Biomedical devices with amid-containing coatings

Details Biomedical devices with amid-containing coatings Biomedical devices with amid-containing coatings

1999-06-09

2002-12-31

Szekely, Peter (Department: 1714)

Coating processes

Medical or dental purpose product; parts; subcombinations;...

Implantable permanent prosthesis

C427S164000, C427S165000, C428S411100, C351S16000R, C523S106000, C523S107000, C523S108000, C264S001700

Reexamination Certificate

active

06500481

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to biomedical devices. In particular, the invention provides biomedical devices on the surfaces of which stable, hydrophilic, amide-containing coatings are formed.
BACKGROUND OF THE INVENTION
Devices for use in and on the human body are well known. The chemical composition of the surfaces of such devices plays a pivotal role in dictating the overall efficacy of the devices. For example, many devices, including catheters, stents, lenses, and implants require biologically non-fouling surfaces, meaning that proteins, lipids, and cells will not adhere to the surfaces. Lenses also must be wettable by tear fluid in order to ensure wearer comfort. Additionally, providing such devices with an antimicrobial surface is advantageous.
A wide variety of methods have been developed to coat device surfaces to provide them with desired characteristics. However, the need still exists for a simple, efficient process that will provide a stable, hydrophilic coating.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
The present invention provides a simple, economical process for producing devices with stable amide group-containing coatings including, without limitation, polyacrylamide coatings. In one embodiment, the invention provides a method for manufacturing biomedical devices comprising, consisting essentially of, and consisting of contacting at least one surface of a biomedical device, the surface comprising, consisting essentially of, and consisting of an effective amount of carboxyl groups with a coating-effective amount of an amine and a coupling effective amount of at least one coupling agent under conditions suitable to produce a stable, amide-containing coating on the surface. In another embodiment, the invention provides biomedical devices comprising, consisting essentially of, and consisting of a biomedical device at least one surface of the device having an amide-containing coating coupled thereto by at least one coupling agent.
By “biomedical device” is meant any device designed to be used while in or on either or both human tissue or fluid. Examples of such devices include, without limitation, stents, implants, catheters, and ophthalmic lenses. In a preferred embodiment, the biomedical device is an ophthalmic lens including, without limitation, contact or intraocular lenses. More preferably, the device is a contact lens.
It is an unexpected discovery of the invention that devices having carboxyl groups on their surfaces may be contacted with an amine to provide a hydrophilic, amide-containing coating for biomedical devices. It is another unexpected discovery of the invention that a high conversion of carboxyl groups to amide groups is obtained through the process of the invention. More specifically, a conversion of greater than about 80 percent, more preferably greater than about 90 percent, most preferably about 95 percent or greater, of the carboxyl groups to amide groups may be obtained. The carboxyl groups must be present in an amount effective to produce the desired number of amide groups when reacted with an amine. This amount is an amount of carboxyl groups per square centimeter of lens surface of about 0.65 to about 65 nMol/cm
2
, preferably about 1 to about 50, more preferably about 1 to about 10 nMol/cm
2
of carboxyl groups.
In the process of the invention, a coating-effective amount of an amine is used, which amount is sufficient to convert the carboxyl groups present to the desired degree. The amine may be used as a part of a solution containing a solvent, such as an alcohol, tetrahydrofuran, or the like, or an aqueous solution. Preferably, an aqueous solution is used. The amount of amine in the solution may be about 5 volume percent, preferably about 1 volume percent, more preferably less than about 1 volume percent. The coatings produced by the process of the invention are stable, meaning that subjecting the coating to autoclaving, washing with a cleaning agent, and/or rinsing with a saline solution does not substantially alter the chemical properties of the coating.
A coupling effective amount of the coupling agent is used which amount is sufficient to enable to reaction of the carboxyl groups with the amine. The precise amount of coupling agent used will depend on the surface's chemistry as well as the amine and coupling agent selected. The amount of coupling agent used generally will be about 0.01 to about 25 weight percent, preferably about 0.1 to about 15, more preferably, about 0.1 to about 10 weight percent of the coating solution, or solvent, coupling agent and optional buffer. Suitable solvents are those capable of solubilizing both the amine and the coupling agent. Preferably, the process is carried out in a water, or aqueous, solution.
The contacting time typically may be about 1 to about 360 minutes, preferably 1 to about 240 minutes. The contacting temperature may be about 0 to about 95, preferably about 5 to about 80° C. The contacting, or reacting, of the amine and carboxyl groups may be carried out in any convenient manner.
Amines useful in the invention are any primary or secondary amines, their corresponding acid salts, amine-containing proteins, amine-containing antibiotics, and the like, and combinations thereof Examples of useful amines, proteins, and amine-containing antibiotics include, without limitation., ammonium chloride, glucosamine hydrochloride, dimethylamine hydrochloride, ethanolamine hydrochloride, diethanolamine hydrochloride, polyethylene glycol amines such as hexa(ethyleneglycol)-bis-amine, lactoferrin, lysozyme, albumin, casein, cytochrome C, immunoglobulins, avidin, heparin, polymyxin, and the like, and combinations thereof.
Coupling agents useful in the invention include any coupling agent capable of enabling the reaction of a carboxyl group with an amine group to form an amide. Useful suitable classes of coupling agents include, without limitation, dehydrating agents such as carbodiimides, acid halides of inorganic or organic acids, isocyanides, and the like, and combinations thereof Examples of suitable coupling agents include, without limitation, carbodimides, N,N′-carbonyldiimidazole, phosphoryl chloride, titanium tetrachloride, sulfuryl chloride fluoride, chlorosulfonyl isocyanate, phosphorus iodide, pyridinium salts of tributyl amine, phenyl dichlorophosphate, polyphosphate ester, chlorosilanes, and the like as well as mixtures of tributyl phosphorus and phenyl isocyanate, alkyl chloroformates and triethyl amine, 2-chloro-1,3,5-trinitrobenzene and pyridine, methyl sulfuryl chloride and diethyl amine, and triphenylphosphine, carbon tetrachloride and triethyl amine. Preferred coupling agents are carbodiimides. More preferred are 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and dicyclohexyl carbodiimide.
The devices used for purposes of the invention may be made of one or more carboxyl functional hydrophilic polymers. Alternatively, one or more surfaces of a device may be coated with one or more carboxyl functional polymers. Thus, in yet another embodiment, the invention provides a method for manufacturing biomedical devices comprising, consisting essentially of, and consisting of coating at least one surface of a device with one or more carboxyl functional polymers, subsequently contacting the at least one surface with a coating-effective amount of an amine and a coupling effective amount of at least one coupling agent under conditions suitable to produce a stable, amide-containing coating on the surface.
Examples of suitable carboxyl functional hydrophilic polymers include, without limitation, poly(acrylic acid), poly(methacrylic acid), poly(maleic acid), poly(itaconic acid), block or random copolymers of (meth)acrylic acid, acrylic acid, maleic acid, itaconic acid with any reactive vinyl monomer, carboxymethylated polymers, such as carboxymethylcellulose, and the like, and mixtures thereof. Preferably, the carboxyl functional hydrophilic polymer is poly(acrylic acid) or poly(methacrylic acid). More preferably, poly(acrylic acid) is used.
The carboxy

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