Diisopropylphosphonoalkanes as topical medicaments for treatment of ocular diseases

Abstract

The present invention relates to a method of treating an ocular disease in a subject in need thereof. The method comprises administering to the subject a composition comprising a therapeutically effective amount of a 1-diisopropyl-phosphino-alkane (DIPA) compound. The DIPA compound is a compound selected from the group consisting of DIPA-1-7, DIPA-1-8, and DIPA-1-9. Eye diseases include blepharitis and conjunctivitis.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. application No. 17 / 803,311, filed on May 3, 2022, the entire contents of which are referenced and incorporated herein. Technical Field

[0001] The present invention relates generally to the field of therapeutic compounds. More specifically, the present invention relates to certain diisopropylphosphonoalkane (hereinafter referred to as "DIPA compounds"), such as DIPA-1-5, DIPA-1-6, DIPA-1-7, DIPA-1-8, DIPA-1-9 and DIPA-1-10 described herein, which are useful in treating skin symptoms and diseases (e.g., skin diseases). Background Art

[0002] Examples of symptoms include abnormal sensations such as irritation, burning, itching or pain, collectively referred to as skin paresthesias. Examples of inflammatory skin diseases include atopic dermatitis, contact dermatitis, genital dermatitis, lichen sclerosus, blepharitis, conjunctivitis, psoriasis and seborrheic dermatitis. The skin is also a source of pruritus (itching) when the skin function is disturbed. Skin itching occurs in conditions such as urticaria, cholestasis, renal dialysis patients, psychogenic disorders, psoriasis, dermatitis and eczema. The present invention also relates to pharmaceutical compositions comprising these compounds, and the use of these compounds and compositions in treatment.

[0003] The skin is the largest organ in the human body and consists of three layers: the epidermis, dermis and subcutaneous layer. The outermost layer, the epidermis, is only about 1 mm thick and densely permeated with nerve endings. The epidermis produces epidermal cells that form the stratum corneum, a layer of dead cells that is impermeable to water. The self-renewal period of the epidermis is about 1.5 months. When the skin is injured, the main symptoms of inflammation are heat, redness, swelling and pain. The injured tissue produces sensations of irritation, burning, itching and pain, collectively known as paresthesia. Itch or itch is a sensation that causes the urge to scratch and is a troublesome symptom of skin dysfunction. About 80% of patients who visit dermatology clinics complain of itching.

[0004] Cooling the body surface can refresh the senses, relieve discomfort, reduce pain, reduce itching, and inhibit inflammation. Cooling intensity can be ranked from refreshing cool, chilly, cold, icy, to painfully cold. Chemicals that do not normally change tissue temperature. Menthol is an example of a chemical coolant, but has limited use as an analgesic or anti-itch agent because it is irritating and has a short duration of action. The development of new anti-itch coolants has been hampered by the stratum corneum, which is a strong barrier to drug penetration to epidermal nerve endings.

[0005] The cloning of TRP channels about 25 years ago (1998 to 2002) increased our understanding of the neural circuits underlying cutaneous thermosensation and paresthesia. This work was recognized with the 2021 Nobel Prize awarded to David Julius and Ardem Patapoutian, the pioneers of this research. The language used to describe skin pathologies is now more precise, and new drugs are being designed to target specific TRP receptors on nerve endings to treat paresthesia and itch.

[0006] 1-Dialkylphosphonoalkanes [DAPA] are solvent-like molecules that require several (1 to 3) steps to synthesize. They are also known as trialkylphosphine oxides or dialkylphosphonoalkanes. When the two alkyl groups in DAPA are isopropyl, the abbreviation of DAPA becomes DIPA [diisopropylphosphonoalkanes].

[0007] Rowsell and Spring [Phosphine oxides having a physiological cooling effect. U.S. Patent 4,070,496. January 24, 1978], describe a series of phosphine oxides having a physiological cooling effect on the skin and oral cavity. See the table in columns 3 and 4 therein. Ten of the compounds shown therein (Table 1) have an isopropyl group (shown as iso-C3H7). None of these compounds contain two isopropyl groups. Siddall et al. [Simplified preparation of certain trisubstituted phosphine oxides. Journal of Chemical Engineering Data 10:303-305, 1965] reported the synthesis of 1-diisopropyl-octane [DIPA-1-8], but Siddall et al. did not test the biological activity of the molecule. Summary of the invention

[0008] In the present discovery, it was noted that the structure of certain 1-dialkylphosphonoalkanes (DAPA) was modified into 1-diisopropylphosphonoalkanes (DIPA) analogs, resulting in agents that strongly induced a "dynamic cooling" sensation when applied to the skin. The 1-diisopropylphosphonoalkanes described herein are referred to as "DIPA compounds" or "DIPAs." DIPA compounds do not affect tissue temperature, but are able to relieve discomfort and itching from skin lesions. DIPA's unusual properties include water solubility and ease of formulation, the ability to penetrate intact skin (e.g., face, eyelids, and even the surface of the eyeball) to reach targets in the epidermis, rapidly initiate an anti-itch effect, and continue to effectively treat itching after weeks of use without losing activity. This sensation of relief from discomfort and itching is referred to as a "cooling sensation," and proposed neural circuits for the mechanism of action of DIPA such as Figure 1 shown.

[0009] New clinical trial data were presented showing that a cooling sensation can relieve urticaria and scalp itching. Additional data demonstrated the effectiveness of DIPA for itching in cholestasis, lichen sclerosus, blepharitis, and conjunctivitis.

[0010] Furthermore, Applicants have unexpectedly discovered that the DIPA compounds described herein are also effective in treating ocular disorders such as dry eye symptoms, blepharitis, or conjunctivitis (eg, allergic conjunctivitis or non-infectious conjunctivitis).

[0011] Figure 1 It is described how DIPA compounds reduce the discomfort in skin diseases, a mechanism known as "cooling sensation". Noxious stimuli activate small diameter C fibers in peripheral receptive areas, transmitting signals that produce the discomfort sensation. Application of the DIPA TRPM8 agonist to the receptive areas activates larger myelinated Aδ fibers that transmit cooling signals (≤25°C). These signals are modality specific. The cell bodies of the primary afferent neurons are located in peripheral ganglia (DRG = dorsal root ganglia or cranial ganglia). Nociceptive and cooling afferent signals are integrated in the spinal cord and brainstem nuclei. Cooling sensation occurs when DIPA-induced TRPM8 signaling reduces the discomfort of nociceptive sensation.

[0012] The skin is a common site of injury. The main symptoms of the skin's response to injury (inflammation) are heat, redness, swelling and pain. Over time, injured tissue can develop irritation, burning, itching and pain, collectively known as discomfort. The DIPA molecule relieves the symptoms of discomfort through dynamic cooling. This relief is known as the "cooling sensation."

[0013] The cloning of sensory-transmitting TRP channels has revolutionized the understanding of the neural circuits underlying the sensation of heat and discomfort. This work was awarded the Nobel Prize in 2021 to David Julius and Ardem Patapoutian, the pioneers of this research. It is now possible to visualize specific TRP receptors on nerve endings and rationalize drug mechanisms of action. The emerging view is that specialized TRPM8 nerve fibers transmit cooling signals. Cooling sensations (receptors for ≤25°C) are anatomically and modality-specific, with their own preferred circuits and cables. TRPM8-mediated cooling induces a “cooling sensation” and counteracts discomfort. Neural pathways for cooling and discomfort need not overlap, but preferably originate from the same dermatome. Signals converge in the spinal cord or brainstem nuclei. Thus, for example, a cooling signal from a TRPM8-receptive area of ​​the labia can suppress labial itch. Transmission is via the pudendal nerve from the dermatomes of the sacral plexus into the spinal cord. Figure 1 The mechanism and neural circuitry are described.

[0014] In layman's terms, the concept of DIPA treatment is like placing a mini air conditioner on injured tissue. The unusual properties of the DIPA molecule are water solubility and the ability to penetrate the skin cell layers to reach the receptive targets underneath. The target of delivery is TRPM8. When activated, TRPM8 transmits a cooling sensation. Central integration of these signals relieves the discomfort. By relieving discomfort, DIPA also has a disease-modifying effect. The patient feels better, sleeps better, and interrupting the itch-scratching allows tissue to heal. Clinical data supporting these observations are presented. The water solubility of the DIPA compound at therapeutically effective concentrations facilitates the formulation of the compound for TRPM8 delivery.

[0015] Another aspect of the present discovery relates to pharmaceutical compositions comprising one or more DIPA compounds, as described herein, and a pharmaceutically acceptable carrier or diluent. Particularly preferred embodiments include one or more DIPA compounds and a delivery agent carrying the one or more compounds, wherein the delivery agent is suitable for topical delivery. These preparations, as described herein, can be used in methods of treating the human or animal body, for example, in methods of treating disease [e.g., ocular disease, such as dry eye symptoms, pain, itching, blepharitis, or conjunctivitis (e.g., allergic conjunctivitis or non-infectious conjunctivitis)]. For example, a preferred embodiment for relieving labia pruritus is a topical 1% DIPA-1-8 solution in water or saline or a 0.5% gel.

[0016] Therefore, the present invention provides a method for treating discomfort caused by skin diseases or eye diseases, which is suitable for a subject in need of treatment. The method comprises topically applying a liquid or semi-liquid composition containing a therapeutically effective amount of one or more compounds of Formula 1 to the skin of the subject. Formula 1 wherein R is n-hexyl, n-heptyl, n-octyl or n-nonyl.

[0017] In some embodiments, the compound having the general formula 1 is a 1-diisopropylphosphonoalkane (DIPA) compound, wherein R is n-hexyl, n-heptyl, n-octyl, or n-nonyl.

[0018] In certain embodiments of the present invention, the DIPA compound is selected from the following compounds.

[0019] In some embodiments, administration is topical administration.

[0020] In some embodiments, the composition is applied to the surface of the eye, the skin surrounding the eye, the eyelid, or other part of the face of the subject.

[0021] In some embodiments, the composition is a liquid or semi-liquid composition suitable for concentrated delivery of a DIPA compound to the surface of the eye of a subject.

[0022] In some embodiments, the composition is a liquid, with water or isotonic saline as the solvent.

[0023] In some embodiments, the DIPA compound is dissolved or present in micellar form in the composition.

[0024] In some embodiments, the concentration of the DIPA compound is 0.5-20 mg / mL.

[0025] In some embodiments, the composition is a liquid composition comprising the DIPA compound at a concentration of 0.5-5 mg / mL or 1-5 mg / mL.

[0026] In some embodiments, the eye disease is blepharitis or conjunctivitis (eg, allergic conjunctivitis or non-infectious conjunctivitis).

[0027] In other embodiments, the eye disorder is itching or pain in the eye or in the area of ​​skin surrounding the eye.

[0028] In some embodiments, administration of the formulations of the methods of the present invention is topically administered to the eyelid or another area of ​​skin surrounding the eye of a subject.

[0029] In some embodiments, the formulation is administered at least once a day or at least twice a day.

[0030] In some embodiments, the formulation is administered for at least one week.

[0031] In some embodiments, administration of the formulation for treating an ophthalmic condition is via a wipe, wet tissue, eye drop device, or ointment tube.

[0032] The liquid or semi-liquid compositions used in the methods of the present invention, upon topical application, penetrate the skin of a subject and are effective in reducing or eliminating inflammation or infection at the site of administration.

[0033] Another aspect of the invention is to use a compound of formula 1 (e.g., a DIPA compound such as DIPA-1-6, DIPA-1-7, DIPA-1-8 or DIPA-1-9) to manufacture a drug for topical administration to treat eye diseases, such as administration to the eyelids or skin area around the eyes of a subject in need of treatment.

[0034] Examples of eye disorders include dry eye symptoms, blepharitis, conjunctivitis (eg, allergic conjunctivitis or noninfectious conjunctivitis), itching or pain in the eye or in the area of ​​skin surrounding the eye. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The novel features of the invention are particularly pointed out in the appended claims.The features and advantages of the invention may be better understood by referring to the following detailed description and accompanying drawings which illustrate examples of the application of the principles of the invention.

[0036] Figure 1 It is described how DIPA compounds reduce the discomfort in skin diseases through a mechanism called "cooling sensation". Noxious stimuli activate small diameter C fibers in peripheral receptive areas, transmitting signals that produce the discomfort sensation. Application of the DIPA TRPM8 agonist to the receptive areas activates larger myelinated Aδ fibers that transmit cooling signals (≤25°C). These signals are modality specific. The cell bodies of the primary afferent neurons are located in peripheral ganglia (DRG = dorsal root ganglia). Nociceptive and cooling afferent signals are integrated in the spinal cord and brainstem nuclei. The cooling sensation occurs when DIPA-induced TRPM8 signaling reduces the discomfort of nociceptive sensation.

[0037] Figure 2 Illustration of a human face showing the innervation of the cheek skin by the zygomaticofacial nerve (ZFN) and the infraorbital nerve (ION). The receptor fields of these nerve endings were used to test compounds applied to the cheek skin. Diagram adapted from a study by Hwang et al. [Cutaneous innervation of the lower eyelid. J Craniofacial Surg 19:1675-1677, 2008]. Figure 3 The cooling sensation induced by topical application of different concentrations of DIPA-1-8 to the skin above the zygomatic bone is shown. The cooling activity can be measured as the area under the intensity / duration curve (AUC) or the time of half-maximal effect (T-1 / 2) using the GraphPad Prism software package. The graph shows the dose-response curve of DIPA-1-8 compound at 0.5, 1 and 2% (5, 10 and 20 mg / mL dissolved in distilled water).

