Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Web – sheet or filament bases; compositions of bandages; or...
Reexamination Certificate
2001-07-27
2003-02-18
Webman, Edward J. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Web, sheet or filament bases; compositions of bandages; or...
C514S772400, C514S772600, C424SDIG001
Reexamination Certificate
active
06521251
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention is directed to methods for treating burns on mammalian skin to reduce the risk of infection and to minimize fluid loss. Specifically, the methods of this invention involve the in situ formation of a polymeric cyanoacrylate film over the mammalian skin surface at the site of the burn. The cyanoacrylate film acts as a barrier inhibiting the introduction of pathogens (e.g., bacteria) into the burn area and as a barrier for the loss of fluids. Preferably, the cyanoacrylate prepolymer comprises an antimicrobial agent which is incorporated into the polymeric film to further retard the introduction of pathogens into the burn area.
References
The following publications, patent applications and patents are cited in this application as superscript numbers:
1
Barley, “Methods for Retarding Blister Formation by Use of Cyanoacrylate Adhesives”, U.S. Pat. No. 5,306,490, issued Apr. 26, 1994.
2
Barley, et al., Methods for Treating Suturable Wounds by Use of Sutures and Cyanoacrylate Adhesives, U.S. Pat. No. 5,254,132, issued Oct. 19, 1993
3
McIntire, et al., Process for the Preparation of Poly(&agr;-Cyanoacrylates), U.S. Pat. No. 3,654,239, issued Apr. 4, 1972
4
Barley, et al., International Patent Application Publication No. WO 93/25196, for Methods for Treating Non-Suturable Wounds by Use of Cyanoacrylate Adhesives, published Dec. 23, 1993
5
Barley, et al., Methods for Reducing Skin Irritation From Artificial Devices by Use of Cyanoacrylate Adhesives, U.S. Pat. No. 5,653,789, issued Aug. 5, 1997
6
Tighe, et al., Methods for Inhibiting Skin Ulceration by Use of Cyanoacrylate Adhesives, U.S. Pat. No. 5,403,591, issued Apr. 4, 1995
7
Tighe, et al., for Use of Cyanoacrylates for Providing a Protective Barrier, U.S. Pat. No. 5,580,565, issued Dec. 6, 1996
8
Askill, et al., for Methods for Draping Surgical Incision Sites, U.S. Pat. No. 5,807,563 issued Sep. 15, 1998
All of the above publications, patent applications and patents are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent application or patent was specifically and individually indicated to be incorporated by reference in its entirety.
State of the Art
Reduced morbidity and/or infection associated with burns on mammalian skin relate directly to the severity of the burn and the level of care provided. Mammalian skin burns are classified into three categories:
first degree burns which are superficial burns characterized by redness and blanching (turns white upon exposure to pressure). First degree burns damage only the top or epidermal layer of the skin and can be associated with low to moderate pain, although severe pain can also arise, and a relatively low risk of infection;
second degree burns which are partial thickness burns. These burns involve the entire epidermis and some portion of the dermis and are associated with moderate to severe pain, a higher risk of infection and loss of body fluid through the exposed dermis; and
third degree burns which are full thickness burns involving the entire epidermal and dermal layers. Such burns involve the entire epidermis and the dermis of the burned skin and are associated with severe pain, a very high risk of infection and loss of significant amounts of body fluid.
As is apparent, the risk of infection and morbidity arising from burns increases with the severity of burn and, accordingly, treatment protocols for burns emphasis the need to quickly inhibit the introduction of microbes into the burn site from either endogenous sources or from air borne microbes. In addition, the burn site should be covered with appropriate bandages, etc. to reduce fluid loss and to protect the burn site from further trauma arising from, for example, accidental contact therewith.
However, often bandages and other wound dressings do not inhibit bacterial migration into the burn site because these dressings to not adequately isolate the burn site.
This invention is directed, in part, to the discovery that the in situ formation of a cyanoacrylate polymeric film at the burn site overcomes many of the prior art problems associated with the use of conventional burn dressings. For example, the cyanoacrylate polymer is known in the art to have bacteriostatic properties and the cyanoacrylate monomer permits the inclusion of compatible antimicrobial agents if such is desired. Still another advantage is the formation of an appropriately configured film which completely covers the burn area and forms a water proof film over the skin, thereby inhibiting fluid loss.
The use of cyanoacrylate polymers per this invention is in contrast to their known medical uses as an alternative or adjunct to sutures
2
or as a hemostat
3
. Other described uses of cyanoacrylate prepolymers include their use on mammalian to form polymeric films which are utilized:
to prevent friction blister formation
1
,
in treating small non-suturable wounds
4
,
in inhibiting surface skin irritation arising from friction between the skin surface and artificial devices such as tapes, prosthetic devices, casts, etc.
5
,
as surgical incise drapes
8
,
in inhibiting skin ulcerations
6
, and
forming a protective film to inhibit skin degradation due to incontinence.
7
SUMMARY OF THE INVENTION
This invention is directed to methods for treating the burn site on mammalian skin in order to reduce the risk of infection and to form a waterproof film which inhibits fluid loss from this site.
Such methods involve application of a cyanoacrylate prepolymer composition onto the burn site followed by in situ polymerization of the prepolymer to form a polymeric film. The cyanoacrylate prepolymer composition can be applied as a liquid/gel to the skin surface and can include therapeutic agents such as analgesics, anti-inflammatory agents, antimicrobial agents, etc.
In all but third degree burns, the polymeric film will naturally shed from the skin surface 1-4 days after application and, accordingly, there is no need to effect removal of the film or to cause the skin trauma potentially associated with film removal. This polymeric film forms a bacteriostatic or bactericidal barrier to external sources of burn contamination as well as barrier to fluid loss through the burn site. Moreover, in a preferred embodiment, the cyanoacrylate composition is formulated to contain an antimicrobial agent which, over time, will be released from the resulting film thereby providing for protection against infection at the burn site.
Accordingly, in one of its method aspects, this invention is directed to a method for forming an adherent, surface conforming film at a burn site on the mammalian skin surface of a patient which method comprises:
(a) identifying the extent of the burn site on the mammalian skin surface of the patient;
(b) applying a sufficient amount of a composition comprising a polymerizable cyanoacrylate ester to the burn site defined in (a) above so as to cover this site with the composition; and
(c) polymerizing the cyanoacrylate ester so as to form a flexible, waterproof, adhesive polymer layer which adheres to the area(s) where the composition was applied.
Preferably, the polymerizable cyanoacrylate ester comprises an ester which, in monomeric form, is represented by formula I:
where
R is selected from the group consisting of:
alkyl of 1 to 10 carbon atoms,
alkenyl of 2 to 10 carbon atoms,
cycloalkyl groups of from 5 to 8 carbon atoms,
phenyl,
2-ethoxyethyl,
3-methoxybutyl,
and a substituent of the formula:
wherein each R′ is independently selected from the group consisting of:
hydrogen and methyl, and
R″ is selected from the group consisting of:
alkyl of from 1 to 6 carbon atoms,
alkenyl of from 2 to 6 carbon atoms,
alkynyl of from 2 to 6 carbon atoms,
cycloalkyl of from 3 to 8 carbon atoms,
aralkyl selected from the group consisting of benzyl, methylbenzyl and phenylethyl,
phenyl, and
phenyl substituted with 1 to 3 substituents selected from the group consisting of hydroxy, chloro, bromo, nitro, alkyl of 1 to 4 carbon atoms, and al
Askill Ian N.
Karnik Shane
Burns Doane Swecker & Mathis L.L.P.
Flowers Park Ltd.
Webman Edward J.
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