AND METHOD OF USE THEREOF

BACKGROUND OF THE INVENTION

The present invention relates to drapes for the protection of living tissues. More particularly, it relates to flexible incise surgical drapes which are useful in the protection of human and animal skin from attack by harmful agents such as microorganisms, and from damage due to physical stresses imposed by detachment of the drape from the skin. The drape is comprised of a structural layer and a specially adapted adhesive hydrogel layer, the hydrogel layer optionally containing dopants such as antibiotics, antivirals, antifungals, salts, colorants and medications.

Surgical drapes are commonly used by medical personnel to create and maintain a sterile field through which the patient may be accessed for a surgical procedure. A surgical

1 preparation typically does not sterilize the skin, it only disinfects it. Bacteria on the skin can survive and be carried into the incision made through the drape during the surgical procedure. Surgical drapes can help reduce the risk of surgical site infections by immobilizing microorganisms on the skin and by providing continuous antimicrobial activity. Surgical drapes may also provide a fluid-resistant barrier. Many drapes feature an absorbent, protective barrier of material throughout the drape that inhibits strikethrough and provides resistance to microbial penetration. Surgical site infections are both damaging to patient recovery and expensive to treat. On average, a surgical site infection adds 9.7 more post operative hospital days and costs $20,842 in extra hospital charges (de Lissovoy G, Fraeman K, Hutchins V, Murphy D, Song D, Vaughn BB. Surgical Site Infection: Incidence and Impact on Hospital Utilization and Treatment Costs. Am J Infect Control 2009; 37:387-97.)

United States Patent 4,601,286 to Kauffman discloses a laser surgical drape having an aperture for the passage of laser energy and incorporating a hydrogel layer.

It is known in the prior art to employ hydrogels as wound dressings, specifically because these dressings exhibit no adhesion to the wound. That is the reason that they are used to cover bums, as the lack of adhesion allows the healing tissue to move freely and reduces scarring. When dressings are changed, the lack of adhesion prevents reinjury to the underlying tissue.

Some patients needing surgery have skin that is more fragile than usual and is prone to damage from applied forces. Such patients may suffer from skin ailments ranging from autoimmune diseases of the skin to damage from infections by vims, bacteria, and fungus, to advanced age that results in frailty of the skin. In such patients, removal of a surgical drape that is affixed to the skin by an adhesive often results in erythema, skin stripping, and adhesive residue damage to the skin requiring follow-up intervention to prevent and treat infection and to promote healing.

It would therefore be advantageous to provide a surgical drape having an adhesive that may be removed without imposing damaging forces on the underlying skin. It would further be advantageous to provide an adhesive for retaining a surgical drape in place on the skin that

2 also maintains the skin in a state of hydration to reduce the likelihood of skin damage upon removal of the drape. It would also be advantageous to have an adhesive that incorporates agents that reduce the population of bacteria, virus, fungus, and other harmful agents on the skin, and reduce the likelihood that such agents will invade the surgical site. Unlike the hydrogel wound dressings of the prior art which intentionally exhibit no adhesion, the hydrogel of the present invention has sufficient adhesion to retain the surgical drape in position during a surgical procedure, and yet exhibits little or no peel force at high peel angles so that removing the drape does not inflict injury on the skin to which it is adhered. BRIEF DESCRIPTION OF THE DRAWING

FIG. l is a section view of a surgical drape according to the present invention.

SUMMARY OF THE INVENTION

The present invention is a surgical drape comprised of a flexible film having disposed on one surface a hydrogel adhesive formulated and processed to provide good adhesion to skin, combined with very low peeling force required for removal of the drape. Optionally, the hydrogel may contain one or more dopants providing antibiotic, antiviral and/or antifungal properties to the hydrogel. In use, the drape is removed from the skin by peeling at a high angle, preferably greater than 160° to reduce the force transmitted to the underlying skin.

3 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with the present invention, it has now been found that skin may be protected from damage due to forces associated with the removal of surgical drapes by using a drape having an adhesive layer comprising a hydrogel formulated and processed to provide good adhesion to skin, combined with very low peeling force.

Thus, in accordance with the present invention there is provided an incise surgical drape comprising:

1. A flexible film having a top surface and a bottom surface;

2. A hydrogel adhesive layer disposed on the bottom surface of the film; a. The hydrogel comprising a mixture of from 10% to 30% polyvinylpyrrolidone (PVP, e.g, K90) and from 5% to 40% Polyethylene glycol (e.g., PEG 300,

PEG 400), by weight, with the remainder being water, and small amounts of an organic acid (to adjust pH to within a range of 4 to 9) and a medically acceptable preservative (e.g., 0.1% benzalkonium chloride solution or parabens.) b. Optionally, the hydrogel may contain one or more dopants (additives) selected to provide desired properties such as antibacterial, antiviral, and antifungal, coloring, or other medication.

In FIG. 1 there is shown in cross section a surgical drape 10. Drape 10 comprises a flexible film 11 having a top surface 11a and a bottom surface 1 lb. Disposed on bottom surface 1 lb is a hydrogel layer 12.