[0038] Figure 4 The cooling sensation induced by topical application of different compounds to the skin above the cheekbones is shown. The cooling activity is expressed as the area under the intensity / duration curve (AUC) using the GraphPad Prism software package. The tested concentration was 2% (20 mg / mL in distilled water). The diisopropyl analog is DIPA 3,3-X and the isopropyl, sec-butyl analog is Mixed 3,4-X. "X" refers to the number of carbon atoms on the third alkyl group. It can be seen that the mixed analog is much less active on the cheek skin compared to the corresponding diisopropyl analog.

[0039] Figure 5Graph of the logarithmic change in fluorescence response (Δ ratio 340 / 380) in TRPM8 transfected cells as a function of test compound concentration (in μM) for DIPA-1-7 (black circles), 3,4-7 (open squares), or 3,4-6 (open triangles). These experiments were performed by Andersson et al. at King's College, UK, using methods described by him ["Modulation of the cold-activated channel TRPM8 by lysophospholipids and polyunsaturated fatty acids." Journal of Neuroscience 27(12):3347-3355, 2007].

[0040] Figure 6 Demonstrates a method for estimating the in vivo transdermal activity of specific DIPA compounds, where 20 μL of the compound is applied with a micropipette to the center of a circle surrounded by the cream on the abdominal skin of anesthetized rats. The shaking frequency is calculated within 40 minutes after topical application. It can be seen that the specific compounds DIPA-1-5, DIPA-1-6, and DIPA-1-7 induce strong shaking, but this phenomenon is not seen with the other analogs.

[0041] Figure 7 The flux of DIPA-1-7 and DIPA-1-9 through excised hairless mouse skin in vitro is shown. The test chemicals dissolved in the gel were placed in an incubator for 8 hours and the amount of chemicals permeated was measured by high pressure liquid chromatography equipped with a refractive index detector. These tests were performed by Professor Choi of Chusan University in South Korea. The flux of 1-7 was approximately 5 times that of 1-9. Standard enhancers designed to increase permeation, such as a propylene glycol-oleyl alcohol mixture (50:50) or Lauroglycol 90, added to the 1-7 gel reduced the permeation by approximately 50%, indicating the importance of water solubility for permeation. DETAILED DESCRIPTION

[0042] Reference is made to specific features and / or non-limiting embodiments of the present invention. It should be understood that the invention disclosed in this specification includes all possible combinations of all such specific features. For example, when a specific feature is disclosed in the context of a specific aspect or embodiment, or in a specific claim, that feature may also be used in combination with other specific aspects and embodiments, as well as in the context of the present invention generally, to the extent possible.

[0043] The present discovery relates to certain compounds (DIPA compounds described herein) that, when delivered to the skin, are capable of selectively and potently inducing a "dynamic cooling" or cooling sensation for at least several hours. The dynamic cooling can be repeated without significant reduction in effect and can last throughout the day. Therefore, these compounds have applications in treating skin complaints, particularly skin irritation, itching and pain.

[0044] In one aspect, the present invention provides a method of treating an eye disease in a subject in need of such treatment. The method comprises topically applying to the skin of the subject a liquid or semi-liquid composition comprising a therapeutically effective amount of one or more compounds of Formula 1. Formula 1 wherein R is n-heptyl, n-octyl or n-nonyl.

[0045] In some embodiments, the method comprises administering to the subject a composition comprising a therapeutically effective amount of a 1-diisopropylphosphonoalkane (DIPA) compound.

[0046] The compositions described herein can be directly administered to human patients, or mixed with other active ingredients in pharmaceutical compositions, such as combination therapy, or carriers, diluents, excipients or combinations thereof. Appropriate formulations depend on the selected route of administration. Administration and formulation techniques are known to those skilled in the art.

[0047] As used herein, "carrier" refers to a component that facilitates the entry of a compound into cells or tissues. For example, dimethyl sulfoxide (DMSO), ethanol (EtOH) or PEG400 are commonly used carriers that help many organic compounds enter cells or tissues of a subject.

[0048] As used herein, a "diluent" refers to an ingredient that lacks pharmacological activity but may be pharmaceutically necessary or desirable in a pharmaceutical composition. For example, a diluent may be used to increase the mass of a potent drug that is too small to manufacture and / or administer. It may also be a liquid used in a drug that is administered by injection, oral administration, or inhalation. A common form of diluent in the art is a buffered aqueous solution, such as unrestricted phosphate-buffered saline, which mimics the composition of human blood.

[0049] As used herein, an "excipient" refers to an inert substance added to a pharmaceutical composition to provide, without limitation, bulk, consistency, stability, binding capacity, lubrication, disintegration capacity, etc., to the composition. A "diluent" is a type of excipient.

[0050] As used herein, a "therapeutically effective amount" refers to a sufficient amount of the DIPA compound at a reasonable benefit / risk ratio applicable to any medical treatment. However, it is understood that the total daily dose of the DIPA compound may be adjusted by the attending physician in appropriate circumstances. The specific therapeutically effective dosage level for any particular subject will depend on a variety of factors, including the disease being treated and the severity of the disease; the specific composition used, the age, weight, general health, sex and diet of the subject; the time of administration, route of administration and rate of excretion of the DIPA compound; the duration of treatment; drugs used in conjunction or coincidentally with the DIPA compound; and other factors well known in the medical art. For example, it is well known in the art to start doses of the compound at levels below that required to achieve the desired therapeutic effect and to gradually increase the dosage until the desired effect is achieved. In addition, a "therapeutically effective amount" is an amount that elicits the biological or medical response of a tissue, system or subject that is being sought by the researcher or clinician, particularly to elicit some desired therapeutic or preventive effect to combat an eye disease.

[0051] Those skilled in the art recognize that even if the condition is not completely eradicated or prevented, as long as it or its symptoms and / or effects are partially improved or alleviated in the subject, it can be considered to be "effective" in treatment. Various indicators for determining the effectiveness of a method for improving eye disease are well known to those skilled in the art.

[0052] As used herein, the terms "treat," "treatment," "therapeutic," or "therapy" do not necessarily imply a complete cure or elimination of a disease or condition. Any degree of alleviation of any unwanted signs or symptoms of a disease or condition may be considered a treatment and / or therapy. In addition, treatment may include actions that may worsen a patient's overall well-being or appearance.

[0053] In certain embodiments of the present invention, the DIPA compound is selected from the following compounds.

[0054] DIPA compounds are water soluble and quickly produce an intense, cooling sensation on the skin. The chemical characteristics of DIPA compounds are minimal reactive alkyl side chains adjacent to the phosphine oxide, allowing greater exposure of the polar phosphine oxide group to water, increasing its water solubility.

[0055] In some embodiments, the administration is topical administration. As used herein, the term "topical administration" refers to delivery to a surface of the body in contact with air.

[0056] In some embodiments, the composition is administered to the surface of the eye of a subject.

[0057] The surface of the eye includes the outer layer of the cornea, tears, conjunctiva, and eyelid margins. This part of the eye is most commonly injured and develops eye disease because it is directly exposed to the environment.

[0058] In some embodiments, the composition is a liquid or semi-liquid composition suitable for concentrated delivery of a DIPA compound to the surface of the eye of a subject.

[0059] The term "focused delivery" refers to achieving the desired effect: avoiding excessive irritation and applying gentle cooling. The receptor targets of DIPA compounds at nerve endings are embedded in layers of epithelial cells. The epidermis is only about 1 mm thick, but denatured proteins in many dead cell layers (stratum corneum) prevent agonist molecules from entering the nerve endings. The heels are the thickest barrier, with 86 cell layers, followed by the palms and then the backs of the hands. The eyelids are the thinnest, with 4 to 8 cell layers. The limbs, arms and legs, and the trunk (back) have thicker surfaces. The scalp is in the middle. These differences are important for drug action. For the eyelids, the compounds and other composition ingredients must be carefully selected to achieve the desired effect: avoiding excessive irritation and applying gentle cooling.

[0060] In some embodiments, the composition is a liquid, with water or isotonic saline as the solvent.

[0061] In some embodiments, the concentration of the DIPA compound is 0.5-20 mg / mL.

[0062] In some embodiments, the composition is a liquid composition comprising the DIPA compound at a concentration of 0.5-5 mg / mL or 1-5 mg / mL.

[0063] In some embodiments, the eye disease is blepharitis or conjunctivitis.

[0064] Blepharitis is an inflammation of the eyelids. It is a common eye condition that makes the eyelids red, swollen, inflamed, and itchy. It can cause dandruff-like flakes on the eyelashes. Blepharitis usually affects both eyes at the edge of the eyelids. Blepharitis is usually caused by a blockage in the small oil glands near the base of the eyelashes, causing irritation and redness. Several diseases and conditions can cause blepharitis.

[0065] Conjunctivitis (pink eye) is an inflammation or infection of the clear membrane lining the eyelids (conjunctiva), which covers the white part of the eyeball. When the small blood vessels in the conjunctiva become inflamed, they become more visible. This is what causes the white part of the eye to appear red or pink. Pink eye is often caused by a bacterial or viral infection, an allergic reaction, or, in infants, by tear ducts that do not open completely. Although pink eye may cause irritation, it rarely affects vision. Treatment can help relieve the discomfort of pink eye.

[0066] In some embodiments, the conjunctivitis is allergic conjunctivitis.

[0067] Allergic conjunctivitis is a localized allergic condition of the eyelids (blepharitis) and conjunctiva. This condition can significantly interfere with quality of life due to persistent ocular itching, which in severe cases can potentially impair visual function. Subcategories of allergic conjunctivitis include a) seasonal and perennial allergies (IgE-mediated allergies), b) atopic keratoconjunctivitis (associated with atopic dermatitis), c) vernal keratoconjunctivitis (a subset of immune disorders, 50% associated with IgE), d) contact blepharoconjunctivitis (similar to contact dermatitis, such as the use of eye makeup) and e) giant papillary conjunctivitis (associated with contact lens use). The common denominator of the symptoms is ocular itching.

[0068] In some embodiments, the administering is topical administration to the eyelid of the subject.

[0069] In some embodiments, administration is at least once a day.

[0070] In some embodiments, administration is at least twice a day. In some embodiments, administration is once in the morning and once in the evening.

[0071] In some embodiments, the administration continues for at least one week.

[0072] In some embodiments, administration is by swabbing.

[0073] The composition can be provided in suitable packaging and / or in a suitable container. For example, the composition can be provided as a swab, wipe, pad or towel (e.g., suitably sealed in packaging) with a DIPA compound or a composition comprising a DIPA compound.

[0074] Similarly, the composition may be provided as an aerosolized spray from a pressurized container.

[0075] Additionally, the composition can be provided as a manually activated sprayer (e.g., with an appropriate orifice) connected to a reservoir containing a DIPA compound or a composition containing a DIPA compound, for example, capable of delivering a unit volume (e.g., 0.05 to 0.15 ml), for example, to the skin surface. definition

[0076] Unless otherwise defined, all technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art. Unless otherwise indicated, all patents, applications, published applications, and other publications cited herein are incorporated by reference in their entirety. If a term has multiple definitions herein, the definition in this section shall prevail unless otherwise indicated.

[0077] Allergic conjunctivitis. Approximately 15% of the world's population suffers from allergic diseases involving the eye. (Leonardi A. Allergic and allergic mediators in tears. Exp Eye Res. 2013; 117: 106-17). Allergic conjunctivitis is a localized allergic condition of the eyelids (blepharitis) and conjunctiva. This condition can significantly interfere with quality of life due to persistent ocular itching, and in severe cases can potentially impair visual function. Subcategories of allergic conjunctivitis include a) seasonal and perennial allergies (IgE-mediated allergies), b) atopic keratoconjunctivitis (associated with atopic dermatitis), c) vernal keratoconjunctivitis (a subset of immune disorders, 50% associated with IgE), d) contact blepharoconjunctivitis (similar to contact dermatitis, such as the use of eye makeup) and e) giant papillary conjunctivitis (associated with the use of contact lenses). Conjunctivitis may occur in the absence of an allergic etiology (e.g., exposure to chemical irritants). The common denominator of the symptoms is ocular itching.

[0078] Atopic dermatitis (eczema) is an inflammatory disease of the skin. All areas of the skin may become itchy and inflamed. Lesions, including scratch marks, are often prominent in the bends of the elbows and knees, probably because these areas sweat more. Many people with atopic dermatitis also have allergic rhinitis and asthma. Children and young adults experience symptoms more frequently than adults. Recently, the U.S. FDA approved two new drugs for the treatment of atopic dermatitis: dupilumab (a monoclonal antibody) and crisaborole (an ointment). Both drugs have a slow onset of therapeutic action, taking more than 6 weeks. Dupilumab is very expensive for a year of treatment. Cresaborole has only modest efficacy, and it is a greasy ointment that is not favored by people with atopic dermatitis. One of the side effects of dupilumab in people with eczema is blepharitis, which can be relieved by using DIPA, an eye wipe.

[0079] Cholestatic pruritus. In certain systemic diseases, such as cholestasis, renal failure and renal dialysis, liver failure, and lymphoma, there are blood-borne pruritogens that cause generalized pruritus. The exact chemical identity of these pruritogens is unknown, but they are probably bile acids in patients with liver disease and renal dialysis. The pruritus is intense and causes great distress to the patient. During pregnancy, some subjects also experience intense cholestatic pruritus, for which there is no known medical treatment. The pruritus is not associated with skin inflammation.

