21~497g TOPICAL PHENYLEPHRINE PREPARATION
FIELD OF THE INVENTION
This invention relates to a topical preparation containing phenylephrine for application to the skin in the vicinity of a wound to substantially reduce bleeding from the wound.
BACKGROUND OF THE INVENTION
Human skin is a multilayer structure containing a complex network of blood vessels. The upper layer of the skin, the epidermis, comprises sheets of cells and provides a protective outer layer over the entire body. Beneath the epidermis is the dermis which contains nutritive arteries, veins and capillaries which supply nutrients to the skin. Located below the dermis is a subcutaneous layer containing the venous plexus, which holds large quantities of blood to heat the surface of the skin.
In order to regulate skin temperature, arteriovenous (AV) anastomoses are provided in the dermis, comprising large vascular communications directly between the arteries in the dermis and the subcutaneous venous plexus. The AV anastomoses have strong muscular walls innervated by sympathetic vasoconstricting nerve fibres and when constricted, reduce or stop the flow of blood between the arteries of the dermis and the venous plexus.
Although this vasoconstricting effect is most powerful in parts of the body containing AV anastomoses, such as the hands, feet, lips, nose and ears, the skin throughout the body contains sympathetic vasoconstrictor nerve fibres which provide vasoconstrictive control of the nutritive vessels in the dermis.
These sympathetic vasoconstrictor nerve fibres are provided with adrenergic receptors, the two main types of which are classified as alpha receptors and beta receptors.
Stimulation of alpha receptors causes vasoconstriction of blood 21~ 1973 vessels, whereas beta receptor stimulation causes dilation of blood vessels. Drugs which can stimulate either alpha or beta receptors can be used to increase or decrease blood circulation in the dermis.
Phenylephrine is a known sympathomimetic agent and is believed to stimulate alpha receptors of sympathetic vasoconstrictor nerve fibres and thereby cause vasoconstriction. Phenylephrine is commonly found in over-the-counter preparations for temporary relief of nasal congestion.
Its decongesting effect is produced by constriction of the smaller arterioles of the nasal passages. Phenylephrine and other sympathomimetics have also been used in epistaxis (nosebleed) control, and in dentistry and surgery to minimize blood loss during surgical procedures.
Phenylephrine is also known to produce vasoconstriction in the AV anastomoses and nutritive vessels of the skin.
However, the disadvantage exists that, to date, phenylephrine has not been used in a topically applied form as a treatment to stop or reduce bleeding from skin wounds, particularly cutaneous bleeding from minor skin wounds.
SUMMARY OF THE INVENTION
To overcome the above disadvantage, the inventors have found that topical application of phenylephrine or one of its physiologically active salts, in the vicinity of a bleeding skin wound, can substantially reduce or eliminate the flow of blood from the wound.
Accordingly, the inventors have developed a topical preparation containing phenylephrine as a treatment to substantially reduce or stop bleeding from skin wounds.
Preferably, phenylephrine is present in the topical preparation as phenylephrine hydrochloride. Preferably the concentration of phenylephrine in the topical preparation is from about 0.5%
to about 50% by weight.
Preferably, the topical preparation of the present ~lS497~
invention is in the form of an ointment, cream, or liquid, comprising an effective amount of phenylephrine and a base, the type of base depending on the site of application and reason for use. For example, bases for an ointment or cream maybe selected from organogels, hydrogels, and emulsion-type semisolids.
It is one object of the present invention to provide a topical preparation containing phenylephrine in an amount effective to constrict blood vessels in and below the skin.
It is another object of the present invention to provide a topical preparation containing phenylephrine in an amount effective to substantially reduce or stop cutaneous bleeding from a skin wound.
In one aspect, the present invention provides a topical preparation comprising: phenylephrine; and an inert carrier, wherein said phenylephrine is present in said topical preparation in an amount effective to substantially reduce flow of blood from a bleeding skin wound when said topical preparation is applied to said skin wound.
In another aspect, the present invention provides a topical composition for stemming the flow of blood from a skin wound, comprising: phenylephrine; and an inert carrier.
Preferably, phenylephrine is present in the above topical preparation and composition in an amount effective to substantially stop cutaneous bleeding from minor skin wounds.
In yet another aspect, the present invention provides a method for treatment of skin wound to substantially reduce bleeding therefrom, said method comprising: applying a topical preparation comprising phenylephrine in an inert carrier to the skin wound.
