Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
1998-03-05
2002-12-31
Lewis, Kim M. (Department: 3761)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C602S041000, C602S054000
Reexamination Certificate
active
06500539
ABSTRACT:
FIELD OF THE INVENTION
The invention is directed to a cellulose acetate anti-adhesion wound pad or dressing, and in particular to a cellulose acetate anti-adhesion pad having a low level of siloxane finishing agent applied thereto. The pad has use in the medical arts area for application to wounds, particularly burns.
BACKGROUND OF THE INVENTION
Numerous injuries, and particularly burns, require the application of some type of pad, gauze, cloth, dressing or similar covering (herein collectively called a “dressing”) to protect the wound while it is healing. Wounds, especially burns, sometimes have difficulty in healing and are frequently prone to infection because natural protective skin barriers are disrupted and are slow in repairing themselves. The most commonly used dressing material has been cotton because it is both inexpensive and readily available. However, as those who have used cotton dressings are aware, they tend to stick to the injured area, even when the surface of the area is covered with a lubricant such as petroleum jelly (“petrolatum”) or similar substance, or a medicinal which contains a lubricant. Developments in the medical arts have resulted in some improvements in medical dressings, two of which are represented by Johnson & Johnson's ADAPCTIC™ brand non-adherent dressings and the Curity® brand TELFA® sterile pads sold by Kendall-Futuro Company. The ADAPTIC™ brand dressing was found to consist of a cellulose acetate pad which has been soaked in petrolatum or similar substance to impart anti-adhesion properties. While the petrolatum reduces adhesion to a wound, it's use results in a pad that is greasy and messy to handle compared to a pad without petrolatum. The TELFA® dressing consists of a polyethylene terephthalate (PET) shell and a caustic washed cotton insert, the anti-adhesion properties being imparted by the PET shell.
Another dressing is disclosed in China Patent No. CN 87 1 01823 A, published Aug. 31, 1988, to Tie Han et al. This Chinese patent describes a “Medicinal Anti-Adhesive Dressing” prepared using plain cellulose acetate to make a spun and woven gauze, or a nonwoven fabric having a weight of 50-80 g/m
2
. No additional information is given concerning treatment of the cellulose acetate material before, during or after preparation of the dressing. The dressing did not contain a biostat nor was use of a biostat suggested.
United States patents disclosing the use of cellulosic materials and siloxane materials in wound dressing include:
U.S. Pat. No. 5,372,739 to B. Shriram which describes fibers, including cellulose acetate fibers, having polyethylene glycol fatty acids thereon to reduce adhesion;
U.S. Pat. No. 4,984,570 to Langen et al. which describes a wound dressing having a cellulose acetate absorbent pad and a hydrophobic man-made fiber covering over the pad which covering is in contact with the wound;
U.S. Pat. No. 4,546,027 to Holvoet which describes the use of a nonwoven corrugated fabric for medical and surgical compresses, which compresses include the use of plastic reinforced cellulose fibers;
U.S. Pat. No. 5,635,201 to Fabo which describes the use of a curable siloxane material coated on a carrier surface and heat cured to form a siloxane gel; and
U.S. Pat. No. 5,685,832 to Chen et al. which describes a wound dressing comprising a woven cellulose acetate substrate and a partial solvent thereon, which dressing releases, in a controlled manner, acetic acid to act as a therapeutic agent.
U.S. Pat. No. 3,285,245 to Eldridge et al. which describes an absorbent wound dressing having an absorbent backing and a non-absorbent facing.
These dressing, while having various qualities which may reduce adhesion or provide other benefits, incorporate lubricants and/or fluids or fluid releasing agents, and use fibers other than cellulose acetate to provide non-adhesion properties.
Adhesive dressings and methods of preparing adhesive dressings are well known in the art as exemplified by U.S. Pat. No. 4,595,001, and patent references cited therein, to Potter (a surgical dressing which carries an adhesive layer for securing a dressing to a body), all of whose teachings are incorporated herein by reference.
While the above dressings represent improvements in reducing dressing adhesion to wounds, further improvements in the field is highly desirous. In particular, an improved dressing of cellulose acetate would useful in the medical arts because cellulose acetate is both chemotactic for attracting white blood cells and hydrophilic. The white cell chemotactic property of cellulose acetate fibers is desirable in a wound dressing because white blood cells aid in fighting infection. The hydrophilic property is desirable because it aids in removing excess fluids which may ooze from the surface of a wound during the healing process. Accordingly, the present invention is directed to providing such improved dressing.
It is an object of the invention to provide a wound dressing made of cellulose acetate which has improved non-adhesion characteristics.
It is a further object of the invention to provide a wound dressing made of cellulose acetate and a low level of a siloxane finishing agent, which dressing has improved non-adhesion characteristics.
It is an object of the invention to provide a self-adhesive bandage having a wound dressing pad attached thereto, which pad is made of cellulose acetate with or without a low level of a siloxane finishing agent, and which pad has improved non-adhesion characteristics.
It is an additional object of the invention to provide a biostat containing wound dressing and/or self-adhesive bandage having a wound dressing attached thereto, which dressing is comprised in part or wholly of cellulose acetate, and has a low level of a siloxane finishing agent applied thereto; and which dressing has improved non-adhesion characteristics.
SUMMARY OF THE INVENTION
The invention is directed to a wound dressing which does not adhere to a wound surface or which has improved non-adhesion characteristics relative to the wound dressings known to the art. In the one embodiment, the invention comprises a woven or non-woven cellulose acetate dressing. In a preferred embodiment, the invention comprises a non-woven cellulose acetate web, and a particularly preferred nonwoven dressing comprises a spunlace material having a weight of about 20 to about 90 g/m
2
(grams per square meter). These embodiments can further comprise such additional substances as low levels of siloxane materials to finish the dressing or the fibers used to make the dressing and additionally impart further adhesion-reduction characteristics; and anti-bilogics such as bactericides and fungicides which can be incorporated into the cellulose acetate before if is formed into a filament for use in producing the dressing or such anti-biologics incorporated into a fiber which can be used in conjunction with cellulose acetate fibers to produce the dressing.
In another embodiment, the invention is directed to an article of manufacture comprising an adhesive strip having an adhesive on one side thereof and a wound dressing adhering to a portion of the adhesive side of said strip, wherein said wound dressing comprises one or a plurality of layers of a fabric comprising cellulose acetate fibers, biostat-containing cellulose acetate fibers having a biostat content of about 1% to about 5%, and a siloxane in the amount of about 0.01% to about 0.0001%; wherein the amount of biostat-containing fibers in the dressing is from about 1% to about 100% of the total fiber in the dressing.
DETAILED DESCRIPTION OF THE INVENTION
The term “anti-biologic” or “biostat”, and variations thereof, as used herein means any substance which has an effect on a biological organism, and in particular means bactericides, antibiotics, fungicides, herbicides, antimicrobials and similar substances which effect biological organisms, both animal and plant.
The term “dressing” as used herein means any material applied to protect, cushion, cover, and generally guard a wound from either further injury or from any de
Chen John C.
Soden Kevin J.
Greer Burns & Crain Ltd.
Lewis Kim M.
The Regents of the University of California
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