[0080] Skin diseases are diseases of the skin, nails, or hair. The skin has three layers; the epidermis, dermis, and subcutaneous layer. The epidermis includes a keratinized stratum corneum. The eyelids, cornea, tongue, and parts of the mouth are keratinized and therefore considered skin. Internal surfaces of the body, such as mucous membranes, do not have a stratum corneum. The skin is the largest organ in the human body, but the epidermis is only about 1 mm thick. The epidermis is densely populated with nerve endings. The turnover time of the epidermis, the time it takes to renew itself, is about 1.5 months. Inflammation can occur in all three layers of the skin, but itching originates primarily in the epidermis. About 80% of patients who visit dermatologists complain of itching (J. Rinaldi. The itch-scratch cycle. Dermatology, Practice and Concepts 9:90-97, 2019).

[0081] Dermatomes. Areas of the body innervated by a single spinal nerve are called dermatomes. Inputs from directly adjacent dermatomes can influence sensation in one area because of overlap in the somatotopic organization of sensory projections. This overlap of sensory inputs is called convergence. A good example of a convergent mechanism is itch and scratching in analgesia. Scratching activates mechanoreceptors to relieve itch, but scratching the exact source of the itch is not necessary. An adjacent site is sufficient.

[0082] DIPA Compounds DIPA is an abbreviation for 1-[diisopropylphosphonyl]-alkane. The third alkyl group in the molecule can be described by a number: thus, 4, 5, 6, 7, 8, 9, and 10 correspond to butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl side chains, respectively. These alkanes are in a linear or "normal [n]" configuration, with the phosphonyl group attached to the carbon chain of the third side chain in the primary or "1-" position. These compounds are also known as trialkylphosphine oxides or 1-dialkylphosphonoalkanes.

[0083] Paresthesia. Injury to the body's surface activates nerve endings that transmit signals that are interpreted by the brain as "discomfort" or "paresthesia" (a feeling that something is wrong). Examples of paresthesia include pain, irritation, itching, burning sensations, and aches. Paresthesia is a general term for discomfort that is more inclusive than words like "pain" or "itching." When there is chronic damage to the epidermis and transitional epithelium, the sensation of paresthesia can be very noticeable.

[0084] Itch-Scratch Cycle. Scratching can relieve itch, but the vicious cycle of itch-scratch can lead to more skin damage, continued inflammation, and result in scratching and destructive lichenification. The itch-scratch cycle is a well-known phenomenon in children and canine atopy, where a shield is set up to prevent the subject from scratching at sites of inflammation and itching. Itch prevents a good night's sleep, and patients with atopic dermatitis will scratch themselves vigorously even in their sleep. An effective medication should prevent itching within minutes of application and work long enough to allow the subject to fall asleep. Subjects should be instructed to apply the medication after washing, as needed, and at bedtime, as the subject may scratch after falling asleep. This is especially important in children. The medication should also break the itch-scratch cycle, thereby promoting healing.

[0085] Post-burn pruritus. During the recovery phase of a burn injury, the healing skin becomes extremely itchy. Clinically, post-burn pruritus is often unresponsive to conventional treatments. Preliminary studies have shown that DIPA-1-7 gel is effective in relieving post-burn pruritus.

[0086] The receptive field of a sensory neuron is the area in space where stimulation changes the firing of the neuron. The receptive field is determined by the distribution of the neuron's nerve endings. In the case of epithelium, the nerve endings are interlaced with the cell layer of the epithelium's basal layer. Even a receptive field of less than 1 square millimeter can completely command the brain and attention when activated by the appropriate stimulus, such as nociception or itch. Look at what happens when a sharp needle or prick comes into contact with the skin, or when a dog is bothered by flea bites.

[0087] Scalp Itch. Sensory information from the scalp, such as from the top of the head or the occipital region, is carried by branches of the trigeminal nerve and the cervical nerves (V1: ophthalmic branch of the trigeminal nerve; V2: maxillary branch of the trigeminal nerve; V3: mandibular branch of the trigeminal nerve; C2: second cervical nerve; C3: third cervical nerve). The bulbs of the hair follicles on the scalp are densely innervated. Seborrheic dermatitis is an inflammatory condition caused in part by a fungal infection. It can occur on the scalp, causing dandruff and itching. Psoriasis is another common cause of scalp itching, especially around the hairline.

[0088] TRP channels. Cation channels of the transient receptor potential (TRP) family are peripheral detectors of temperature and nociceptive and painful stimuli. These receptors on sensory neurons respond to stimuli by activating neural action potentials, which are transduced as sensations. TRPM8 receptor signals heat abstract. TRP signaling allows organisms to detect, respond to, and adjust to external stimuli.

[0089] Urticaria, also known as hives, is a disease characterized by the sudden onset of "wheals" (red areas of skin with raised and itchy bumps) that can appear anywhere on the body. The wheals can be quite large and alarming, but are not life-threatening. The trigger is usually an allergy to food, such as seafood, but there are a variety of triggers. The skin layers are intact, but it is the histamine released by mast cells in the epidermis and dermis that causes the wheals and itching. The condition can be treated with oral antihistamines and in more severe cases oral prednisone or Ig-E antibodies, but the onset of the drug effect takes about 12 hours. Urticaria is a recurrent disease that may last for more than 6 weeks in some patients (chronic urticaria). The cosmetic disruption of itchy skin and red wheals is an annoying feature of urticaria.

[0090] Vulvar anatomy and pruritus. The female genitalia includes the vulva and its outer and inner lips, called the labia majora and labia minora, respectively, and accessory structures including the urethra, vestibule, and vagina. The perineum is the area that extends from the underside of the vulva to the anus. The anogenitalia is innervated by the pudendal nerve, which transmits information about pain and other sensations to the vulva. The pudendal nerve originates from the sacral spine and travels through the pelvis, entering the vulvar region at the hip bone. Branches of the pudendal nerve include the inferior rectal nerve, perineal nerve, and dorsal clitoral nerve. These nerves provide sensory information and control urination, defecation, and orgasm. Vulvar pruritus is a common clinical condition with a variety of causes. This issue has been reviewed (Raef HS, Elmariah SB. Vulvar pruritus: a review of clinical associations, pathophysiology, and therapeutic management. Front Med. 2021;8(April):1-10), and the information is incorporated into this reference (In men, the penis is the source of pruritus). Damage and inflammation to the anogenital surfaces and structures causes paresthesias of vulvar itching and pain, usually caused by allergies, immune disorders, infection, hormonal imbalances, or trauma. Vulvodynia and clitorodynia are paresthesias that may occur in the absence of anatomical evidence of tissue damage. Lichen sclerosus is an inflammatory condition that affects the anogenital surfaces, causing severe itching. DIPA compounds

[0091] The DIPA compound in the present invention is achiral and is a 1-dialkylphosphonoalkane [(O=)PR 1 R 2 R 3 ] example, wherein R1, R2 and R3 are each an alkyl group, in particular R1 and R2 are isopropyl groups, and R3 is a linear alkyl group of 5 to 9 carbon atoms, which have the general formula of the following general formula 1. wherein R is n-pentyl, n-hexyl, n-heptyl, n-octyl or n-nonyl. Chemical synthesis

[0092] The DIPA compounds were prepared according to the following general procedure: 100 mL (23.7 g, about 200 mmol) of isopropylmagnesium chloride (or sec-butylmagnesium chloride in the case of the di-sec-butyl derivative) was obtained from Acros as a 25% solution in tetrahydrofuran (THF) in a 500 mL flask equipped with a stirring bar and carried out under nitrogen. A solution of diethylphosphonate in tetrahydrofuran obtained from Aldrich (D99234; 8.25 g, 60.6 mmol in 50 mL) was added dropwise. After about 30 minutes, the reaction mixture was heated to boiling. The reaction mixture was stirred for an additional 30 minutes, and then a solution of the appropriate n-alkyl iodide in THF (from TCI; 60 mmol in 20 mL) was added dropwise. The reaction mixture was then stirred at room temperature overnight. The reaction mixture was diluted with water, transferred to a separatory funnel, acidified with acetic acid (about 10 mL), and extracted twice with ether. The ether layer was washed with water and evaporated (RotaVap Buchi, bath temperature 40°C). The light brown oil was distilled under high vacuum. The final product was verified to be a colorless transparent liquid by mass spectrometry. The synthesis was performed by professional chemists at Phoenix Pharmaceuticals, Inc. in Burlingame, California, Uetikon Laboratories in Lahr, Germany, and Dong Wha Pharmaceuticals in Seoul, South Korea. The compounds in Table 2 are embodiments of the present invention. The following compounds (Table 3) were also prepared by this general synthesis method and are used for comparison.

[0093] The 3,4-X series is a "mixed" isopropyl-sec-butyl compound (Table 3). These compounds were synthesized by Dr. JaeKyun Lim of Dong-A Pharmaceutical using the following method. In short, as shown in the following scheme, triethylphosphonate (A) is reacted with sec-butylmagnesium bromide (B) and then hydrolyzed with dilute hydrochloric acid to give the monoalkyl compound (C). The product (C) is then reacted with isopropylmagnesium bromide (D) to give the dialkyl compound (E), which is then reacted with the appropriate alkyl iodide (F) to give the desired trialkylphosphine (G). General observations of unusual properties

[0094] DIPA compounds are colorless liquids with a density less than that of water. The preferred DIPA-1-7, DIPA-1-8, and DIPA-1-9 exert a cooling sensation on the skin paresthesias (e.g., caused by various dermatitises (e.g., atopic dermatitis or urticaria) and mucous membranes (especially DIPA-1-8 and DIPA-1-9)) and can modulate the skin paresthesias. Rowsell and Spring described similar structures in U.S. Pat. No. 4,070,496 (1978), but these structures have been dormant in the scientific literature for more than 40 years. All of the "heads" (phosphine oxide groups) of the '496 structure (Table 1) are capped with larger, more lipophilic groups. Applicants note that '496 does not include diisopropyl analogs. Applicants synthesized these analogs (which are achiral compared to the '496 structure, which has more than 95% stereoisomers). Applicants have discovered that by minimizing the two alkyl side chains to diisopropyl, the "head" of the prototype molecule is now more polar (hydrophilic) and more miscible in the polar environment of water. This increased water solubility is significant (Table 4). DIPA is at least 10 times more water soluble than the di-sec-butyl or mixed isopropyl-sec-butyl analogs. The DIPA analog can now move in the extracellular fluid and penetrate between cells to contact nerve endings in the basal lamina.

[0095] When DIPA compounds are applied to facial skin as 110 mg / mL aqueous solutions or 1% hydrogels, they cause little irritation. For some analogs, contact with periorbital or malar skin at 110 mg / mL concentrations produces a "dynamic cooling" sensation that can be felt within a minute of application. A single application can evoke this "refreshing" feeling that can offset hours of fatigue. DIPA-1-7, in particular, has a strong dynamic cooling effect.

[0096] Periorbital administration of DIPA and its related di-sec-butyl analogs can leave residues on the eyelid skin. When the eyelids become wet, such as when bathing or sweating, the residual compound can wash onto the cornea, causing stinging and irritation. This will limit the application options for eyelid skin administration of the compound, such as blepharitis and conjunctivitis. Among the compounds of Formula 1, DIPA-1-8 and DIPA-1-9 have the least residual irritation and are therefore particularly suitable for long-term treatment of ocular paresthesias. The effectiveness of DIPA-1-9 in treating patients with "dry eye syndrome" was demonstrated in Case Study 7. DIPA-1-7 is more suitable for applications where an immediate and refreshing sensory effect is required. Both DIPA-1-7 and DIPA-1-8 are suitable for treating skin paresthesias (e.g., skin irritation, itching or painful skin). DIPA-1-8 has a slightly longer duration of action than DIPA-1-7.

[0097] Compositions. One aspect of the present discovery relates to compositions (e.g., pharmaceutical compositions) comprising a DIPA compound (as described above) and a pharmaceutically acceptable carrier, diluent, or excipient. Another aspect of the present discovery relates to methods for preparing compositions comprising a mixed DIPA compound (as described above) and a pharmaceutically acceptable carrier, diluent, or excipient.

[0098] In one embodiment, the composition comprises a DIPA compound at a concentration of 0.005-2.0% weight / volume. In one embodiment, the composition is a liquid or semi-liquid composition (lotion, cream or ointment), comprising a DIPA compound at a concentration of 0.5-20 mg / mL. In one embodiment, the composition is a liquid composition, comprising a DIPA compound at a concentration of 1-5 mg / mL. In one embodiment, the composition is a liquid composition, comprising a DIPA compound at a concentration of 5-10 mg / mL. In one embodiment, the composition is a liquid composition, comprising a DIPA compound at a concentration of 10-20 mg / mL. The composition can be provided in appropriate packaging and / or in an appropriate container. For example, the composition can be provided as a swab, wipe, pad or towel (e.g., appropriately sealed in a package) carrying a DIPA compound or a composition comprising a DIPA compound. Similarly, the composition can be provided as a patch, e.g., a controlled release patch, suitable for application to the skin, e.g., the skin above the supraclavicular fossa or sternocleidomastoid muscle. Similarly, the composition can be provided as an atomized spray provided from a pressurized container. Likewise, the composition can be provided in a manually activated sprayer (e.g., with an appropriate orifice) connected to a reservoir containing a DIPA compound or a composition containing a DIPA compound, for example, capable of delivering a unit volume (e.g., 0.05 to 0.15 ml), for example, to the skin surface.

[0099] Use in the manufacture of a medicament. Another aspect of the present discovery relates to the use of a DIPA compound as described above in the manufacture of a medicament, e.g., for use in a method of treatment, e.g., for use in a method of treating a disease (e.g., a disease) as described above. In one embodiment, the medicament comprises a DIPA compound.