Preferably, the topical preparation and composition of the present invention is further applied directly to the wound and to an area of skin surrounding the wound.
Use of the topical preparation and composition of the present invention preferably causes cutaneous bleeding from a skin wound to be substantially stopped.
In topical preparations and compositions of the present '2~54979 invention, the inert carrier is preferably selected from a group comprising organogels, hydrogels and emulsion-type semisolids.
In topical preparations and compositions of the present invention, phenylephrine comprises from about 0.5% to 50% by weight of the preparation, preferably in the form of phenylephrine hydrochloride.
BRIEF DESCRIPTION OF THE DRAWINGS
Further aspects and advantages of the present invention will become apparent from the following description, taken together with the accompanying drawing, in which:
Figure 1 is a sectional, schematic diagram illustrating the structure of human skin and blood circulation therein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the invention are now described with reference to Figure 1.
Figure 1 is a schematic diagram showing a sectional view of the structure of human skin. As shown in Figure 1, skin comprises an upper epidermis 10 which contains layers of skin c~lls and provides the body with an outer protective barrier.
Under the epidermis 10 is the dermis 12, which contains the nutritive blood vessels of the skin. Figure 1 illustrates these nutritive vessels as comprising arteries 14, veins 16 and capillaries 18.
Under the dermis 12 is the subcutaneous layer 20 which contains the venous plexus 22, shown in Figure 1 as an intricate network of blood vessels.
The arteries 14 of the dermis 12 communicate with the venous plexus 22 of the subcutaneous tissue 20 by means of AV
anastomoses 24.
As discussed above, the blood vessels 14, 16 and 18 of the 21~, ~ 9 7 ~
dermis 12 and the AV anastomoses 24 have alpha-adrenergic receptors which may be caused to constrict by sympathomimetic agents, thereby restricting or cutting off blood flow to and/or in the blood vessels 14, 16 and 18 of the dermis 12 and between the arteries 14 and the venous plexus 22.
In the topical preparation of the present invention, phenylephrine, or (R)-3-hydroxy-alpha-[(methylamino)methyl]
benzenemethanol, is applied to the skin and is believed to stimulate adrenergic alpha receptors in the AV anastomoses 22 and the nutritive vessels 14, 16 and 18, thereby causing vasoconstriction of the AV anastomoses 22, and the blood vessels 14, 16 and 18 in the dermis 12.
When applied to the skin in the vicinity of a skin wound, the topical preparation of the present invention substantially reduces, and preferably completely stops, bleeding from the wound.
The term "skin wound" as used herein refers to wounds which penetrate the upper epidermis 10 and cause damage to blood vessels 14, 16 and 18 in the dermis, resulting in the flow of blood from the wound. A skin wound may also damage the AV anastomoses 24 and the venous plexus 22 of the subcutaneous layer 20. Types of skin wounds include cuts, punctures and scrapes. Preferably, the topical preparation of the present invention is used on skin wounds of a minor nature.
Preferably, the topical preparation according to the present invention may be used to substantially reduce or completely stop cutaneous bleeding from a minor skin wound.
The term "cutaneous bleeding" refers to blood flow from the blood vessels 14, 16 and 18 of the dermis 12.
Preferably, the topical preparation of the present invention is used of skin wounds of humans, although it may be used on other mammals such as dogs.
To stop or substantially reduce bleeding, the topical preparation of the present invention is applied in the vicinity of the wound, meaning the wound itself and the skin immediately surrounding the wound.
Phenylephrine is the active ingredient of the topical ~15~979 preparation of the present invention, causing vasoconstriction of the blood vessels in the vicinity of the wound, thereby substantially reducing or completely stopping bleeding from the wound.
s The stoppage of blood flow by the topical preparation of the present invention can be of great value in preventing substantial loss of blood from a wound.
The topical preparation according to the present invention comprises a vasoconstricting effective amount of phenylephrine dispersed in an inert carrier. Preferably, phenylephrine is present in the topical preparation in an amount of 0.5 to 50%
by weight of the preparation. Preferably, the amount of phenylephrine in the preparation is effective to reduce or stop blood flow in less than about five minutes. More preferably, phenylephrine is present in the preparation in an amount of about 2 to about 6% w/w, with about 5% w/w being most preferred.
