Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Web – sheet or filament bases; compositions of bandages; or...
Reexamination Certificate
2000-11-09
2002-10-01
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Web, sheet or filament bases; compositions of bandages; or...
C424S400000, C424S401000, C424S422000, C424S423000, C424S434000, C424S435000, C424S445000, C424S484000, C424S489000, C424S049000, C424S077000
Reexamination Certificate
active
06458380
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to dressings and in particular, to dressings for wounds in the oral cavity and for delivering preparations, such as antibiotics, pain medication, or agents for whitening the teeth to selected parts of the body.
Conventional dressings for the oral cavity has not been fully satisfactory. The oral cavity has a high level of bacteria and thus, wounds, including ulcers cannot be adequately treated. Frequently, the wounds take several days to heal and if patients are to be sent home after the surgery, they need to eat during the healing time. This presents additional problems in constructing an appropriate dressing. Various methods of protecting the wound often result in slowed healing around what is commonly a plaster-like material used to cover the wound. This plaster-like dressing can become detached and there is then renewed possibility for infection and bleeding.
It is often necessary to deliver an antibiotic or other pharmaceutical, drug or preparation to a wound or to apply whitening agents to the teeth. However, when such preparations are applied within the oral cavity, it can be difficult to maintain the preparation in its proper location in view of the natural processes which occur within the mouth.
Accordingly, it is desirable to provide an improved wound dressing and system for applying drugs and other treatment preparations to wounds, which overcome the disadvantages of the prior art.
SUMMARY OF THE INVENTION
Generally speaking, in accordance with the invention, a dressing material and method of treating wounds and applying therapeutic materials and preparations to selected parts of the body is provided. The dressing can comprise a water-soluble polymer which is capable of forming a viscous aqueous or non-aqueous solution and form a gel. The gel can be dehydrated to form a foam or powder which can be reconstituted prior to use, or applied directly to a wound. The dressing can be constructed in the form of a sponge or sheet impregnated with the gel, or coated onto a non-porous, porous or micro-porous substrate. The dressing can also be provided in a form of a dehydrated powder, such as one which can be sprinkled under a flap of tissue and which will hold the flap down as a substitute for the use of stitches. Wounds treated with dressings in accordance with embodiments of the invention will tend to heal faster because there is less trauma to the wound or surgical site and because dressings in accordance with the invention do not interfere with healing the body, which can heal at a rapid rate.
Gels in accordance with the invention can comprise acrylic acid polymers, particularly acrylic acid polymers cross-linked with divinyl glycols, and in particular, pharmaceutical resin sold under the name NOVEON, by B.F. Goodrich, Chemical Co. and most preferably the acid form of polycarbophil, meeting the USP monograph for polycarbophil. The general structure of such a resin is the following: —[—CH
2
—HCCOOH—]
n
,— and is drawn below.
The gel can also be formed with preservatives, such as sorbic acid, hydroxides, such as sodium hydroxide and water. In use, the gel, gel in a carrier or gel, carrier and backing can adhere to gum surfaces and is easily removed by direct removal or washing.
Accordingly, it is an object of the invention to provide an improved wound dressing.
It is another object of the invention to provide an improved method of treating wounds.
Still another object of the invention is to provide an improved method and composition for treating wounds in the oral cavity.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention provides a biodegradable matrix in the form of gel formulations and methods for producing the same, which also have the ability to contain, carry and apply chemical elements, such as antibiotics, anti-bacterial agents, bacterial-static agents and other drugs, for preventing or treating infection and to promote, enhance and speed the healing of wounds. The invention also comprises a carrier for the gel formulation, such as a gauze, sponge or other sheet that can become impregnated with the gel formulation and further processing by steps of severe dehydration, such as that associated with lyophilized processing to provide the gel formulation in powder form. The gel and/or gel/carrier composite can also be provided on a support.
The formulations and articles described herein are particularly useful for topical applications within the oral cavity. The formulations comprise water soluble, pharmaceutically and/or oral cavity compatible polymeric material for providing viscosity within acceptable ranges, as determined by the particular application of the gel. The gel formulation provides advantageous controlled release and increased contact time with the intended oral cavity site. Preparing and using therapeutic gels is discussed in U.S. Pat. Nos. 5,876,744 and 5,989,535, which themselves cite earlier patents on this issue and the contents of these patents are incorporated herein by reference.
Gel/carrier and gel/carrier/backing formulations of the present invention have the advantage of adhering to a gum or tooth surface and conforming to the irregular surface contours and membranes encountered within the oral cavity. The gel and composites comprising the gel with the carrier and/or backing may be applied directly to the gum or tooth surface or in conjunction with or without a compliant non-porous, porous or micro-porous substrate, for example, in the form of a coating, to be applied to the oral cavity site intended for specified activity. Composites in accordance with preferred embodiments of the invention have the further advantage of easy application to the oral cavity surface and easy removal by direct removal or washing. Embodiment of the invention can also exhibit the ability to permit increased activity to the intended site and further activity increase through moisture activation of components, if required.
Aqueous gels in accordance with preferred embodiments of the invention will have different viscosities depending on the intended application. The viscosity of gel material prior to the freeze dried processing can have significant effects for a number of reasons. A thinner low viscosity gel in the range of about 1,000 cps up to approximately 10,000 cps, will generally have a lower concentration of solids. The lower concentration of solids in solution can result in a thinner freeze dried product when compared to the same processing steps, lyophilization, applied to a thicker gel, with high viscosity in the range about 10,000 cps to 100,000+ cps, which generally have a higher concentration of solids in solution. Thus, adjusting the viscosity lends itself to the custom or tailored fabrication of the solid foam, porous sheet, resulting product. This would allow thicker materials to be utilized in extended time release of drug or preparation delivery products.
This would also allow thicker materials to fill larger void zones of the oral cavity intended for coverage. This would also lend the thicker product to potentially be less flexible and compliant to contours within the oral cavity where the wound dressing may be required. The thickness may benefit the product efficiency in the prevention of detritus permeation through the dressing to the covered site.
It should also be noted, that this product, regardless of initial thickness, after primary processing (freeze drying), may be pressed via a secondary process step after the completion of the freeze drying procedure. This additional step would allow the physical characteristics, and potential flexibility benefits of a thinner product to be experienced by a “thicker” freeze dried product, resulting in what may be considered a concentrated product formulation or processing step.
The solubility of the material may be adjusted through the addition of non-interacting secondary raw materials to the liquid state formulation mix, or sprayed over the completed product to form a bi-layer, tri-layer, or other multiple layer material that c
Evans Charesse
Frommer Lawrence & Haug
Page Thurman K.
Santucci Ronald R.
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