The use of squalene, squalane or mixtures thereof for preparing a cooling composition for the local treatment of burns

Abstract: A therapeutic coolant for the local treatment of burn is provided wherein said coolant consisting of squalene, squalane, or mixtures thereof. A method of treating burn is provided wherein said method comprising : applying a therapeutic coolant cooled to a temperature range from -10 to -60°C, said coolant selected from the group consisting essentially of squalene, squalane, or mixtures thereof.

Description: (1) Field of the Invention The present invention relates to the preparation of a therapeutic coolant for the local treatment of burn, specifically in its early stages. (2) Description of the Prior Art It has been well known that cooling by tap water is effective for the treatment of burn in its early stages. Although this is a convenient method, it is necessary to sterilize the water in advance for the purpose of preventing infection. Tap water itself does not have an intrinsic therapeutic effect for burn. Therefore, a further medical treatment such as application of an ointment to the burned skin is necessary for remedy after cooling the region by tap water. One of the principal advantages of water such as tap water as a coolant is that appropriate latent heat accompanying the change in state of water such as vaporization can be utilized in cooling. In other materials wherein such latent heat can not be utilized, it is inevitable to cool them to an extremely low temperature sufficient to make them exhibit their cooling effect. However, it is sometimes difficult to cool to such a low temperature, and there is the fear of causing frostbite. Conventional oily medicines, for example, applied to the skin have not a sufficient cooling effect, because they have a tendency to become a solid when cooled to such an extremely low temperature. Medicines for the local protection of the skin such as glycerine, gel, vaseline and the like, have not such a tendency to be solidified but become too viscous to be applied smoothly to the skin at an extremely low temperature, and they also have not a sufficient cooling effect. For the above reasons, there is a desire for a more efficient and convenient coolant to be used for remedy of burn in its early stages. It has been shown that squalene is a bactericide useful as a drug for the treatment of skin diseases, among others burn (JP-A-53-79036. SUMMARY OF THE INVENTION It is an object of the present invention to provide a convenient, therapeutic coolant for the local treatment of burn. DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the use of squalene, squalane or mixtures thereof for preparing a cooling composition for cooling burnt skin, said composition being cooled to a temperature of -10°C to -60°C and suitable to be applied to the burnt skin in an amount of 0.001 to 1g/cm² in terms of squalene or squalane. In the present invention, squalene, squalane, or mixtures thereof are cooled to an extremely low temperature such as - 10 to -60°C, preferably -20 to -50°C, more preferably -40°C, and the resultant coolant is used as a therapeutic coolant for the treatment of burn its early stages. At a temperature higher than - 10°C, the cooling effect is insufficient. Although squalene, squalane, or mixtures thereof maintain their liquid state at a temperature not more than - 60°C, it is not practical to cool them to such an extremely low temperature, but also not safe because there is the danger of causing frostbite. Squalene, squalane, or mixtures thereof have a melting point sufficiently low to be able to maintain their liquid state and can form a low viscous liquid even at a temperature range from -10 to -60°C. Further, if the coolant comprising squalene, squalane, or mixtures thereof cooled to the above temperature range is sterilized in the course of said cooling, there is almost no fear of infection. In the present invention, squalene or squalane may be natural products or synthetic products, said natural products being squalene or squalane extracted from animal oil or vegetable oil such as shark liver oil or olive oil. Squalane obtained by hydrogenation of the carbon to carbon unsaturated double bonds in squalene may be used. Further, mixtures of squalene and squalane in any weight ratio may be employed in the present invention. Among them, squalane is most preferable, because of its excellent oxidation stability. Squalene, squalane, and mixtures thereof do not cause any sensitization, and may be applied directly to the site of the burned skin immediately after burn to achieve the objective. The cooling composition of squalene, squalane, or mixtures thereof are suitable to be applied in an amount of 0.001 to 1 g./cm² to the burned skin region. According to the present invention, squalene, squalane, or mixtures thereof may be blended with other known therapeutic agents used for the local treatment of the skin and mucosa. Examples of the therapeutic agents include conventional local astringents; conventional local protective medicines, such as white vaselin; antiphlogistics, analgesics; disinfectants such as iod povidone, gluconic acid chlorhexydine; antibacterial drugs such as silver sulfadiazine, gentamicin sulfuric acid; antihistaminics; steroid and non-steroid antiinflammatory drugs such as betamethasone valeric acid; enzyme type antiphlogistics; immunosuppressants; antiinflammatory drugs such as guaiazulene; and the like. Antioxidants such as vitamin E may be also employed to improve the oxidation stability of squalene. Diluents such as hydrocarbons which have no stimulus to skin, may be also blended with the coolant prepared in the present invention. Experiment (Experimental Method) Male Wistar rats (weighing 32.6 to 32.7 pounds) were used in the following experiments. After removing the hair from the back of each rat by means of a depilatory lotion, the bare back skin was applied with hot water to produce deep dermal burn extending over the area having a diameter of 28 mm on either side of the back. The burned skin on the right side is referred to as the treated side, and that on the left side as the control side. Sixty rats were used to form 3 groups of 20 each. The backs of the rats in each group were burned in the manner mentioned above, and treated as follows. A specimen was collected from each wound after 24 hours and 1 week. Pathological specimens were prepared by means of the hematoxylin and eosin stain and inspected under an optical microscope. 1st Group : Right side : Squalene cooled to - 40°C in advance was applied 5 times to the wound in an amount of 0.1 g/a time at 10 seconds intervals. Left side : control (untreated) 2nd Group : Right side : The same procedure as above was performed with squalane (at- 40 °C). Left side : control (untreated) 3rd Group : Right side : The same procedure as 1st Group was performed with distilled water (at 20°C). Left side : control (untreated) (Results) The following observations on the pathological tissue were made after 24 hours and 1 week: An eosinophilic layer which was supposed to be changed to the morbid state by heat was observed in the upper dermis over a relatively wide area in the control Groups. Such destructive changes were mild in the treated groups. The swelling of the collagen fibers and destruction of the adnexa were observed remarkably in the control group. In the deep dermis, bright edematous layers occurred more or less even in the treated group, but they were observed remarkably in the control group. And, the new growth of the capillaries in the dermis was observed in the control group. Table 1 shows the results indicating a relatively minor change of the skin in the treated group. The appraisals in Table 1 were based on the following states: 1 observed all over 2 observed over a major area 3 observed over a major area of about half the number 4 observed partially 5 scarcely observed

Claims: The use of squalene, squalane or mixtures thereof for preparing a cooling composition for cooling burnt skin, said composition being cooled to a temperature of -10°C to -60°C and suitable to be applied to the burnt skin in an amount of 0.001 to 1g/cm² in terms of squalene or squalane. The use according to Claim 1, wherein the composition additionally comprises one or more therapeutic agents and/or the usual pharmacaceutical additives. The use according to Claim 1, wherein the composition is a cosmetic composition for the treatment of sunburn. The use according to Claim 3, wherein the composition additionally comprises cosmetic additives.

Inventors: DOI HIDEAKI, OGAWA YUTAKA, DOI, HIDEAKI, OGAWA, YUTAKA
Applicants: NIPPON PETROCHEMICALS CO LTD, NIPPON PETROCHEMICALS COMPANY, LIMITED
Application year: 1991
Main classification: A61K31
IPC codes: A61K31, A61P17