In the preferred embodiment, flexible film 11 is comprised of polyethylene, and may be any appropriate thickness as required for structural stability and flexibility, as well as suitability for incision during a surgical procedure. Alternatively, other polymeric films known in the art may be employed. As a further alternative, other films or fabrics having sufficient dimensional strength may be employed, such as woven or non-woven fabrics comprising natural fibers, synthetic fibers, or a mixture thereof.

4 The preferred method for manufacturing the surgical drape of the present invention is as follows:

A uniform degassed slurry comprising a mixture of from 10% to 30% polyvinylpyrrolidone (PVP, K90) and from 5% to 40% Polyethylene glycol (PEG 300), by weight, with the remainder being water, and small amounts of an organic acid (e.g., citric acid) to adjust pH to within a range of 4 to 9, and a medically acceptable preservative (e.g., 0.1% benzalkonium chloride solution or parabens) is prepared. The slurry is uniformly deposited or extruded onto film 11, and the slurry is then exposed to electron beam radiation to initiate crosslinking of the PVP and PEG, thereby forming hydrogel layer 12. Electron beam energy used may range from 1 megarad to 12 megarads. Varying the ratio of PVP to PEG, the concentration of the mixture in the slurry, and the amount of electron radiation exposure permits hydrogels having varying degrees of adhesion to skin to be produced.

In the preferred embodiment, the peel force required to remove the surgical drape from clean stainless steel is at or near 0 grams using a 180° peel angle, and less than 65 grams using a 90° peel angle. Alternative embodiments may exhibit peel force up to 10 grams using a 180° peel angle. In practice, fragile skin is left undamaged by removal of the surgical drape of the present invention, even after an extended period of adhesion.

An alternative embodiment may substitute PEG 400 for some or all of the PEG 300.

Another embodiment may add a dopant to the slurry to provide antibacterial, antifungal, and/or antiviral activity, selected from the following:

Lipopeptides; Fluoroquinolone; Lipoglycopeptides; Cephalosporin; Macrocyclics; Beta- lactams; Penicillins; Cephalosporins; Oxacephems; Carbacephems; Monobactams; Carbapenems; Macrolides; Lincosamides; Streptogramins; Aminoglycosides; Quinolones; Sulfonamides; Tetracyclines; Chloramphenicol; Metronidazole; Tinidazole; Nitrofurantoin; Glycopeptides; Lipoglycopeptides; Oxazolidinones; Rifamycins; Polypeptides; Tuberactinomycins; Topical antibiotics (including silver compounds, chitosan, antimicrobial peptides); Betadyne; Chlorhexadine; Povidone-iodine; Iodine; Hydrogen Peroxide; Nystatin;

5 Amphotericin b; Micafungin; Anidulafungin; Caspofungin; Terbinafme; Griseofulvin; Flucytosine; Fluconazole; Itraconazole; Clotrimazole; Ketoconazole; Voriconazole; Posaconazole; Isavuconazonium; Itraconazole; Miconazole. EXAMPLES

The following examples illustrate but do not limit the scope of the invention which is defined by the claims. All tests were conducted using a clean stainless steel plate as the adhesion surface. Test samples were 1” wide and tested at 12 ipm using a Chemlnstruments Adhesion tester. In these examples, crosslinking electron beam exposure ranged from 1 Megarad to 18 Megarads. In each test, the 90° peel is indicative of the adhesive quality of the sample, while the 180° peel is indicative of the ability of the sample to protect the skin from damage.

Example 1 (Prior Art): 3M™ Ioban™ 2 Antimicrobial Incise Drape:

90° Peel Test - Avg of 4 tests, 514.4 Grams 180° Peel Test - Avg of 4 tests, 632.75 Grams Example 2: 20% PVP / 15% PEG approx. 6 mils thick 90° Peel Test w/30min dwell time Avg 38.3 Grams 180° Peel Test - Avg 0.0 Grams

Example 3: 20% PVP / 20% PEG approx. 6 mils thick

90° Peel Test w/30min dwell time - Avg 44.1 Grams 180° Peel Test - Avg 0.0 Grams

Example 4: 25% PVP / 15% PEG approx. 6 mils thick

90° Peel Test w/30min dwell time - Avg 50.9 Grams

6 180° Peel Test - Avg 0.0 Grams

Example 5: 20% PVP / 17.5% PEG approx. 6 mils thick

90° Peel Test w/30min dwell time - Avg 54.6 Grams 180° Peel Test - Avg 0.0 Grams Example 6: 25% PVP / 20% PEG approx. 7 mils thick 90° Peel Test w/30min dwell time - Avg 57.0 Grams 180° Peel Test - Avg 3.9 Grams

Example 7: 25% PVP / 25% PEG approx. 7 mils thick

90° Peel Test w/30min dwell time - Avg 63.6 Grams 180° Peel Test - Avg 6.5 Grams

While the invention has been described in its preferred embodiments, it is to be understood that the words which have been used are words of description rather than of limitation and that changes may be made within the purview of the appended claims without departing from the true scope and spirit of the invention in its broader aspects. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention. The inventors further require that the scope accorded their claims be in accordance with the broadest possible construction available under the law as it exists on the date of filing hereof (and of the application from which this application obtains priority, if any) and that no narrowing of the scope of the appended claims be allowed due to subsequent changes in the law, as such a narrowing would constitute an ex post facto adjudication, and a taking without due process or just compensation.

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