Drug – bio-affecting and body treating compositions – Effervescent or pressurized fluid containing – Organic pressurized fluid
Reexamination Certificate
2002-01-18
2003-11-18
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Effervescent or pressurized fluid containing
Organic pressurized fluid
C424S400000, C424S405000, C424S434000, C424S422000, C424S484000, C424S489000
Reexamination Certificate
active
06649145
ABSTRACT:
1.0 BACKGROUND ART
1.1 Field of the Invention
The present invention is directed to oxygenating compositions and methods for administering high levels of oxygen to subcutaneous and subepithelial tissues. In particular, methods for surface delivery of super oxygenating compositions for such treatment are described.
1.2 Description of Related Art
In many medical conditions including diabetes, burns, bedsores, and wounds the ability to oxygenate tissue is compromised and arterial oxygen may not reach damaged skin. Tens of thousands of patients die each year in the U.S. as a result of complications from insufficient delivery of oxygen to compromised tissue. Poor oxygen delivery, particularly in the limbs, results in slow healing, infections, scar development, and in the worst cases, tissue death and amputation.
The effect of oxygen tension on wound healing has been extensively studied. (For a review, see Whitney, J. D. (1989)). Wound healing is dependent upon several processes including proliferation of fibroblasts, collagen synthesis, angiogenesis and re-epithelialization. Animal studies have shown that several of these processes are affected by the subcutaneous partial pressure of oxygen (pO
2
). For example, supplemental oxygen can lead to increased rate of collagen deposition, epithelialization and improved healing of split thickness grafts. Increased subcutaneous pO
2
has also been shown to improve bacterial defenses.
Many skin sores, ulcers, wounds and burns do not heal properly because there is a severe depletion of oxygen reaching these affected areas due to deterioration of the associated blood microcirculation. Conventionally, many of these skin diseases have been treated by various methods of administration of oxygen gas, either through inhalation of the gas, or by topical treatment with the gas.
The oldest method of administering oxygen gas to a patient is by hyperbaric chamber technology. This is a systemic treatment, involving placement of a patient in a closed pressurized chamber. Inside the chamber, the patient breathes elevated levels of oxygen gas. The extra oxygen taken in by inhalation becomes dissolved in the bloodstream and diffuses into the body tissues, thereby raising the local tissue oxygen levels. Unfortunately, hyperbaric treatment has not been successful in all situations, in particular where trauma or disease restrict blood flow to the affected tissue. Treatment of skin diseases by placing a patient in a hyperbaric chamber is costly and time-consuming and many patients react unfavorably when placed in hyperbaric chambers. Treatment of many conditions, such as bedsores, for much longer than four hours at one time may induce oxygen toxemia and hence be counterproductive. Toxic effects of hyperbaric treatment include twitching, ringing in the ears, dizziness, and in some cases severe effects such as coma and convulsions. Additionally, hyperbaric treatment is expensive and only available in treatment facilities that are properly equipped with hyperbaric chambers. Patients are only given oxygen through the lungs. The atmosphere of a multichamber hyperbaric unit is ordinary atmospheric gas as there is little known therapeutic value assigned to topical application of oxygen.
To overcome drawbacks associated with systemic hyperbaric treatment, attempts have been made to use “topical hyperbaric” oxygenation devices designed for regional use on an isolated body part such as a limb. In such devices, the delivery route for the pressurized oxygen is topical, as opposed to systemic. Only the affected body part is exposed to the pressurized oxygen. Thus the oxygen gas must diffuse from the surface of the skin to the underlying tissues. For example, U.S. Pat. No. 4,801,291 discloses a portable topical hyperbaric apparatus having a gas impermeable internal chamber into which therapeutic gases are introduced to treat a portion of the patient's body. Similarly, U.S. Pat. No. 5,020,579 discloses a hyperbaric oxygenation apparatus in which a limb is isolated in a portable chamber in the form of an inflatable bag into which oxygen gas is administered through an oxygen port in communication with a patient respirator connected to an oxygen source. The pressure of the oxygen in the collapsible bag is pulsated between maximum and minimum positive values. The patient cyclically experiences first an increase in the blood gas levels on the limb under treatment with a corresponding restriction in blood flow and, thereafter, a progressive return to normal blood flow rates in the limb as the pressure in the chamber changes from maximum to minimum positive pressure.
Several disadvantages exist with the approach of using “topical hyperbaric” oxygenation devices. For example, an external oxygen source and a respirator normally used for respiratory therapy must be supplied with the apparatus. In addition, intermittent restriction and release of blood flow to the treatment area may not be advisable or tolerable for already compromised tissues.
Alternative topical methods to “topical hyperbaric” treatments for poorly healing skin lesions involve the topical application of high levels of oxygen gas through wound dressings. U.S. Pat. No. 5,792,090, discloses an oxygen generating wound dressing and a method of increasing oxygen tension in surface wounds through the application of such a bandage. In this method, the wound dressing contains an oxygen permeable membrane and a reservoir capable of supplying oxygen through a chemical reaction. U.S. Pat. No. 5,855,570 describes another type of oxygen-producing bandage to promote healing of skin wounds. This device combines a wound dressing with an electrochemical, chemical, or thermal means of generating high purity oxygen, and can be regulated to supply oxygen gas to an area above the wound at various concentrations, pressures and dosages.
Unfortunately, topical treatments with oxygen gas such as by topical hyperbaric oxygenation and use of oxygen bandages have provided only minor improvements in promoting healing of skin disorders and in treating diseases. Moreover, peroxide application can generate singlet oxygen O
2
and is a potential source of free radical damage to the skin (Elden, 1995).
1.3 DEFICIENCIES IN THE PRIOR ART
Administration of elevated levels of systemic oxygen gas has been recognized as beneficial in the treatment of several skin disorders; however, the available delivery methods, such as hyperbaric chamber therapy, topical application of oxygen gas, topical hyperbaric treatment of isolated limbs and use of oxygen-producing bandages are at best minimally effective and often lead to problems that include toxicity and poor oxygen penetration of the skin. Currently used procedures for treatment of skin disorders such as ulcers, bedsores, and burns may exacerbate the existing skin disorder.
It is therefore desirable to provide methods of treatment for skin disorders that increase tissue oxygenation to induce more rapid healing of the skin, while not exacerbating an existing condition or causing additional side effects.
2.0 SUMMARY OF THE INVENTION
Conventional methods of increasing tissue oxygenation employ oxygen gas. In distinct contrast, the present invention discloses a novel method of increasing tissue oxygenation by topical application of a superoxygenated composition. The superoxygenated compositions rapidly raise oxygen partial pressure levels in the tissue by promoting efficient diffusion of oxygen into the tissue.
Accordingly, the invention discloses a method of increasing tissue oxygenation in mammals, comprising applying a superoxygenated composition to a tissue surface for a time sufficient to increase the subepithelial partial oxygen pressure from about 30% to about 120% above baseline pO
2
. The mammal will generally be a human, but there is no limitation to its use in veterinary applications to small and large animals that may have tissue damage responsive to therapeutic procedures that increase oxygenation of tissues.
The most common applications are direct application to the external skin but the method is
Fox Charles
McGrath Terrence S.
Berko Retford
Hydron Technologies, Inc.
Kim Stanley A.
Senterfitt Akerman
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