[0100] Another aspect of the present discovery relates to a method of treatment, e.g., a method of treating a disease (e.g., a disorder) as described above, comprising administering to a subject in need of treatment a therapeutically effective amount of a DIPA compound, as described above, preferably in the form of a pharmaceutical composition.

[0101] Diseases treated. In one embodiment (e.g., in methods of treatment, in the manufacture of a medicament, in methods of treatment), the treatment is treatment of: sensory discomfort (e.g., caused by irritation, itching, or pain); skin paresthesias; atopic dermatitis; contact dermatitis; prurigo nodularis; urticaria; miliaria rubra; lichen sclerosus; anogenital skin inflammation; acne; acneiform eruption; pruritus in the elderly, pruritus caused by cholestasis and liver disease; pruritus caused by lymphoma; pruritus caused by renal failure dialysis; seborrheic dermatitis; psoriasis; rosacea; eye pain and discomfort; pruritus during the healing process of burns.

[0102] As used herein, the term "sensory discomfort" refers to irritation, itching, pain or other paresthesias (abnormal sensations; such as burning sensations, or the presence of foreign bodies, or pins and needles) on the surface of the body. The term means activating nociceptors located at the sensory nerve endings of the body. Nociceptors are stimulated by heat, mechanical pressure, chemicals (e.g., capsaicin, acidity, pollutants, etc.), injury, inflammation and inflammatory mediators, etc. DIPA compounds such as DIPA-1-7 or DIPA-1-8 can reduce sensory discomfort and can be referred to as anti-nociceptor agents.

[0103] In one embodiment, the sensory discomfort is irritation, itching or pain. In one embodiment, the sensory discomfort is caused by skin paresthesia. In one embodiment, the skin paresthesia is skin irritation, itchy skin or painful skin. In one embodiment, the sensory discomfort is caused by atopic dermatitis. In one embodiment, the sensory discomfort is caused by canine atopic dermatitis. In one embodiment, the treatment is the treatment of skin paresthesia. In one embodiment, the treatment is the treatment of dermatitis. In one embodiment, the treatment is the treatment of atopic dermatitis. In one embodiment, the treatment is the treatment of canine atopic dermatitis. In one embodiment, the treatment is the treatment of contact dermatitis. In one embodiment, the treatment is the treatment of urticaria. In one embodiment, the treatment is the treatment of pruritus in the elderly. In one embodiment, the treatment is the treatment of pruritus caused by miliaria rubra. In one embodiment, the treatment is the treatment of pruritus caused by liver disease (cholestasis). In one embodiment, the treatment is the treatment of pruritus in dialysis patients with renal failure. In one embodiment, the treatment is the treatment of pruritus in patients with lymphoma. In one embodiment, the treatment is the treatment of paresthesia in psoriasis. In one embodiment, the treatment is the treatment of paresthesia in neurogenic / neuropathic pruritus. In one embodiment, the treatment is the treatment of paresthesia in lichen sclerosus. In one embodiment, the treatment is treatment of ocular discomfort. In one embodiment, ocular discomfort is caused by eye fatigue; eye strain; eye surgery; airborne irritants or pollutants that interact with the ocular surface; prolonged wear of contact lenses; overexposure to sunlight; conjunctivitis; conjunctivitis in atopic dermatitis patients treated with dupilumab; or dry eye syndrome. In one embodiment, the treatment is treatment of milia rubra. In one embodiment, the treatment is refreshing the skin of a human or mammal.

[0104] Treatment. In the context of treating a disease, the term "treatment" as used herein generally refers to treatment of humans or animals (e.g., in veterinary applications) in which some desired therapeutic effect is achieved, e.g., inhibiting the progression of a disease, and includes slowing the rate of progression, stopping the rate of progression, alleviating symptoms of a disease, ameliorating a disease, and curing a disease. Prophylactic treatment (i.e., prevention) is also included. For example, use with patients who have not yet developed a disease but are at risk of developing a disease is also included in the term "treatment." The term "therapeutically effective amount" as used herein refers to an effective amount of a compound in a substance, composition, or dosage form comprising the compound, commensurate with a reasonable benefit / risk ratio, that can produce some desired therapeutic effect when administered according to the desired treatment plan.

[0105] Combination therapy. The term "treatment" includes combination therapy and therapies in which two or more treatments or therapies are used in combination, e.g., sequentially or simultaneously. For example, the DIPA compounds described herein may also be used in combination therapy, e.g., with another drug. One aspect of the present discovery relates to the use of a DIPA compound as described above in combination with one or more (e.g., 1, 2, 3, 4, etc.) other therapeutic agents. The specific combination will be determined by the physician or pharmacist based on his or her general knowledge and known dosage regimens. Examples of other therapeutic agents include: anti-inflammatory glucocorticoids; analgesics; sympathomimetic amine decongestants; antihistamines; local anesthetics; ophthalmic lubricants or cleansers; sunscreen ingredients; anti-acne agents; keratolytics; hemorrhoid treatments; treatments for vulvar itching or discomfort; antibiotics; skin moisturizers; or anti-aging agents.

[0106] Route of Administration. A DIPA compound or a pharmaceutical composition comprising a DIPA compound can be suitably administered topically to a subject, e.g., as described herein. As used herein, the term "topical application" refers to delivery to surfaces of the body in contact with air, including the skin, anogenital surfaces, transitional epithelial surfaces of the orbits, lips, tip of the nose, and anus. Particularly preferred application sites are surfaces innervated by the trigeminal, cervical, and sacral nerves, including the scalp, facial skin, periorbital skin, and lips, as well as surfaces of the neck, elbows, and knees that are often associated with the pruritus of atopic dermatitis and psoriasis. Another preferred site is the scalp, which may be the site of inflammation in psoriasis and seborrheic dermatitis.

[0107] In one embodiment (e.g., in a method of treatment, in the manufacture of a medicament, in a method of treatment), treatment is performed by topical administration. In one embodiment, treatment is performed by topical administration to the skin of the skin of the face. In one embodiment, treatment is performed by topical administration to the skin around the orbit, the skin of the eyelid, the skin of the zygomatic region, the skin of the cheek, the skin of the forehead, or the scalp. In one embodiment, treatment is performed by topical administration to the skin surface of the orbit, the frontal bone, or the zygomatic region. In one embodiment, treatment is performed by topical administration to the skin surface of the anus and / or male or female genitalia. In one embodiment, treatment is performed by topical administration to the skin above the flexion of a limb, the supraclavicular fossa, or the skin of the sternocleidomastoid muscle.

[0108] Subject / patient. The subject / patient may be a mammal, e.g., a marsupial (e.g., kangaroo, wombat), a rodent (e.g., guinea pig, hamster, rat, mouse), a murine (e.g., mouse), a lagomorph (e.g., rabbit), an avian (e.g., bird), a canine (e.g., dog), a feline (e.g., cat), an equine (e.g., horse), a suid (e.g., pig), an ovine (e.g., sheep), a bovine (e.g., cow), a primate, anthropoid (e.g., monkey or ape), a monkey (e.g., marmoset, baboon), an ape (e.g., gorilla, chimpanzee, orangutan, gibbon), or a human. In a preferred embodiment, the subject / patient is a human.

[0109] Formulations. Although DIPA compounds can be administered alone in liquid form, e.g., dissolved in saline or water, pharmaceutical formulations (e.g., compositions, preparations, medicaments) can also be prepared comprising at least one DIPA compound, as described herein, together with one or more other pharmaceutically acceptable ingredients well known in the medical field, including, but not limited to, pharmaceutically acceptable carriers, diluents, excipients, adjuvants, fillers, buffers, preservatives, antioxidants, lubricants, stabilizers, dissolution promoters, surfactants (e.g., wetting agents), taste masking agents, and colorants. The formulations may also contain other active agents. Thus, the present discovery also provides pharmaceutical compositions and methods for preparing pharmaceutical compositions as described above. If formulated as discrete units (e.g., swabs, wipes, pads, towels, gels, lotions, creams, etc.), each unit contains a predetermined amount (dose) of the compound.

[0110] The term "pharmaceutically acceptable," as used herein, relates to compounds, ingredients, materials, dosage forms, etc. that are, within the scope of medical judgment, suitable for contact with the tissues of subjects (e.g., humans) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit / risk ratio. Each carrier, diluent, excipient, etc. must also be "acceptable," i.e., compatible with the other ingredients of the formulation. Suitable carriers, diluents, excipients, etc. can be found in the standard pharmaceutical literature, e.g., Remington's Materia Medica, 23rd ed., Mack Publishing Company, Easton, Pennsylvania, 2020; and Handbook of Pharmaceutical Excipients, 9th ed., 2018.

[0111] The formulation can be prepared by any method well known in the pharmaceutical field. These methods include the step of combining the compound with a carrier constituting one or more auxiliary components. Generally, the formulation is by evenly and closely combining the compound with a carrier (e.g., a liquid carrier, a fine powder solid carrier, etc.), and then, if necessary, shaping the product. The formulation can be suitably in the form of a liquid, a solution (e.g., aqueous, non-aqueous), a suspension (e.g., aqueous, non-aqueous), an emulsion (e.g., water-in-oil, oil-in-water), an elixir, a syrup, an electrotherapy agent, a mouthwash, drops, tablets (including, for example, coated tablets), granules, powders, lozenges, tablets, capsules (including, for example, hard capsules and soft capsules), sugar-coated tablets, pills, ampoules, suppositories, cotton wool, tinctures, gels, pastes, ointments, creams, lotions, oils, foams, sprays, mists or aerosols. In addition, the DIPA compound can be used as an auxiliary component in a pharmaceutical formulation or a cosmetic formulation.

[0112] Dosage. Those skilled in the art will appreciate that the appropriate dosage of DIPA compounds and compositions comprising DIPA compounds may vary from patient to patient. Determining the optimal dosage generally involves balancing the level of therapeutic effect against any risk or adverse side effects. The selected dosage level will depend on a variety of factors, including, but not limited to, the activity of the particular DIPA compound, the route of administration, the timing of administration, the duration of treatment, use in combination with other drugs, compounds and / or materials, the severity of the disease, and the patient's species, sex, age, weight, condition, general health, and previous medical history. The amount of DIPA compound and route of administration will ultimately be determined by a physician, pharmacist, veterinarian, or clinician, although the dosage is generally selected to achieve a local concentration at the site of action to achieve the desired effect without causing significant harmful or adverse side effects.

[0113] Administration can be performed once, continuously or intermittently (e.g., divided doses at appropriate intervals) during the course of treatment. Methods for determining the most effective administration and dosage are well known to experts in the field and will vary with the formulation used for treatment, the purpose of the treatment, the target cells to be treated, and the subject. The dosage level and pattern can be selected by the treating physician, veterinarian or clinician for single or multiple administrations.

[0114] Drug Delivery Targets. Epithelial cells cover the surfaces and cavities of organs throughout the body. When there are two or more layers of epithelium, it is called stratified epithelium. Historically, stratified epithelium has been divided into two major categories: keratinized stratified epithelium and non-keratinized stratified epithelium. Keratinized epithelium, such as the epidermis of the skin, has an outer dead cell layer [stratum corneum] composed of keratin, which is strong and impermeable to water. In contrast, non-keratinized stratified epithelium is located on the "soft tissues" of the body, such as the lining of the nasal and throat cavities and the surface of the esophagus. Keratinized tissue is more resistant to injury than non-keratinized tissue. Non-keratinized epithelial surfaces must be kept moist by glandular (serous and mucous) secretions to avoid drying out.

[0115] The stratum corneum (a cornified layer of dead cells) is a strong barrier to drug penetration into the neuroreceptive areas embedded in the epithelial tissue beneath the stratum corneum. The thickness of the barrier and the number of dead cell layers vary. The heels and palms have the most dead cell layers (about 82). The genitals (e.g., penis shaft) and eyelids have fewer layers (4 to 8). The facial skin has about 10 to 14 layers, and the trunk has 12 to 16 layers. The extremities have slightly more layers (about 15 more). Dermatitis often occurs on the extremities (e.g., the bends of the elbows and knees in atopic dermatitis) and psoriasis on the trunk and scalp. Hand eczema often occurs on the hands (contact dermatitis). Urticaria can occur all over the body, with wheals appearing on the trunk, neck, and buttocks.

[0116] However, the stratum corneum is not a solid brick wall, but has water pores like limestone, through which water-soluble molecules can pass between and within cells. The water transport channels within corneocytes are called aquaporins (Patel R et al. Aquaporins in the skin. Adv Exp Med Biol. 2017, 969: 173-191). The active ingredients must reach the nerve endings located in the basal layer (stratum basale) of the skin. A surprising discovery is that the DIPA compound was able to suppress paresthesia when applied to wipes in the form of an aqueous solution. A possible explanation is that DIPA is transmitted between cells through water channels, rather than passing through cells. The current local analgesic (pain-relieving) compounds that are effective for sensory discomfort in keratinized skin are high concentrations of l-menthol (36% alcohol solution) or local anesthetic gels. But these two topical drugs have problems with greasiness and irritation, as well as hypersensitivity reactions.

[0117] Topical targets for DIPA compounds are located at the nerve endings of the sensory areas of peripheral and cranial sensory nerves. For the face, the sensory areas of the ophthalmic and maxillary branches of the trigeminal nerve are the preferred target sites.

