the following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention . various modifications , however , will remain readily apparent to those skilled in the art , since the general principles of the present invention have been defined herein specifically to provide an oxygen releasing bandage based on polyvinyl acetal sponge . the present invention is based on the observation that hydrogen peroxide forms stable complexes with organic polymers that are already used for bandages and wound treatment . many surgical and other wound dressings and sponges are formed from polyvinyl acetal ( also known as polyvinyl alcohol / acetal ) (“ pvaa ”) foam . this material is highly absorbent and does not shed lint or other materials into a wound . as mentioned above it is known that iodine will complex with this polymer to form a useful disinfecting dressing . the present inventor has used pvaa to bind certain organic dyes to create a different disinfectant bandage or dressing material . however , prior to the current invention it was not appreciated that hydrogen peroxide is capable of forming a stable complex with pvaa . the inventor discovered this property by soaking small pvaa sponges ( originally designed for surgical dressings ) in either dilute ( about 3 % wt ./ vol ./) or concentrated ( 35 % wt / vol .) forms . after the sponge is allowed to dry thoroughly , the presence of active hydrogen peroxide can be demonstrated . one means of demonstrating the presence of active hydrogen peroxide is treat the sponge with a few drops of 1 -% sodium iodide ( wt / vol .). sodium iodide is an essentially colorless solution . when iodide is contacted by hydrogen peroxide , the iodide is oxidized to iodine , which appears as a brownish color on the pvaa sponge . as increasing amounts of iodine are generated , the iodine forms a blue - black complex with the pvaa ( not unlike the well - known blue starch - iodine interaction ). therefore , the presence of hydrogen peroxide is easily determined by the formation of a blue - black color upon application of an iodide containing solution . the hydrogen peroxide - pvaa complex is prepared by soaking a suitable pvaa sponge in a hydrogen peroxide solution . generally soaking lasted at least about one hour , but the inventor has not determined the optimal soaking time . the hydrogen peroxide used is in an aqueous or alcoholic solution . since the prior art discloses polyvinylpyrrolidone - hydrogen peroxide complexes formed using hydrogen peroxide in organic solvents , it seems likely that any solvent that does not damage the pvaa could be used . it appears that the interaction between pvaa and hydrogen peroxide is effective with low ( e . g ., 3 %) as well as higher concentrations of hydrogen peroxide ( e . g ., 35 %). however , more concentrated hydrogen peroxide solutions appear to result in formation of a larger weight of the hydrogen peroxide complex . similarly , the complex formation occurs at room temperature as well as at elevated temperature . elevated temperatures are generally those between room temperature and 100 ° c . after soaking , the excess hydrogen peroxide solution is expressed from the pvaa sponge and the resulting sponge is allowed to dry either at room or elevated temperature . the hydrogen peroxide complex formed is stable ( as determined by the iodide test ) essentially indefinitely . by taking the sponge to dryness in an oven ( 120 - 140 ° c .) it is possible to determine that the treated pvaa sponge has gained weight ( as compared to a control sponge treated with water instead of hydrogen peroxide ). the sponge can gain more than 25 % by weight hydrogen peroxide although 5 - 10 % weight increases are more usual and are adequate for practice of the present invention . the hydrogen peroxide complex is also stable if the sponges are not fully dried — that is , allowed to remain slightly moist . this may be an advantage for wound dressing purposes because such materials may remain softer and more flexible . when pvaa - hydrogen peroxide is used as part of a wound dressing , there is a visible amount of foaming if the material comes into contact with the open wound . this is apparently due to the rapid release of oxygen caused by the enzymatic ( primarily catalase and hemoglobin released from the wound ) induced breakdown of hydrogen peroxide into oxygen . as contact with the wound continues obvious foaming decreases as the surface hydrogen peroxide complex becomes depleted . however , as the wound fluids diffuse more deeply into the material oxygen release continues for at least several hours ( based on a pvaa thickness of 0 . 