Drug – bio-affecting and body treating compositions – Solid synthetic organic polymer as designated organic active...
Reexamination Certificate
2000-12-18
2003-11-11
Woodward, Ana (Department: 1711)
Drug, bio-affecting and body treating compositions
Solid synthetic organic polymer as designated organic active...
C424S078310, C424S078320, C424S078350, C424S078360, C424S078370, C424S078380, C523S112000, C523S122000, C427S405000
Reexamination Certificate
active
06645483
ABSTRACT:
BACKGROUND
1. Technical Field
The present invention relates to a lubricant coating for medical devices, and more particularly, to a hydrophilic polymeric coating which aids medical devices to become slippery when wetted. The lubricant coating of the present invention may be employed to reduce the coefficient of friction of catheters, arterial venous shunts, gastroenteric feed tubes, endotracheal tubes and other medical implants or polymeric substrates. The coating of the present invention also incorporates additive compounds such as anti-microbial that are released in a pharmaceutically acceptable manner. Methods are also provided for the manufacture of the subject lubricant coating and for the application of the same to surfaces of medical devices.
2. Background of the Related Art
Known lubricant coatings applied to surfaces of medical devices include coatings of polyvinylpyrrolidone, polyurethane, acrylic polyester, vinyl resin, fluorocarbons, silicone rubber, and combinations of these substances. For example, Micklus et al., U.S. Pat. Nos. 4,100,309 and 4,119,094, relate to a hydrophilic coating of polyvinylpyrrolidone-polyurethane interpolymer formed using polyisocyanate. Ratner et al., U.S. Pat. No. 3,939,049, relates to a method of grafting hydrogels for lubrication to polymeric substrates using radiation. Hungton et al., U.S. Pat. No. 3,975,350, relates to hydrophilic polyurethane polymers for use as lubricants. Storey. et al. U.S. Pat. No. 3,987,497, relates to a tendon prosthesis having a lubricant hydrogel coating. Many known lubricious coatings are prone to various disadvantages when used in the medical field. Disadvantages of such known lubricants may include insufficiently low coefficient of friction, lack of permanence such as characteristic of silicone or fluorocarbon based coatings, slipperiness when dry as well as wet thus making handling difficult, utilization of hazardous solvents in the manufacture of the same and utilization of unstable reactive materials in the manufacture of the same. Lubricants produced for medical use from unstable reactive material often require the coating solution to be prepared daily or more frequently to be useful and thereby increases waste and expense. Lubricants produced for medical use involving hazardous solvents are undesirable due to patient toxicity concerns and OSHA considerations. Also, lubricant coatings provided for inducing foreign devices into various areas of the body that are susceptible to infection and or thrombogenic reactions have failed to provide a pharmaceutically acceptable carrier for anti-microbial and anti-thrombogenic compounds.
In order to solve these and other potential disadvantages of known lubricants such as those of the above-cited patents incorporated herein by reference, a lubricant coating is needed which when wetted has sufficient lubricity to be useful in the medical device field such as for medical implants and the ability to incorporate within that coating anti-microbial compounds that can be released in a pharmaceutically acceptable manner. The lubricant coating must be capable of adhering to a wide variety of substrates and resist wet abrasion. It would also be desirable to have such a lubricant coating prepared from chemically stable and biocompatible solvents.
SUMMARY OF THE INVENTION
The present invention provides a lubricant coating composition comprising a hydrophilic polymer comprising polyvinylpyrrolidone, polyoxyethylene-based isocyanate-terminated prepolymer, ethyl lactate and toluene. The present invention also provides a method of making the subject lubricant coating which adheres to a wide variety of substrates and resists wet abrasion. The subject lubricant coating is chemically stable and is bio-compatible as described in greater detail below.
A method for using the subject lubricant coating composition to coat medical devices is provided herein which involves cleaning or washing, drying, dip coating or applying of the lubricant, air drying or removal of excess lubricant, optionally baking and packaging a medical device either before or after sterilization thereof.
The present invention also provides a medical device whereby at least a portion thereof is coated with the subject lubricant coating which is characterized as being able to achieve a wetted lubricity with a reduction of friction of more than fifty (50) percent.
The present invention also provides a vehicle for incorporating an anti-microbial or anti-thrombogenic agent having pharmaceutically acceptable pharmacokinetic properties without interfering with the lubricous nature of the coating.
DETAILED DESCRIPTION OF THE INVENTION
The lubricant coating of the present invention has been found particularly useful in lowering the coefficient of friction of medical devices such as indwelling thoracic catheters and other medical devices. The subject coating is manufactured from a blend of one or more C1-12 alkylbenzenes such as, for example, toluene, xylene, or styrene but preferably toluene to increase stability, a C1-12 alkylester of a carboxylic acid such as for example, ethyl lactate, methylbenzoate, or propolyacrylate wherein ethyl lactate is preferred to increase stability, a polymer such as for example polyvinylpyrrolidone, polyvinyl alcohol, polyacrylic acid or polyethylene oxide, but preferably polyvinylpyrrolidone to increase hydrophilicity and lubricity, and an isocyanate-terminated prepolymer such as, for example, polyoxyethylene-based isocyanate such as a toluene or isophorone diisocyanate-based prepolymer such as for example Hypol* PreMA G60 manufactured by Hampshire Corporation, Lexington, Mass., or Vibrathane® a 4,4-diphenylmethane-disocyanante (MDI) an urethane prepolymer manufactured by Uniroyal, or Pellethane an aromatic ether polyurethane manufactured by Dow Chemical, or Hyrothane manufactured by CardioTech international and or Adiprene® a low-free TDI manufactured by Uniroyal Chemical.
The urethane increases the binding strength of the coating and controls the rate of release and thus enables the pharmacokinetics of the anti-microbial or other pharmacological additive to be within acceptable pharmaceutical limits and it covalently binds anti-thrombogenic additives to prevent systematic absorption. While different urethanes have different properties and may require different solvent systems, the durometer of the urethane must match the durometer of the medical device to be coated or the functionality of the medical device may become compromised. Solvent selection and blend ration are important to provide adequate solubility and inertness to the hydrophilic urethane and additives. Anti-microbials additives, such as silver salts or antibiotics, may be uniformly suspended within the coating solution. These additives are released on contact with moisture, the rate of release and the lubricious properties of the coating are controlled by altering the ratio of urethane and PVP For further examples of suitable polyisocyanates see Encyclopedia of Polymer Science and Technology, H. F. Mark, N. G. Gaylord and N. M. Bikeles (eds.) (1969) incorporated herein by reference.
Anti-microbial additives utilized within this present invention include the biguanides, especially chlorhexidine and its salts, including chorhexidene acetate, chlorhexideine gluconate, chlorhexidine hydrochloride, and chlorhexidine sulfate, silver and its salts, including silver acetate, silver benzoate, silvercarbonate, silver iodate, silver iodide, silver lactate, silver laurate, silver nitrate, silver oxide, silver palmitate, silver protein, and silver sulfadiazine, polymyxin, tetracycline, aminoglycosides, such as tobramycin and gentamicin, rifampician, bacitracin, neomycin, chloramphenical, miconazole, tolnaftate,quinolone such as oxolinic acid, norfloxacin, nalidix acid, pefloxacin, enoxacin and ciprofloxacin, penicillins such as ampicillin, amoxicillin and piracil, cephalosporins, vancomycin, and combinations of any of the above anti-microbials.
An anti-thrombromgenic additive useful according to this present invention would be heparin. A
Brown Rudnick Berlack & Israels LLP
Leonardo Mark S.
Serio John C.
Sherwood Services AG
Woodward Ana
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