[0118] Figure 2is an illustration of a human face showing the innervation of the cheek skin by the zygomaticofacial nerve (ZFN) and the infraorbital nerve (ION). The receptor areas of these nerve endings are used to test compounds applied to the cheek skin. Diagram adapted from a study by Hwang et al. [Cutaneous innervation of the lower eyelid. J. Craniofacial Surgery 19:1675-1677, 2008].

[0119] In these studies, the primary test site was the zygomatic (cheek) skin. Alternatively, if the coolant is used for vulvar pruritus, it can also be applied to the skin above the labia via a spray. The coolant can be applied directly to the site of injury and / or inflammation. Secondary sites are the skin of the frontal bones and scalp, but these sites require higher concentrations of coolant. In practice, the coolant can be sprayed or applied (e.g., with a swab or pad or in a gel, lotion, cream, or ointment) to the skin of the eye sockets, cheeks (malars), or to the skin under the eyes and between the cheeks and nose. For this site, the receptive area is from subbranches of the trigeminal nerve, namely the zygomaticofacial nerve of the maxillary nerve (V2) and the supraorbital and infraorbital branches of the frontal nerve (V1).

[0120] Methods of Administration. Administration of the DIPA compound can be achieved by dissolving the compound in a liquid carrier, such as in water or saline, or as a solution, hydrogel, lotion, swab, wipes, or as an aerosolized spray in a solid or semisolid carrier, such as a cream or ointment. Gels are semisolid, jelly-like formulations with varying degrees of viscosity. Gels form a solid three-dimensional network that spans the volume of a liquid medium. Gels are made of gelling agents that are cross-linked or associated with a liquid phase. Examples of gelling agents include: cellulose derivatives [methylcellulose, carboxymethylcellulose, hydroxypropylcellulose; carbomers [ 910, 941]; Poloxamer Carbomer polymers, as well as natural polymers such as tragacanth, gum arabic, gelatin, sodium alginate, alginic acid, and xanthan gum. Single-phase systems are gels plus active ingredients that dissolve in water [no visible particles] and are clear in appearance. Topical gels liquefy optimally upon contact with the skin or mucous membranes. Compounds of Formula 1 are suitable for delivery as gels because they are soluble in water and form single-phase systems at therapeutic concentrations. Topical gel formulation methods are described in detail on websites such as Lubrizol.com [a company that manufactures cosmetic, personal care, skin care, and eye care ingredients]. The preferred concentration of the DIPA compound is 0.01 to 2.0% weight / volume. Unless otherwise specified, weight / volume is measured in units of g / cm3 or g / mL, so that 0.01% weight / volume is obtained from 0.1 mg (0.0001 g) of DIPA compound in 1 cm3 of composition; 2% weight / volume is obtained from 20 mg (0.02 g) of DIPA compound in 1 cm3 of composition.

[0121] For liquid carriers, preferred single administration volumes are 0.02 to 0.15 mL. Such volumes, for example, delivered as a lotion or wipe, do not result in excessive liquid remaining at the administration site due to absorption of the liquid. For liquid carriers, preferred concentrations of the DIPA compound range from 0.5 to 30 mg / mL. For the orbits, preferred concentrations are 1 to 5 mg / mL. For the malar and infraorbital skin, preferred concentrations are 5 to 10 mg / mL. For the forehead skin and scalp, preferred concentrations are 10 to 30 mg / mL. Preferred amounts of the DIPA compound administered at the administration site are 0.01 to 5 mg; e.g., 0.1 to 5 mg.

[0122] Pre-medicated wipes can be used to wipe the DIPA compound from the target skin, which is well known in personal care products, for example, for wiping the skin of an infant after a diaper change, or for removing facial makeup (e.g., Pond's 6"x8" (15cm x 20cm) Clean Sweep Cleansing and Make-up Remover Towelettes). Typically, these wipes are packaged as disposable sealed units or multi-unit dispensers. For single units, suitable packaging materials are relatively steam impermeable to prevent the wipe from drying out and form a "peelable" seal. Suitable wipe materials for practicing this discovery include fabrics formed from polyamide (20% nylon)-polyester, rayon (70%)-polyester (30%), polypropylene nonwovens, polyethylene terephthalate (PET), polyester polypropylene blends, cotton, viscose, rayon or microfiber (synthetic fibers measuring less than one denier or one tex).

[0123] Alternatively, solutions containing DIPA compounds may be supplied in a reservoir bottle with a separate applicator, or as prepackaged single units. For example, the Puritan 803PCL applicator is an ideal cotton swab applicator attached to a 3-inch (about 7.5 cm) polystyrene rod for delivering DIPA compounds to the periorbital skin. Examples of such applicators that may be individually packaged include the SwabDose from Unicep (1702 Industrial Avenue, Sandpoint, Idaho, USA). TM , and Pro Swabs from Empire Manufacturing, Inc. (3828 Hawthorne Court, Waukegan, IL). Each applicator tip is saturated by dipping an absorbent material (e.g., 40 to 100 mg of cotton) at the tip into 0.1 to 1.5 mL of an aqueous solution of a DIPA compound and is packaged individually.

[0124] For facial applications, instruct the individual to gently rub or spray the cream, lotion, gel, or wipes onto the targeted facial skin, eyelid closure, or other skin surface. Application instructions may include teaching the individual to repeat applications or "top-ups" to ensure that enough of the composition is delivered to the target. Once the subject understands the intended effect, the individual may adjust the dosage as necessary (e.g., by dabbing on the medial or lateral rim of the eye socket) to achieve the desired effect. Individuals have been observed to quickly learn how to effectively apply the cooling agent after one or two attempts.

[0125] For anogenital skin or other highly sensitive surfaces, the DIPA compound can be wiped or sprayed, for example, to deliver a volume of about 0.15 ml per unit. Alternatively, a dropper can be used with a wipe of soft material (such as 100% cotton).

[0126] Mechanism of Action Sensory neurons express receptors and ion channels on their membranes to detect various stimuli. The stimuli are converted into electrical signals by the receptors, which are transmitted to the central nervous system (spinal cord or brain) and become sensations. These sensory receptors are transducers, and this process is called transduction.

[0127] DIPA compounds relieve skin discomfort by inducing a "dynamic cooling" sensation at the site of administration through topical application. This sensation is very refreshing, as if a fresh cool breeze suddenly brushed across the skin (e.g., face) or cold water was splashed on the skin. In particular, the effect of DIPA-1-7 was particularly strong. This transduction process, receptor mechanism, and the importance of dynamic cooling to the antipruritic effect are further discussed here and are referred to as the "cooling sensation."

[0128] Neurophysiology: When skin temperature decreases, for example from 25°C to 10°C, small myelinated (Aδ) and unmyelinated (C-fiber) fibers increase their afferent firing rate. These neural signals, which detect heat abstraction, are transmitted to the central nervous system and produce the conscious perception of coolness and coldness. When skin temperature increases from 35°C to 40°C, the firing rate of C-fibers increases, and these fibers transmit warmth signals [Hutchinson et al. Quantitative analysis of orofacial thermoreceptor neurons in the superficial medullary dorsal horn of the rat. J. Neurophysiol. 77, 3252-66, 1997]. The mechanisms and "wires" for cool / cold and warmth perception are separate and distinct, but may also inhibit each other in the periphery. Sensory receptors are modality-specific and do not respond to mechanical stimulation. At the molecular level, the target binding sites for coolants are thought to be located on TRP ion channel receptors that respond to temperature drops. Heat abstraction lowers the threshold for receptor firing, and the facilitated depolarization initiates an axonal response that produces a neural signal.

[0129] The central responses of these cool-sensing neurons have been recorded from the superficial medullary dorsal horn of the rat in response to innocuous thermal stimulation of the rat face and tongue [Hutchinson et al., 1997]. Step changes of -5°C stimulate cells with static firing rates and cells with dynamic properties [Davies et al. Sensory processing in thermal sensory afferent pathways. J. Neurophysiol. 53:429-434, 1985]. Similar studies in cats and humans have shown that step changes (dynamic changes) in temperature, as low as -0.5°C / second, can be readily detected by neuronal and psychophysical measurements [Davies et al. Sensitivity of the face to the rate of temperature change: neurophysiological and psychophysical evidence from cats and humans. J. Physiol. 344:161-175, 1983]. From studies of the spike patterns of neuronal firing (impulses per second), it is clear that dynamic rather than static firing responses to temperature changes are the most powerful stimulus, producing the cool / cold sensation. That is, the brain "sees" -°C / t rather than absolute °C. Therefore, a coolant of -°C / t that simulates neural firing will produce "dynamic cooling".

[0130] Dynamic cooling treats paresthesias and pruritus. Dynamic cooling (vs. static cooling / coldness) is essential for a strong sensory effect. For example, if a person feels fatigued while driving a vehicle, turning on the air conditioning and blowing air to the face will counteract the fatigue [dynamic cooling]. But simply turning on the air conditioning to lower the ambient temperature and feeling cold inside the vehicle [static cooling] will not make much of a difference. The benefits of topical sensory therapy are illustrated here with a case study.

[0131] Receptor Mechanism: There is a consensus that "TRP-" ion channel receptors (e.g., A1, M8, and V1 to 4) are the main elements of physiological temperature detection. The TRPM8 receptor is the receptor that responds to sensory / cooling agents such as menthol and icilin [McKemy et al. Identification of cold receptors reveals a general role for TRP channels in temperature sensation, Nature, 416, 52-58, 2002]. TRPM8 is a protein with 1104 amino acid residues and six transmembrane domains. Activation of this receptor by lowering the ambient temperature leads to the opening of the pore of the transmembrane loop and the entry of nonspecific cations into the cell. The signal is then transmitted to the spinal cord or brain via Aδ (and some C) fibers.

[0132] While the concept of a role for TRPM8 in sensory physiology may be valid for physical changes in temperature, the sensory effects of chemical agents such as menthol and icilin are more complex. Menthol not only stimulates TRPM8 in vitro, but also TRPV3 receptors associated with warmth and glycinergic transmission, as well as other TRP receptors [Macpherson et al. More than just coolness: the promiscuous relationship of menthol and other sensory compounds. Mol Cell Neurosci 32:335-343, 2006; Sherkheli et al., The supercoolant icilin blocks the warmth-sensing ion channel TRPV3. Scientific World Journal, 2012; Cho et al., TRPA1-like channels enhance glycinergic transmission in medullary dorsal horn neurons. J Neurochem 122:691-701, 2012]. Thus, menthol and icilin are multivalent "promiscuous" coolants whose sensory effects may not be associated with any particular receptor protein. Laboratory agents that are specific and selective for TRPM8 would be valuable for experiments.

[0133] Applicants screened a large database of coolants and surprisingly found only DIPA compounds that produced superior dynamic cooling on the skin. DIPA-1-8 and DIPA-1-9 produced strong cooling effects with extended duration of action, but it did not have the superior "wow" cooling effect of DIPA-1-6 and DIPA-1-7. Other classes of coolants, such as p-menthane carboxamides, are generally short-acting and have less dynamic cooling effects, making them unsuitable for the uses contemplated herein. Therefore, DIPA compounds are ideal selective agents for TRPM8 function compared to menthol, p-menthane carboxamides, and icilin.

[0134] Based on what is known about TRPM8 physiology, it is reasonable to assume that DIPA-1-7, DIPA-1-8, and DIPA-1-9 bind to allosteric sites on voltage-gated ion channel receptors located in nerve endings that are sensitive to physical temperature drops. This binding event promotes depolarization of neurons in response to cooling / cold signals and transmits action potentials to the central nervous system via Aδ and C fibers. If the nerve endings are located on the facial skin, signals can be recorded from the dorsal surface of the trigeminal nucleus in animals, as described in the study by Hutchison et al. The subsequent transmission and integration of the signals to the head gives rise to the perception of coolness / coldness and its geographical association with the site of stimulation.

[0135] When examining the structure-activity relationships (SAR) of DIPA compounds, it was noted that a cooling effect was observed when R1 = R2 = isopropyl and R3 = C6 to C9. A strong and long-lasting cooling effect was obtained with R3 = n-octyl (C8). A refreshing and long-lasting cooling effect was obtained with R3 = n-nonyl (C9). A special attribute of the n-nonyl analog is the lack of burning / stinging sensation even at high concentrations of 5% in water. In contrast, analogs containing the sec-butyl group were less potent. As shown in the studies described herein, the differences between di-sec-butyl and di-isopropyl compounds are also reflected in animal head shaking behavior studies, an indicator of cooling effects in rats. Furry animals shake their heads like dogs because the triggering events are cool and wet stimuli. Head shaking is inhibited by heat. The wet dog head shaking behavior test is characterized by rapid alternating contractions of the pronator and supinator muscles around the spinal axis, which can be easily observed and counted. All furry and feathered animals - when wet and cold - will shake their heads like wet dogs [Dickerson et al., Wet mammals shake their heads at a frequency adjusted to dry out. J. Royal Society, Interface 9, 3208-3218, 2012; Ortega-Jimenez, VM et al. Aerial head shaking display in wet Anna's hummingbird. J. Royal Society, Interface 9, 1093-9, 2012; Wei, Pharmacological aspects of head shaking behavior induced by TRH, AG-3-5 and morphine withdrawal, Federation Proc. 40: 1491 1496, 1981].

[0136] The "wet-dog head shake" has been studied in detail in animals. Rats can shake their heads, upper torsos, or head vigorously enough to affect the entire body and cause the animal to lose balance. DIPA-1-7 and DIPA-1-8 induce vigorous head shake. For furry and feathered creatures, the purpose or survival value of head shake is to remove water droplets trapped on or near the skin. Removal of water droplets reduces the organism's energy expenditure to remove water through evaporation. The human analogue of head shake is shivering, a state caused by a general feeling of coolness / coldness. Human subjects recovering from deep hypothermic anesthesia exhibit vigorous shivering; this condition is known as postoperative shivering. Human subjects can also perform a "wet shake" when emerging from a swimming pool with deliberate effort.