5 cm ). simply taping a pvaa - hydrogen peroxide pad over a wound results in excellent healing . it is believed that the healing improvement is due to the immediate germicidal effect of the hydrogen peroxide and released oxygen . it is not clear that such a loosely taped pvaa - hydrogen peroxide pad achieves a significantly elevated concentration of oxygen around and in the wound . therefore , while pvaa - hydrogen peroxide can be simply taped ( or otherwise held ) on a wound or be used as a pad component in a traditional adhesive bandage , a preferred configuration of a pvaa - hydrogen peroxide wound dressing is shown in fig1 . in the dressing 10 of fig1 a pvaa - hydrogen peroxide pad 12 is attached to the wound - facing surface of plastic member 14 having an adhesive coating 16 . while the configuration appears similar to a traditional bandage , the plastic member 14 is specifically selected to have very low permeability to oxygen . there are a large number of low permeability plastic films known to those of skill in the art including , for example , polybutylene terephahalate , various metallized polymeric film , laminates of metal foil and plastic film , and compound films such as those composed of layers of ethylene - vinyl - acetate and ethylene - vinyl - alcohol . the addition of a plastic member 14 causes oxygen released by the hydrogen peroxide - pvaa complex in the pad 12 to become trapped and concentrated within the dressing and the wound . small pinholes 18 can be made in the membrane 14 so that if oxygen evolution is particularly vigorous , the excess oxygen readily escapes to the atmosphere . otherwise , oxygen pressure can cause partial lifting or release of the bandage 10 . it is believed that an atmosphere of pure oxygen at or only slightly above atmospheric pressure is optimal . it is also possible to include elastic membranes closing the holes 18 or other simple valves to more specifically regulate the actual pressure . when the inventive bandage 10 is applied to a wound 22 , fluids from the wound are drawn into the pad 12 and enzymatic material in the wound fluids catalyze breakdown of the hydrogen peroxide and release of oxygen . apart from oxygen release , the hydrogen peroxide complex is itself inherently antibacterial so that bacteria are not able to live within the bandage 10 . this dual affect of preventing bacterial growth within the bandage 10 and providing enhanced oxygen levels within the wound prevent infection and speed wound healing . in cases where the wound does not produce sufficient enzyme containing fluids to result in adequate oxygen production , it is possible to add liquid to the bandage 10 of the present invention prior to applying it to a wound . the added liquid should contain a small amount of a catalyst of hydrogen peroxide breakdown . such catalysts are well known in the art and include enzymes such as hemoglobin and catalase as well as salts of transition metals such as ferric chloride . while it is possible to simply drop the catalytic solution onto the surface of the bandage , it may be advantageous to prevent contact of the solution with the wound . in such a case , the layered bandage of fig2 may advantageously employed . the layered bandage 20 is similar in structure to the bandage 10 of fig1 ; however , the pvaa pad is split into two layers 12 and 12 ′. an oxygen permeable but water impermeable membrane 24 separates the two layers . such an oxygen permeable membrane 24 can readily be formed from expanded polytetrafluoroethylene film although films of other fluorocarbons as well as other materials are also useable . the catalytic solution is introduced into the upper layer 12 ( this can be done either immediately before attaching the bandage 20 to the wound or immediately thereafter . the solution can be injected into the bandage using a needle that penetrates the plastic member 14 . alternatively , an opening 26 can be provided in the plastic member 14 , which opening is then closed by an additional layer of plastic membrane 28 after introduction of the catalytic solution . the catalytic solution causes breakdown of hydrogen peroxide and concomitant release of oxygen . the oxygen is trapped by the plastic membrane 14 and diffuses through the oxygen permeable membrane 24 and into the wound . at the same time , the oxygen permeable membrane 24 prevents the wound from coming into contact with the catalytic solution . the following claims are thus to be understood to include what is specifically illustrated and described above , what is conceptually equivalent , what can be obviously substituted and also what essentially incorporates the essential idea of the invention . those skilled in the art will appreciate that various adaptations and modifications of the just - described preferred embodiment can be configured without departing from the scope of the invention . the illustrated embodiment has been set forth only for the purposes of example and that should not be taken as limiting the invention . therefore , it is to be understood that , within the scope of the appended claims , the invention may be practiced other than as specifically described herein . fig1 shows a diagrammatic cross - section of a dressing or bandage of present invention . fig2 shows a diagrammatic cross - section of a layered embodiment of invention . 10 whole dressing 12 pvaa pad 14 plastic member 16 adhesive 18 pin holes 20 layered 22 wound 24 oxygen permeable 26 opening 28 sealing layer
an oxygen releasing bandage or dressing is based on a stable complex between polyvinyl acetal and hydrogen peroxide . medical grade polyvinyl acetal sponge is treated with hydrogen peroxide , thereby forming a complex between the acetal plastic and the hydrogen peroxide . the dressing material is then affixed to a wound preferably with an oxygen impermeable covering . fluids from the wound are drawn into the sponge where catalase and other enzymes in the fluids breakdown the hydrogen peroxide to release oxygen . if treatment of relatively dry wounds is desired , catalyst solutions can be introduced into the bandage to stimulate production of oxygen . the bandages are stable for a prolonged period of time .