] The apparatus can also include a mechanism for agitating, mixing, stirring or otherwise replenishing the surface of coating substance to increases the rate of solvent evaporation. The mechanism accelerates the transfer of solvent to the surrounding environment. For example, the apparatus can include a rotating fixture containing the coating material. By rotating the fixture, it can continuously disturb and refresh the surface of the coating material in the fixture, and hence increase the drying rate of the coating material in the fixture.

Problems solved by technology

However, there are drawbacks to systemic delivery of a therapeutic agent, one of which is that high concentrations of the therapeutic agent travels to all portions of the patient's body and can have undesired effects at areas not targeted for treatment by the therapeutic agent.

Furthermore, large doses of the therapeutic agent only amplify the undesired effects at non-target areas.

There is no discussion of any therapeutic benefit inherent in the silicone fluid itself, and there is no suggestion that other oils can be utilized to control the delivery of the antimicrobial agent

Although the '830 publication attempts to discuss every possible combination of delivery coating in combination with every drug or therapeutic agent that may have some utility in targeted delivery applications, there is no realization of the difficulty of using an oil for the controlled release of a therapeutic agent in a long term application.

A list of potential delivery vehicles identifies waxes and fats, however there is no indication that such vehicles can be utilized for anything other than a short term drug delivery.

However, there is no indication in the application as to how a slow controlled release of ozone can be affected.

There is no enablement to a long term controlled release of ozone from the olive oil gel, however, there is mention of use of biocompatible polymers to form the coating that holds and releases the ozone.

It further states that such coatings are not necessarily satisfactory in all cases because they tend to run off and lose the initial lubricity rather rapidly and they can also lack abrasion resistance.

At the end of the period, it was observed that the bare stents and polymer coated stents resulted in some minor inflammation of the tissue.

Preferences were discussed for the use of oils rather than waxes or solids, and the operations performed on the fat or oil as described can be detrimental to the therapeutic characteristics of some oils, especially polyunsaturated oils containing omega-3 fatty acids.

However, there is no realization of the difficulty of using an oil for the controlled release of a therapeutic agent in a long term application.

Images