[0137] Icilin (1-[2-hydroxy]-4-[3-nitrophenyl]-1,2,3,6-tetrahydropyrimidin-2-one) can induce vigorous head shaking behavior in rats [Wei. Chemical stimulants of head shaking behavior. J. Pharmacy and Pharmacology 28:722-724, 1976]. Surprisingly, two powerful p-menthane carboxamide coolants [(R)-2-[((1R,2S,5R)-2-isopropyl-5-methyl-cyclohexane acyl)-amino]-propionic acid ethyl ester and [(1R,2S,5R)-2-isopropyl-5-methyl-cyclohexane acyl)-amino]-acetic acid isopropyl ester], which have EC50 values ​​at TRPM8 receptors similar to icilin, did not induce head shaking (in male rats injected subcutaneously at 50 mg / kg and observed for 1 hour). Icilin activation on the TRPM8 receptor was abolished by the G805A mutation in the second to third transmembrane loop, but the effect of menthol was not affected. DIPA-1-6, DIPA-1-7, and DIPA-1-8 may also have specific binding and activation sites on the TRPM8 receptor that are not shared by menthol or p-menthane carboxamides. Wei and Kuhn's study showed that DIPA-1-6 and DIPA-1-7 were still active on the TRPM8 receptor with the G805A mutation.

[0138] Watson et al., 1978 [New compounds with the cooling effect of menthol. J. Soc. Cosmet. Chem. 29: 185-200, 1978] showed that polar oxygen groups capable of hydrogen bonding are an essential structural requirement for biological activity. Hückel molecular orbital calculations of the isopropyl analogs and the sec-butyl analogs (using Molecular Modelling Prov6.0.3, ChemSW Inc, Fairfield, CA 94534, USA) showed that the oxygen in the sec-butyl entity had a slightly higher local negative charge (0.007e), indicating that the sec-butyl substituent contributes to a higher affinity of the oxygen for the receptor hydrogen binding site. Therefore, the isopropyl group may be able to bind and dissociate faster with the receptor due to its "looser" affinity, which is conducive to the receptor to produce a dynamic start and shut down reaction. This rapid interaction with the binding site will facilitate a more "dynamic" and intense cooling stimulus and lead to the so-called head shaking phenomenon.

[0139] TRPM8, TRPA1, and TRPV1 receptor assays: TRPM8 is a cation channel activated by cold temperatures and cooling compounds such as menthol and icilin. In this application, the Fluo-8 Calcium Kit and a Fluorescence Imaging Plate Reader (FLIPRTETRA TM) instrument evaluated the in vitro effect of the test compound on the cloned hTRPM8 channel (encoded by the human TRPM8 gene and expressed in CHO cells). In order to examine the specificity of the test compound, it was further tested on the TRPV1 channel (the human TRPV1 gene was expressed in HEK293 cells) and the TRPA1 channel (the human TRPA1 gene was expressed in CHO cells). These assays were performed by ChanTest, located at 14656 Neo Parkway, Cleveland, Ohio, USA. After the cells were cultured overnight, they were seeded at a density of approximately 30,000 cells / well and loaded with 2M Fura-2 (Molecular Probes, Leiden, The Netherlands) for about 1 hour and then placed on a glass cover slip. The test solution was added to a position close to the cell using a micropipette. Using excitation wavelengths of 340 and 380nm and an emission wavelength of 520nm, the emission intensity of the cell was measured, and the measurement was performed every 4 or 5 seconds for 90 seconds. The ratio of fluorescence emission intensity at 340 nm / 380 nm excitation (R, in single cells) was recorded using FlexStation and ImageMaster software suite (PTI, South Brunswick, NJ). Each sample concentration was tested in triplicate and the points were fitted using a sigmoid function by nonlinear regression to obtain an estimated EC50 (median effective concentration) (GraphPad Prism software, La Jolla, CA). The in vitro assay provides information on relative potency and selectivity for the receptors. DIPA is selective for TRPM8 and does not activate TRPV1 or TRPA1.

[0140] Choice of active ingredient. Ideally, an active pharmaceutical ingredient (API) designed for keratinized skin should be stable, nontoxic, and sufficiently long-acting and potent to activate the mechanism leading to the analgesic effect. The API should be miscible in the formulation so that a constant concentration is maintained during the manufacturing process. The final product should meet standards for purity, cleanliness, and sterility. In terms of formulation, the API can be liquid under standard temperature and pressure (STP) conditions and dissolve uniformly in neutral pH and / or isotonic solutions. Sterility of the final product can be best achieved by using purified reagents and microfiltration, heating, or irradiation. Standard excipients such as emulsifiers, isotonic saline, solvents, stabilizers, and preservatives can be added to optimize the formulation, but important ingredients should preferably be soluble in aqueous media such as purified water or standard dermatological solvents.

[0141] For a particular individual, the perceived sensation is a function of the specific coolant, dosage, carrier carrying the coolant, topical administration method, and properties of the target surface. Applicants have screened the effects of compounds such as icilin and p-menthanecarboxamides on facial skin (Wei. Sensation / coolant for skin discomfort. Journal Skin Barrier Research 14:5-12, 2012). These studies determined that DIPA compounds have the desired properties of an ideal API for paresthesia and pruritus. In summary, the design concepts for selecting a specific DIPA include: A rationale for using a "dynamic cooling" sensation to relieve skin sensory discomfort, and a description of the neurophysiological and receptor mechanisms of this action. This sensory effect is unusual and has only been found in certain DIPA compounds. Devise a method to deliver the desired compound to its receptive area, taking advantage of the water solubility of these analogs, thereby reducing the need for excipients. · Experimentation to find the ideal compound: DIPA-1-7, DIPA-1-8, and DIPA-1-9 are water-soluble (clear solutions are obtained in distilled water up to 20 mg / mL), heat-stable, and may produce a "strong cooling" sensation for up to five to seven hours at application concentrations of 1 to 10 mg / mL. Tachyphylaxis does not develop with repeated applications. DIPA-1-7 is more likely to produce a cooling sensation than DIPA-1-9. Define the receptor targets of these compounds in vitro and perform experiments to show the selectivity of the selected DIPAs. Define an animal model (e.g., “wet dog shaking head”) to illustrate the properties of “dynamic cooling” and allow for further investigation of the mechanism of action and selectivity of the various analogs. Tests in human volunteers have shown the effectiveness of DIPA compounds in reducing skin paresthesias caused by various skin diseases. Tests in human volunteers have shown that DIPA compounds, particularly DIPA-1-7, are effective in relieving skin paresthesias and therefore can be used as antinociceptive or antipruritic agents to treat skin diseases. Application Examples of DIPA Compounds

[0142] DIPA compounds, when applied to keratinized skin, have a cooling effect that mimics thermal abstraction, but does not change tissue temperature. These compounds penetrate the skin barrier, reach the nerve endings of the epidermis and dermis, and enter the systemic circulation to exert a cooling effect. These effects are obtained in small volumes (e.g., 0.1 to 0.5 ml) with application concentrations of 1 to 20 mg / ml, or 0.1 to 2% weight / volume. The onset of the effect is rapid, less than 5 minutes, and the cooling sensation is intense, refreshing and long-lasting. Compounds with similar skin bioactivity are currently unknown or unused in cosmetic or therapeutic applications. DIPA has these unusual properties, making it possible to have new applications in a variety of skin diseases. This is illustrated by the use of DIPA in various skin diseases.

[0143] Dermatitis and Itch: Topical application of DIPA produces a cooling sensation. In cases of paresthesia and pruritus, these analogs exert antipruritic and other antinociceptive effects. As shown in the case studies described herein, various formulations effectively stopped itching and discomfort. The most surprising recent discovery is the ability of DIPA to act on intact skin to stop itching. This has been shown in patients with urticaria, cholestatic pruritus, and scalp pruritus. DIPA-1-7 is also effective against miliaria rubra (stinging heat) and refractory prurigo nodularis (a chronic atopic dermatitis). There are currently no known topical medications that work quickly against these conditions. Data also show that DIPA is effective against blepharitis, conjunctivitis, and eye pain. On the anogenital surface, DIPA is effective against lichen sclerosus and vulvar pruritus. Relief of itching and paresthesia usually occurs within 5 minutes of DIPA application and lasts for several hours, a clinically significant duration.

[0144] Topical medications for the relief of paresthesia and pruritus have many uses in patients with skin disorders, with approximately 80% of patients complaining of itching and skin irritation, including: a) Relieve irritation, itching and pain caused by dermatitis (atopic dermatitis, contact dermatitis and irritant dermatitis, various eczema); b) Itching and discomfort caused by skin infections, insect bites, sunburn, photodynamic therapy of the skin (e.g., actinic keratosis, basal cell carcinoma), and lichen sclerosus; c) Itching due to dryness (especially itchy dry skin in the elderly), psoriasis, or seborrheic dermatitis; d) perianal pruritus, hemorrhoidal discomfort, anal fissure pain, pain or itching caused by anal fistula, pain after hemorrhoid surgery, perineal inflammation, anogenital skin inflammation and discomfort caused by various local causes (such as incontinence, diaper rash, tingling heat rash and perineal inflammation); e) pain caused by burns, trauma, disease, lack of oxygen or irritation of the skin (e.g., skin damaged by laser surgery, diabetic ulcers, sunburn, radiation), and procedures related to wound debridement and healing; f) Stomatitis, cheilitis, itchy lips caused by cold sores or gingivitis; g) vulvar pruritus and pain (e.g., due to candidiasis or idiopathic causes such as vestibulitis and vulvodynia), dyspareunia, anogenital infections, including warts and sexually transmitted diseases, fungal infections, viral infections (especially in immunocompromised patients); h) Pain caused by conjunctivitis, blepharitis, ocular surface irritation, trauma and corneal abrasion, and pain after ophthalmic surgery.

[0145] Of particular interest is the use of DIPA-1-7 and DIPA-1-8 for scalp itching, for example, in seborrheic dermatitis and psoriasis; these endpoints are unmet medical needs. DIPA-1-7 may also be used to refresh the skin before applying or after removing makeup from the skin, reduce the irritation of benzoic acid when treating acne, and reduce sebum secretion and the appearance of "oily" skin.

[0146] Breaking the itch-scratch cycle. Itch is a sensation that causes the urge or reflex to scratch. Itch can be very intense and trigger compulsive behavior. For example, some people scratch their ankles until they bleed because of the itch caused by insect bites (midges and sand flies). Scratching may have survival value because it can get rid of parasites and insects on the skin, but for humans, excessive scratching can exacerbate damage in skin diseases. Scratching damages the skin, and the damage triggers more itching and scratching. This phenomenon is called the "itch-scratch cycle." MacDonald et al. proposed a mechanism by which the itch-scratch cycle exacerbates tissue damage (Acta Dermato-Venereologica 97(8):1010, 2017). He pointed out that double-stranded RNA released from injured keratinocytes stimulates TOLL-3 receptors to produce more cytokines and chemokines, thereby enhancing and perpetuating inflammation.

[0147] Therefore, anti-itch molecules may not only provide symptomatic relief, but may also play a more subtle disease-modifying therapeutic role in diseases such as atopic dermatitis where itch is localized and the itch-scratch cycle is a major contributor to pathological scratching and lichenification. Irritated skin thickens from scratching, becomes chronically inflamed and brittle, and may break down from more scratching and friction. The ability to break up scratching is not limited to atopic dermatitis, but also applies to other skin diseases such as seborrheic dermatitis, acne, or acneiform eruptions. For example, acne lesions are an inflammatory disease of the sebaceous glands of the skin, and patients constantly squeeze the lesions. The mechanical damage to the skin exacerbates the underlying tissue response. If the tissue manipulation can be broken up, then the lesions have time to heal faster.

[0148] Itch prevents a good night's sleep, and patients with atopic dermatitis will also scratch vigorously during sleep. An effective medication should prevent itching within a few minutes of application and work long enough to allow the subject to fall asleep. Subjects should be instructed to apply the medication after washing, use as needed, and apply thoroughly to the itchy area before bedtime. This is especially important in children, as the urge to scratch is instinctive and automatic, but can also damage the skin.

[0149] Adjuncts: In medicine or cosmetics, an "adjunct" is an additional substance, treatment, or procedure used to increase the effectiveness or safety of the primary substance, treatment, or procedure, or to facilitate its performance. DIPA compounds relieve sensory discomfort in the skin, have antinociceptive activity, and are effective in less than 1 minute after application. They are ideal adjuncts for medicines and dermocosmetics.

[0150] Adjuncts like DIPA-1-7 may be used to increase the “apparent” potency of another primary ingredient, thereby improving patient satisfaction and compliance with dosing schedules. For example, DIPA-1-7, at concentrations of approximately 0.5 to 2%, stops itching within minutes of application. If combined with an anti-inflammatory steroid, such a formulation may be preferred over the anti-inflammatory steroid alone, which takes longer to work. Anti-inflammatory steroids, such as hydrocortisone, trifloxyflunomide, and clobetasol, are used to treat the sensory discomfort of insect bites, contact dermatitis, atopic dermatitis, and skin conditions such as psoriasis. DIPA-1-7 as an adjunct, in addition to helping stop itching, may also help reduce the dose or frequency of application of the primary ingredient while achieving an equivalent therapeutic effect. This adjunct benefit is particularly beneficial when using skin steroids, as the adverse effects of skin steroids are well known to include collagen degradation, tissue thinning, and increased susceptibility to infection. Adjuncts that reduce the dose or promote greater potency of the primary ingredient are valuable. Other major antipruritic agents are aluminum acetate and strontium chloride or strontium nitrate.