It is to be appreciated that preparations containing smaller concentrations of phenylephrine may preferably be used to reduce or stop cutaneous bleeding from minor skin wounds and may require a longer time to reduce or stop bleeding, whereas preparations containing higher concentrations of phenylephrine may preferably be used to stop or reduce bleeding from more serious wounds and result in faster reduction or stoppage of bleeding.
Phenylephrine is preferably present in the topical preparation in the form of a physiologically active salt, the hydrochloride being most preferred. However, it is to be understood that other forms of phenylephrine may also be suitable, such as other physiologically active salts.
Preferred forms of topical preparations include creams, ointments, lotions, shampoos, aerosols, gels and liquids.
Topical preparations according to the present invention may also be incorporated into pads or wound dressings.
The topical preparation according to the present invention is more preferably in the form of a cream or ointment. The inert carrier is preferably a base which may comprise one or 2~54979 -more compounds selected from a number of groups of substances, including organogels, hydrogels, emulsion-type semisolids and emulsified bases. A particularly preferred base comprises about 45 to 50% DermobaseTM, about 45 to 50% AquadermTM, and about 0 to 5% distilled water, the amounts being expressed in terms of percent by volume of the base.
Preferred organogels include hydrocarbon type organogels such as those selected from the group comprising petrolatum and mineral oil-polyethylene gels; animal and vegetable fats such as those selected from the group comprising lard, hydrogenated vegetable oils and theobroma oil; soap base greases such as those selected from the group comprising aluminum stearate and mineral oil gels; and hydrophilic organogels such as those selected from the group comprising carbowax bases and polyethylene glycol ointment.
Preferred hydrogels include organic hydrogels such as those selected from the group comprising pectin paste and tragacanth jelly, and inorganic hydrogels such as those selected from the group comprising bentonite gels and colloidal magnesium aluminum silicate gels.
Preferred emulsion-type semisolids include water-in-oil emulsifiable bases and oil-in-water emulsifiable bases selected from the group comprising hydrophillic petrolatum, wool fat, and anhydrous Tween base (white petrolatum, stearyl alcohol, glycerine and tween 60). Preferred emulsion-type semisolids also include emulsified bases such as water-in oil emulsified bases and oil-in water emulsified bases, such as those selected from the group comprising hydrous wool fat, rose water ointment, hydrophillic ointment and vanishing cream.
A preferred method of preparing a topical phenylephrine preparation according to the present invention comprises reducing phenylephrine to an impalpable powder by levigating it with an equal amount of water. The base in then added incrementally using geometric dilution using a spatula on a hard surface (such as an ointment pad).
A number of trials were conducted to test the efficacy of topical preparations of the present invention in humans and 2 1 ~ ~ .9 7 ~
other mammals. The results of some of these trials are presented in the following examples, in which the subjects are human unless otherwise indicated.
Example 1 Subject: Male Age Range: 36-50 Location(s) of Laceration(s): Neck, chin.
Type(s) of Laceration(s): Cuts from shaving.
Number of Applications: 8 Form of Topical Preparation: Cream containing 5% w/w phenylephrine hydrochloride.
Time Required to Stop Bleeding: Stopped immediately after application.
Side Effects: None.
Example 2 Subject: Male Age Range: 36-50 Location(s) of Laceration(s): Hands and face.
Type(s) of Laceration(s): Cuts from shaving and skinned knuckles resulting in detachment of a flap of skin.
Number of Applications: 5 Form of Topical Preparation: As in Example 1.
Time Required to Stop Bleeding: 10-20 seconds.
Side Effects: None.
Example 3 Subject: Male Age Range: 26-35 Location(s) of Laceration(s): Face.
Type(s) of Laceration(s): Cuts, close to surface.
~1~4~7~
g Number of Applications: 10-15 Form of Topical Preparation: As in Example 1.
Time Required to Stop Bleeding: 5-10 seconds.
Side Effects: None.
Example 4 Subject: Female Age Range: 26-35 Location(s) of Laceration(s): Leg.
Type(s) of Laceration(s): Cut, close to surface.
Number of Applications:
Form of Topical Preparation: As in Example 1.
Time Required to Stop Bleeding: 30-60 seconds.
Side Effects: None.
Example 5 Subject: Male Age Range: 51-65 Location(s) of Laceration(s): Face and neck.
