1. Field of the Invention
This invention relates to a method for treating outer ear infection in dogs and cats, otitis externa, with a di-enzymatic biocidal system in a substantially non-aqueous carrier. The di-enzymatic system, upon application to the outer ear, generates a hypoiodite which is a biocidal agent.
Otitis externa is a classification for infection of the external ear canal that begins at the outside opening of the ear and extends inward to the eardrum. Associated causes of otitis externa include bacteria, fungus, virus, yeast, and ear mites. The ears of dogs, particularly those with pendulous ears, and cats provide an environment for the infectious growth of bacteria, fungus and yeast because they are moist and warm and contain wax and other debris.
2. Related Art
It is disclosed in U.S. Pat. No. 4,331,686 (Djurickovic, 1982) that the most frequent microorganisms found in dogs affected with otitis externa are blastomyces, staphlococci, pytrosporum canis, pseudomonas, proteus and prototheca wickerhammii. This reference also discloses that the treatment of otitis externa has been based on prolonged deep instillation of antibiotics, antifungals, corticosteroids, and proteolytic enzymes.
The use of enzymatic systems to produce an antibacterial or biocidal effect is disclosed in the prior art.
U.S. Pat. No. 4,370,199 (Orndorff, 1983) discloses a method of killing and inhibiting the growth of microorganisms in industrial process streams by the addition of an enzymatically catalyzed biocide system which utilizes a plant dehydrogenase enzyme such as horseradish peroxidase in the presence of an oxidant such as hydrogen peroxide to oxidize a halide salt such as potassium iodide or sodium chloride to produce an oxidation product that is toxic to microorganisms.
U.S. Pat. No. 4,150,113 (Hoogendoorn et al., 1979) and U.S. Pat. No. 4,178,362 (Hoogendorn et al., 1979) disclose, respectively, an enzymatic toothpaste and an enzymatic chewable dentifrice containing glucose oxidase which acts on glucose present in saliva and tooth plaque to produce hydrogen peroxide. The patentees note that oral bacteria, through enzyme systems having SH-Groups, effect glycolysis of food products containing sugars and point out that lactoperoxidase, which is present in saliva, provides the means for transferring oxygen from hydrogen peroxide to oral bacteria resulting in the oxidation of the SH-containing enzymes into inactive disulfide enzymes. It is further disclosed that the dentifrice may be formulated with potassium thiocyanate.
U.S. Pat. No. 4,269, 822 (Pellico et al., 1981) discloses an antiseptic dentifrice containing an oxidizable amino acid substrate and an oxidoreductase enzyme specific to such substrate for producing hydrogen peroxide and ammonia upon oral application of the dentifrice, with pre-application stability being maintained by limiting the quantity of any water present in the dentifrice.
U.S. Pat No. 4,537,764 (Pellico et al., 1985) discloses an enzymatic dentifrice containing Beta-D-glucose and glucose oxidase for producing hydrogen peroxide upon oral application of the dentifrice, with pre-application stability being maintained by limiting any water in the dentifrice to not more than about 10 wt. % based on the weight of the dentifrice.
U.S. Pat. No. 4,576,817 (Montgomery et al., 1986) discloses enzymatic bandages and pads, for body contact applications, containing, for example, glucose oxidase which catalyzes the interaction of Beta-D-glucose, water and oxygen in the serum to produce hydrogen peroxide, and wherein the bandages and pads may further contain a peroxidase and an oxidizable salt such as thiocyanate, chloride or iodide salt of sodium or potassium which, in the presence of hydrogen peroxide and peroxidase are oxidized to thiocyanate (sic), hypochlorite and hypoiodite, respectively, that function as bacterial inhibitors.
U.S. Pat. No. 4,564,519 (Pellico et al., 1986) discloses a di-enzymatic chewable dentifrice which contains, for example, glucose and glucose oxidase for producing hydrogen peroxide upon chewing the dentifrice and further contains a thiocyanate salt and lactoperoxidase for interacting with hydrogen peroxide to produce a hypothiocyanate (sic) bacterial inhibitor, with pre-application stability being maintained by limiting any unbound water in the chewable dentifrice to an amount not more than about 1.0 wt. % and limiting the total water, bound and unbound, to not more than about 10 wt. %.
U.S. Pat. No. 4,578,365 (Pellico et al., 1986) discloses a di-enzymatic dentifrice which contains, for example, glucose and glucose oxidase for producing hydrogen peroxide upon oral application of the dentifrice and further contains a thiocyanate salt and lactoperoxidase for interacting with hydrogen peroxide to produce a hypothiocyanate (sic) with pre-application stability being maintained by limiting any water in the dentifrice to not more than about 10 wt. % based on the weight of the dentifrice.
U.S. Pat. No. 4,617,190 (Montgomery, 1986) discloses enzymatic powder milk which contains, for example, glucose, glucose oxidase, a peroxidase and potassium iodide for producing hypoiodite, an anionic bacterial inhibitor in the reconstituted milk.
U.S. Pat. No. 5,336,494 (Pellico, 1994) discloses an orally chewable, enzymatically coated pet product which contains, for example, Beta-D-glucose and glucose oxidase for producing hydrogen peroxide upon oral chewing of the product and may further contain a peroxidase and an alkali metal salt of an oxygen accepting anion such as potassium iodide for interacting with hydrogen peroxide to produce hypoiodite, an anionic bacterial inhibitor.
U.S. Pat. No. 5,453,284 (Pellico, 1995) discloses an aqueous enzymatic dentifrice having a water content in excess of 10 Wt. % and which contains, for example, Beta-D-glucose and glucose oxidase for producing hydrogen peroxide upon oral application of the dentifrice and may further contain a peroxidase and an oxidizable alkali metal salt such as the thiocyanate, chloride or iodide salt of sodium or potassium for interacting with hydrogen peroxide to produce an anionic bacterial inhibitor, with pre-application stability being maintained by the addition of a water soluble thickener in an amount to provide the dentifrice with a viscosity from about 800 to about 75,000 centipoises.
Each of the foregoing patent references is incorporated herein by reference thereto.
It would be very advantageous to provide a method for treatment of otitis externa with an enzymatic biocidal composition which is particularly adapted for use in the environment of the outer ear.