[0151] For skin diseases, the compositions of the invention may also be used as an adjunct to procedures such as phototherapy, laser therapy, cryotherapy or ultraviolet therapy. Drugs that may be used in combination or sequentially with the DIPA compounds include anti-inflammatory steroids, anti-inflammatory analgesics, antihistamines, sympathomimetic amine vasoconstrictors, local anesthetics, antibiotics, anti-acne drugs, topical retinols, drugs for treating genital warts and skin cancer, anti-wrinkle and anti-aging skin drugs, hemorrhoid treatments, drugs for treating vulvar itching, drugs for stimulating hair growth, skin moisturizers and keratolytics.

[0152] Examples of steroidal anti-inflammatory drugs include hydrocortisone, clobetasol, clobetasol propionate, halofibrate, prednisone, dexamethasone, triamcinolone acetonide, fluocinolone acetate, fluocinolone, hydrocortisone acetate, prednisone acetate, methylprednisone, dexamethasone acetate, betamethasone, betamethasone valerate, flumethasone, fluticasone, fluocinolone propionate, etc. Examples of anti-inflammatory analgesics include naproxen, monoethylpropionic acid, aspirin, indomethacin, diclofenac, ibuprofen, ketoprofen, naproxen, pranoprofen, fenoprofen, sulindac, fenclorac, clidac, flurbiprofen, fentizac, bufezilamide, meperizine, etc. Examples of antihistamines include azelastine hydrochloride, diphenhydramine hydrochloride, diphenhydramine salicylate, diphenhydramine, chlorpheniramine, promethazine, etc. Examples of sympathomimetic amine vasoconstrictors include phenylephrine hydrochloride, oxymetazoline, naphazoline, and other imidazoline receptor agonists used for nasal mucosal decongestion and ocular surface redness and vasodilation. The ingredients of skin moisturizers fall into three categories: humectants, emollients, and preservatives. Humectants, such as urea, glycerin, and alpha hydroxy acids, help draw moisture from the air and hold it in the skin. Emollients, such as lanolin, mineral oil, and petrolatum, help fill the spaces between skin cells, lubricating and smoothing the skin. Preservatives help prevent the growth of bacteria in moisturizers. Other ingredients that moisturizers may contain include vitamins, minerals, plant extracts, and fragrances. An example of a drug that stimulates hair growth is bimatoprost. Study 1

[0153] Toxicity studies. Preliminary toxicological studies were performed on DIPA-1-7. It was non-mutagenic in the Ames test (strains TA 98 and TA100, with and without liver activation) (testing was performed by Apredica, Watertown, MA, USA). DIPA1 7 was dissolved in 3% ethanol / 97% 1,2-propylene glycol or vehicle alone and administered orally to male rats at a dose of 20 mg / kg for 7 days (10 per group). On day 8, the animals were euthanized with sodium pentobarbital and the major organs (body, heart, liver, lungs, kidneys, testes, brain) were removed and weighed. Cardiac tissue (ventricles and heart valves) and liver samples were stained with hematoxylin and eosin and examined for histology. There were no significant differences in body or organ weights between the two groups, and the histology of the heart and liver was normal. Study 2

[0154] Tissue temperature. The compounds of the invention can cool but not change tissue temperature. The average forehead skin temperature of the subjects (N=5) was measured after applying DIPA-1-7 (wipes with 20 mg / mL distilled water) to the forehead skin. The results are summarized in Table 5. The subjects noticed that the cooling effect of DIPA-1-7 on the skin lasted for 30-45 minutes; however, skin temperature was not affected. Study 3

[0155] Effects of Compounds on Skin. When a test compound is applied to the skin, the sensation produced can be described. The quality of the sensations produced by individual compounds favors certain unique characteristics. The sensations evoked, their descriptors, and their proposed mechanisms of action are summarized in Table 6. For any compound, there may be some overlap in activity, but generally a compound occupies only one or two categories of effect. For example, icilin is entirely cooling, with almost no "cold" sensation. DIPA-1-6 and DIPA-1-7 are exceptions in producing a pleasant, intense "dynamic coolness." DIPA18 and DIPA-1-9 are agents that produce an intense cooling sensation.

[0156] In the studies described herein, the sensation of coolness / coldness was rated as 0, 1, 2, or 3, where: 0 means no change; 1 means slight coolness or coldness; 2 means clear signs of coolness or coldness; and 3 means strong coolness or coldness. The sensation was recorded at intervals of 5 to 15 minutes until a zero value was obtained twice in a row. The onset of the drug effect was considered to be the time when 2 units of coolness intensity were reached.

[0157] The duration of the perceived effect was defined as the offset time minus the onset time. The offset time of the drug effect was defined here as the time at which the cooling intensity dropped below 2 units after having previously exceeded 2 units. Inactive compounds were defined as those that did not exceed 2 units of cooling for 5 minutes or more after application. For compounds with an action time of more than two hours, the offset endpoint was sometimes unstable because the sensation of cooling / coldness can fluctuate based on environmental variables such as sunlight, ventilation, activity, and the "reservoir effect." For example, DIPA-1-8 and 2-8 have particularly long durations of action on the skin.

[0158] The effects of the test compounds on the facial skin were determined. The compounds were tested on the zygomatic skin (malar region). The test compounds were applied using cotton gauze (0.4 g, rectangular, 50 mm x 60 mm; CS-being from Daisan Cotton Industries, Japan). The test compounds were used at a concentration of 20 mg / ml with distilled water. The onset and duration of the sensory effect were measured using a stopwatch. The degree of "dynamic cooling" was graded from 0 to +++, with intermediate steps of + and ++. The anti-fatigue effect only occurred when there was sufficient "dynamic cooling". The results are summarized in Table 7.

[0159] 3-1 and 3-2 were also tested and found to be inactive on the periorbital and zygomatic / forehead skin.

[0160] For further comparison, newly synthesized “mixed” 1-isopropyl-tert-butyl-phosphonates (3,4-6, 3,4-7, 3,4-8, and 3,4-9) were used in the malar skin ( Figure 2 ) were tested on 20% zygomatic analogs. Due to the limited number of these analogs, the test procedure was modified. To deliver the solution to the skin, 80% polyester-20% viscose rayon wipes were cut into squares (7x8 cm, 0.45 g each) and a precise volume (2.5 ml) of the test solution was added to the wipe using a dropper bottle. Delivery and scoring of effects. An average volume of 74 ± 2 microliters, containing the test ingredients, was wiped onto the neuroreceptive area of ​​the zygomatic process (zygomatic bone). As before, the cool / cold sensation was recorded at 5 and 10 minute intervals. Quartile and half-point scoring was allowed. Scoring was stopped when two zero values ​​were observed within a 10 minute interval. At least four tests were performed for each concentration with two to three volunteer test subjects per compound. Figure 3 Results are shown for testing DIPA-1-8 at three concentrations.

[0161] Figure 3 Shown is the cooling sensation induced by topical application of different concentrations of DIPA-1-8 on the skin above the zygomatic bone. The cooling activity can be measured as the area under the intensity / duration curve (AUC) or the time of half-maximal effect (T-1 / 2) using the GraphPad Prism software package. The graph shows the AUC dose-response curve of compound DIPA-1-8 when applied at 0.5, 1 and 2% (5, 10 and 20 mg / ml dissolved in distilled water).

[0162] Figure 4 Comparison of the DIPA diisopropyl analog (3,3-X) and the mixed propyl-tert-butyl analog (3,4-X) is shown. Statistically significant differences (P<0.01) were observed between 3,3-X and the asymmetric chiral 3,4-X analog. 3,4-8 and 3,4-9 formed milky / small oil droplet emulsions at 20 mg / mL.

[0163] Notably, DIPA-1-7 selectively produced the unusual sensation of “dynamic cooling” and had an anti-fatigue effect. As can be seen from the above data, among these compounds, DIPA-1-7 elicited “dynamic cooling” around the orbital area and on the zygomatic / forehead surface. Another compound with similar attributes is DIPA-1-8, but this compound is cooler / icier, although it has the desirable attribute of a longer duration of action on the zygomatic / forehead surface. The longer duration of action of DIPA-1-7 and DIPA-1-8 on the skin increases their value as anti-itch agents. As shown in the case study described below, a single application of DIPA17 was sufficient to counteract itch.

[0164] The particular value of DIPA-1-9 lies in the pleasant cooling sensation it provides and its prolonged action after periorbital application, as well as the absence of any stinging sensation. It therefore has a special therapeutic niche in alleviating allergies in transitional epithelia, particularly the eyelids and conjunctiva. The selective properties of DIPA-1-7 and DIPA-1-8 are unexpected, surprising, and have practical applications for allergies. Study 4

[0165] The agonist activity of compounds on TRPM8 was determined using the Fluo-8 Calcium Kit and a fluorescent imaging plate reader (FLIPRTETRA TM ) instrument, the in vitro effects of the first group of test compounds (Table 8) on cloned hTRPM8 channels (encoded by the human TRPM8 gene and expressed in CHO cells) were evaluated. These experiments were performed by ChanTest (14656 Neo Parkway, Cleveland, OH 44128, USA).

[0166] Test compound and positive control solutions were prepared by diluting stock solutions in HEPES-buffered saline (HBPS) solution. Test compound and control formulations were loaded into polypropylene or glass-lined 384-well plates and placed into a FLIPR instrument (Molecular Devices Corporation, Union City, CA, USA). Test compounds were evaluated at 4 or 8 concentrations with n=4 replicates per assay. The positive control reference compound was L-menthol, a known TRPM8 agonist. Test cells were Chinese hamster ovary (CHO) cells stably transfected with human TRPM8 cDNA.

[0167] About FLIPRTETRA TM For the assay, cells were seeded in 384-well black-walled, flat-bottom microplates (Type: BD Biocoat Poly-D-Lysine Multiwell Cell Culture Plates) with approximately 30,000 cells per well. Cells were incubated overnight at 37°C to achieve a nearly conjugated monolayer suitable for fluorescence assays. The assay procedure was to remove the growth medium and add 40 microliters of HBPS containing Fluo-8 for 30 minutes at 37°C. 10 microliters of test compound, vehicle, or control solution was added to each well and read for 4 minutes. Concentration-response data were analyzed by the FLIPR Control System software (MDS-AT) and fitted to the Hill equation of the following form: Where: "Base" is the response at low concentration of the test compound; "Max" is the maximum response at high concentration; "xhalf" is the EC50, the concentration of the test compound that produces half-maximal activation; "rate" is the Hill coefficient. Nonlinear least squares fitting was performed assuming a simple one-to-one binding model. 95% confidence intervals were obtained using GraphPad Prism 6 software. The results are summarized in Table 8.

[0168] Of the 12 compounds tested, all showed full potency at the TRPM8 receptor, i.e., approximately 100% stimulation of calcium influx at the higher tested concentrations, and the data fit a sigmoidal dose-response curve. Figure 4 The EC50 values ​​of the more potent compounds (DIPA-1-7, DIPA-1-8, DIPA-1-9, 2-5, 2-6, 2-7, 2-8) fell within a narrow range, and the 95% confidence intervals overlapped. The potency of DIPA-1-7, DIPA-1-8, and DIPA-1-9 was similar and significantly greater than that of DIPA-1-5 and DIPA-1-6. In contrast, structural modifications of the comparative compounds 3-1 and 3-2 resulted in significantly reduced biological activity.

[0169] To examine the specificity of the test compounds, further studies were performed on the TRPV1 channel (human TRPV1 gene expressed in HEK293 cells) and the TRPA1 channel (human TRPA1 gene expressed in CHO cells). The test cells were Chinese hamster ovary (CHO) cells or human embryonic kidney (HEK) 293 cells, transfected with human TRPV1 or TRPA1 cDNA. The positive control reference compounds were capsaicin (a known TRPV1 agonist) or mustard oil (a known TRPA1 agonist). DIPA-1-7 and DIPA-1-8 did not show any agonist or antagonist activity on the TRPA1 channel at the maximum tested concentration of 100 μM. A weak TRPV1 agonist activity was found for DIPA-1-7, but this was not dose-dependent.

[0170] In the bioactivity studies, there was no correlation between potency and TRPM8 EC50. For example, DIPA-1-5 and DIPA-1-6 were more potent at producing shaking behavior than DIPA-1-7 and DIPA1 8 [see Study 5]. There were no distinguishing features in the TRPM8 EC50 data that could predict which compounds had potent “dynamic cooling” properties in vivo.

[0171] Further tests were conducted on the "mixed" isopropyl-tert-butylphosphine hexane and heptane analogs. Data were collected by Andersson et al., King's College London, UK, using the method described in "Regulating the cold-activated channel TRPM8 by lysophospholipids and polyunsaturated fatty acids". Here, the intracellular influx of the calcium-sensitive dye Fura-2 was used to study the effects of test compounds on TRPM8 expressed in Chinese hamster ovary cells. The cells were cultured, with approximately 30,000 cells planted overnight per well and loaded with 2M Fura-2 (Molecular Probes, Leiden, The Netherlands) for about 1 hour and then placed on a glass cover slip. The test solution was added to the position close to the cell with a micropipette. Using excitation wavelengths of 340 and 380nm and an emission wavelength of 520nm, the emission intensity of the cell was measured every 4 or 5 seconds for 90 seconds. The fluorescence emission intensity ratio at 340nm / 380nm excitation (R, in a single cell) was recorded by FlexStation and ImageMaster software suite (PTI, South Brunswick, NJ). Each sample concentration was tested in triplicate and the mean values ​​were analyzed by nonlinear regression using a sigmoid function to fit the points to obtain the estimated EC50 (median effective concentration) (GraphPad Prism software, La Jolla, California).