Type(s) of Laceration(s): Shaving lacerations.
Number of Applications: 10 Form of Topical Preparation: As in Example 1.
Time Required to Stop Bleeding: 1 minute.
Side Effects: None.
Comments: Subject takes aspirin daily as a blood thinner.
Example 6 Subject: Male Age Range: 36-50 Location(s) of Laceration(s): Face and hands.
Type(s) of Laceration(s): Cuts from shaving, lacerations to hand.
Number of Applications: 50 Form of Topical Preparation: As in Example 1.
2 1 ~ 3 Time Required to Stop Bleeding: 1 minute for facial cuts; 3-5 minutes for deeper hand cuts.
Side Effects: Moisturization of skin.
Example 7 Subject: Male Age Range: 36-50 Location(s) of Laceration(s): Face.
Type(s) of Laceration(s): Scrapes.
Number of Applications: 3 Form of Topical Preparation: Ointment containing 5%
w/w phenylephrine hydrochloride.
Time Required to Stop Bleeding: Short time.
Side Effects: None.
Example 8 Subject: Male Age Range: Under 25 Location(s) of Laceration(s): Face and scalp.
Type(s) of Laceration(s): Puncture wounds, lacerations up to 1 cm long, shaving cuts, bleeding pimples.
Number of Applications: 12 Form of Topical Preparation: As in Example 7.
Time Required to Stop Bleeding: Less than 1 minute.
Side Effects: Temporary whitening of skin in area around a pimple to which preparation was applied.
Example 9 Subject: Male dog ~497g Age Range: --Location(s) of Laceration(s): Scrotum.
Type(s) of Laceration(s): Surface abrasion with slow seepage of blood.
Number of Applications: 3 Form of Topical Preparation: Liquid containing 3% w/w phenylephrine hydrochloride.
Time Required to Stop Bleeding: 3 minutes.
Side Effects: Nothing obvious.
Example 10 Subject: Dogs Age Range: --Location(s) of Laceration(s): Feet, ear flap.
Type(s) of Laceration(s): Toenails cut too short, blood vessel exposed "end-on"; puncture and cut in ear flap.
Number of Applications: 4-5 Form of Topical Preparation: Ointment and liquid containing 4-5~ w/w phenylephrine hydrochloride.
Time Required to Stop Bleeding: Bleeding not stopped.
Side Effects: None.
Example 11 Subject: Male Age Range: Under 25 Location(s) of Laceration(s): Neck.
Type(s) of Laceration(s): Cut, close to surface.
Number of Applications: 5 Form of Topical Preparation: As in Example 1.
21~4979 Time Required to Stop Bleeding: 1-2 minutes.
Side Effects: None.
Example 12 Subject: Male Age Range: 26-35 Location(s) of Laceration(s): Legs.
Type(s) of Laceration(s): Scrapes, abrasions.
Number of Applications: 10 Form of Topical Preparation: As in Example 7.
Time Required to Stop Bleeding: 30-40 seconds.
Side Effects: None.
Example 13 Subject: Female Age Range: 26-35 Location(s) of Laceration(s): Hand.
Type(s) of Laceration(s): Cut, close to surface.
Number of Applications:
Form of Topical Preparation: As in Example 1.
Time Required to Stop Bleeding: Few minutes.
Side Effects: Burning.
Example 14 Subject: Male Age Range: 26-35 Location(s) of Laceration(s): Legs.
Type(s) of Laceration(s): Scrapes, abrasions Number of Applications: 10 Form of Topical Preparation: As in Example 7.
Time Required to Stop Bleeding: 30-40 seconds.
Side Effects: None.
~1~4979 Example 15 Subject: Male Age Range: 36-50 Location(s) of Laceration(s): Neck.
Type(s) of Laceration(s): Shaving cut.
Number of Applications:
Form of Topical Preparation: As in Example 1.
Time Required to Stop Bleeding: Less than 1 minute.
Side Effects: N/A.
The results of the above examples are generally favourable, with bleeding generally being stopped within a few minutes and few side effects being reported. All human subjects reported that they would use the product again, and most reported that the topical preparation of the present invention is superior to other products on the market to stop bleeding.
Although the invention has been described with reference to certain preferred embodiments, it is to be understood the invention includes all embodiments which are within the scope of the following claims.