[0172] Figure 5 The potency of three analogs for activating TRPM8 (a cooling receptor) in transfected cells is shown. The units on the ordinate (Δ ratio) measure the incorporation of the fluorescent calcium probe into transfected cells. 3,3-7 (DIPA-1-7) is approximately 10-fold and 5-fold more potent than 3,4-6 and 3,4-7, respectively. Note that even at supramaximal concentrations, the 3,4-6 and 3,4-7 species do not reach maximal potency for activating the receptor.

[0173] Figure 5 Figure 2. Fluorescence response (Δ ratio 340 / 380) in TRPM8-transfected cells as a function of the logarithm of the test compound concentration (expressed in μM) for DIPA-1-7 (black circles), 3,4-7 (open squares), or 3,4-6 (open triangles). These experiments were performed by Andersson et al., King's College London, UK, using the methods described in his paper "Modulation of the cold-activated channel TRPM8 by lysophospholipids and polyunsaturated fatty acids".

[0174] From these results, EC50 values ​​provide no information about the quality of the thermal abstraction sensation, the duration of action, or the accessibility of the molecule to tissue targets. Identification of selective agents will require bioassays that more directly address these issues. Study 5

[0175] Activity in laboratory rats: Perioral and topical delivery - Fur and feathered animals - shake like a wet dog when exposed to cold and wet (see, e.g., Dickerson et al., 2012; Ortega-Jimenez et al., 2012; Wei, 1981). These shakes are rapid alternating contractions of the supinator and pronator muscles around the axis of the spine and can be easily observed and counted. The "wet dog shake" has been studied in detail in animals, and the behavior has been interpreted as having survival value because by removing water from the skin, the evaporative energy required to remove wetness is reduced. The triggering sensation of the shake is that water is trapped between the hair follicles or feathers. Humans have very little hair on their skin and do not usually shake, but this wet shake can be mimicked by some people emerging from a cold swimming pool. A possible equivalent behavior to the human shake is shivering, a condition caused by a generalized sensation of coolness / cold and wetness.

[0176] Drug-induced shaking in animals has been reviewed (see, e.g., Wei, 1981). Under appropriate conditions, drug-induced shaking can be observed in pentobarbital-anesthetized rats, is enhanced by hypothermia and cold, and can be inhibited by increasing body temperature. Here, test compounds were evaluated in the "wet dog shake" as a model of dynamic cooling. Using standardized procedures, the ability of test compounds to stimulate shaking responses by perioral administration and topical delivery to the abdominal skin was compared.

[0177] Perioral. Test compounds were dissolved in saline and administered by oral gavage to pentobarbital-anesthetized male albino rats at a dose of 20 mg / kg in a volume of 0.1 mL / 100 g body weight [N=3 to 4 rats per compound]. Rocking was counted during 40 minutes and recorded at 10 minute intervals.

[0178] Three of the four "diisopropyl" compounds induced vigorous shaking. The "di-tert-butyl" compounds were relatively inactive, with the exception of 2-5 which induced an average of 4 shakings during the 40-minute observation period. In contrast, DIPA-1-5, DIPA-1-6, and DIPA-1-7 produced an average of 86, 56, and 36 shakings, respectively. The strong activity of DIPA-1-5 is unusual. DIPA-1-5 has a refreshing "dynamic coolness" when applied to the skin, but its duration of action is approximately 30 minutes, significantly less than that of DIPA-1-6 and DIPA-1-7. The shorter duration of action of DIPA-1-5 limits its practical application. Perhaps its smaller molecular size aids absorption and allows greater systemic receptor contact, thus more shaking. The relationship between the shaking response and temperature sensation was further investigated [in pentobarbital-anesthetized rats. After the anesthetic is injected, the rectal temperature drops and reaches approximately 35°C in about 10 minutes. This hypothermia can be reversed by placing the animal on a heated surface and maintaining the body temperature at 38°C. DIPA-1-7 20 mg / kg peroral induced 36 ± 5 shakings in anesthetized rats (N = 6), but in heated animals, the shaking frequency was significantly reduced to 5 ± 2 shakings (N = 6) [P < 0.001]. The 2 / 3 reduction in shaking frequency under heating suggests that the shaking response is related to cold sensation and shivering.

[0179] Topical. Shaking is an excellent indicator of in vivo effects. Methods were developed to determine whether shaking occurs after topical application of DIPA compounds. The abdominal skin of pentobarbital-anesthetized rats was shaved and 20 μL of pure DIPA was applied using a micropipette to the center of a circle of approximately 1 cm in diameter on the skin, closed with a circle of cream [baby cream "Nevskaya kosmetikaDetskyi" Nevskaya Kosmetika Inc., Saint-Petrsburg 192029], as Figure 6 Count the number of shakes within 1 hour after application.

[0180] Figure 6 The method for measuring the transdermal activity of DIPA compounds is shown by applying 20 μL via a micropipette to the abdominal skin of anesthetized rats in the center of a circle enclosed by the cream. The shaking frequency was calculated within 1 hour after topical application. The data and results of local and perioral reactions are summarized in Table 9. The data are further described in Figure 6 , are graphically plotted in to show the lack of correlation between TRPM8 potency and in vivo biological activity.

[0181] Table 9 and Figure 6The data presented provide strong evidence for the novelty and special properties of these discovered compounds. Clearly, these compounds are able to penetrate biological membranes and rapidly elicit responses; events not seen with the comparative di-tert-butyl analogs. Furthermore, there was no correlation between the biological activity and the potency measure [EC50] at the TRPM8 receptor. This is the first time such a large-scale shaking response has been shown after topical [skin] application of a chemical.

[0182] Surprisingly, the inventive specific examples DIPA-1-5, DIPA-1-6 and DIPA-1-7 induced vigorous shaking. DIPA-1-8 induced only a weak reaction, while the comparative di-tert-butyl analogs 2-5, 2-6 and 2-7 were inactive. The shaking induced by DIPA-1-7 was dose-dependent. Topical application of 5 μl, 10 μl, 20 μl or 50 μl of DIPA-1-7 induced an average of 25 ± 3, 53 ± 6, 79 ± 8 and 118 ± 12 shakings, respectively, within 1 hour. If DIPA-1-7 was diluted with an equal amount of water or saline (at a 10 μl dose), shaking was visible, but if 50% (R)-1,2-propylene glycol was added as a diluent to DIPA-1-7 (at a 10 μl dose), shaking was completely suppressed. This surprising result shows that DIPA-1-7 penetrates the skin in aqueous form and is delayed by alcoholic solvents. This easy penetration of DIPA-1-7 is reminiscent of menthol and suggests that DIPA-1-7 can be easily delivered to the dermis via topical application. In addition, DIPA-1-7 could potentially be used to penetrate thick keratinized skin lesions, such as in psoriasis or hand contact dermatitis, to relieve itching and pain. Adjusting the concentration of DIPA-1-7 in a polyol solvent such as 1,2-propylene glycol can be used to control the extent of DIPA-1-7 absorption, a technique well known to formulation experts.

[0183] The surprising potency of DIPA-1-5 and DIPA-1-6 was unexpected. These molecules have a shorter duration of action on skin cooling than DIPA1-7. It is possible that these smaller molecules penetrate the skin barrier more quickly and enter the systemic circulation. However, the value of this rapid action is uncertain. In most considered topical applications, one would prefer that the drug action remain local rather than systemic. When the relative activity of the analogs in producing shakes was compared to the EC50 for TRPM8 activation, it was seen that the two variables were not correlated. The limitations of the TRPM8 EC50 in predicting biological activity have been discussed previously.

[0184] These results provide the strongest objective laboratory evidence yet that the DIPA compound of formula 1 selectively produces strong "dynamic coolness". There was no correlation between total carbon number or the number of carbons in the largest alkyl group and the magnitude of biological activity. The key factor in penetration is avoiding masking of the phosphorus oxide group. Study 6

[0185] Water Solubility and Penetration to Target Receptors The receptors on target nerve endings are embedded in layers of epithelial cells. The epidermis is only about 1 millimeter thick, but the stratum corneum, with its layers of dead cells and denatured proteins, prevents agonist molecules from reaching the nerve endings. The heels have the thickest barrier, with 86 cell layers, followed by the palms and then the backs of the hands. If you put an ice cube on your heel, you'll feel a little cold; but when you put it on the soles, where there are fewer cell layers, you'll jump. Unless the skin structure on these surfaces is damaged, such as by inflammation, applying a coolant is ineffective because the molecules can't reach the nerve endings. For the other surfaces, the genital skin (the glans penis and labia) and eyelids are the thinnest, with four to eight cell layers. The limbs, arms and legs, and the trunk (trunk) have thicker surfaces. The scalp is somewhere in between. The face is different: the cheeks are relatively insensitive, but the cheekbones and the area around the nasolabial folds are thin and sensitive. These differences are important for drug action. For itching in the bends of the limbs, such as elbows and knees, you need good drug penetration. For the eyelids and genital skin, you have to choose your molecules carefully to get the ideal effect of gentle cooling without excessive irritation.

[0186] Compared to the compounds tested in the '496 patent, applicant's preferred embodiments DIPA-1-7, DIPA-1-8, and DIPA-1-9, in which both alkyl groups (e.g., R2 and R3) are isopropyl, have high water solubility and skin penetration. Increasing water solubility to increase biological activity is counterintuitive in standard drug design. Typically, formulation experts will try to disrupt the stratum corneum using enhancers, and chemists will try to increase the lipid solubility of the molecule (e.g., M. Prausnitz et al. Skin Barrier and Transdermal Drug Delivery. Med Therapeutics 2012 Chapter 124). However, the strategy used here has been successful in the clinic.

[0187] For an equal number of total carbons, and therefore an equal molecular weight, Applicants have found that DIPA is at least 2 to 3 times more water soluble than DAPA. In the DIPA series, the polar phosphorus oxides are not masked by additional branched chain carbons. DIPA is more hydrophilic than DAPA. In vitro skin permeation studies on hairless mouse skin confirm the unusual penetrating power of the DIPA structure. In live laboratory animals, the pharmacology of DIPA and DAPA homologues differ significantly. Both DIPA and DAPA are effective by intravenous injection, but only DIPA is effective by topical or oral routes of administration, indicating that the DIPA structure is able to penetrate the skin and gastrointestinal membranes, while the DAPA structure cannot.

[0188] To further investigate the skin permeability of DIPA compounds, the flux of DIPA-1-7 and DIPA-1-9 through hairless mouse skin was tested in vitro ( Figure 7 ). Standard enhancers with polyols, such as a propylene glycol-oleyl alcohol mixture (50:50) or Lauroglycol 90, designed to increase penetration, added to the 1-7 gel reduced the permeation rate by about 50%, indicating the importance of water solubility for permeation. In studies conducted on the abdominal skin of anesthetized rats, a 50:50 propylene glycol-DIPA-1-7 mixture was found to be ineffective when tested on the animal skin, as measured by the shake endpoint, while pure DIPA-1-7 was very active. Thus, normal solvents or enhancers of skin molecules hinder rather than facilitate the delivery of DIPA across the skin barrier.

[0189] Figure 7 The flux of DIPA-1-7 and DIPA-1-9 through hairless mouse skin in vitro is shown. The test chemicals were dissolved in the gel, placed in an incubator for 8 hours, and the amount of permeation of the chemicals was measured by high pressure liquid chromatography equipped with a refractive index detector. These tests were performed by Prof Choi of Chonnam National University in South Korea. The flux of DIPA-1-7 was about 5 times that of DIPA-1-9. Standard enhancers with polyols, such as a propylene glycol-oleyl alcohol mixture (50:50) or Lauroglycol 90, which are designed to increase permeability, added to the DIPA-1-7 gel reduced the permeation rate by about 50%, indicating the importance of water solubility on permeation.

[0190] The movement of the DIPA molecule through the skin barrier in an aqueous environment is unusual and surprising. Apparently, if the polar "head" is masked by one or more carbon (e.g., methyl) groups, water solubility and permeability would be reduced. Alternatively, the symmetrical (achiral) arms (isopropyl groups) might enable DIPA to swim efficiently through the pores of the stratum corneum into the extracellular fluid of the epidermal cells until it reaches the TRPM8 receptors in the basal layer. The configuration of DIPA can be viewed as a "sperm"-like head (oxygen cloud around the phosphorus atom) allowing polar interactions with water. If the branch arms were asymmetrical (chiral), the "swimming" movement might be hindered. Study 7

[0191] Effects on the parietal sites. DIPA-1-7, the most effective dynamic cooling compound, was tested topically on the parietal sites. Using cotton wipes, a 20 mg / mL solution was applied to the skin above the buccal mucosa, in the parotid-masseteric region, in the temporal as well as periauricular regions and posterior to the mandible, using the corresponding cranial measurement points (pterion, coronal point, condylar point and mandibular angle, respectively) as landmarks. In these sites, almost no cooling effect was observed, except for the buccal mucosa. Slight cooling was observed on the buccal mucosa for approximately 30 minutes, but this was probably due to diffusion of the solution into the receiving areas of the infraorbital nerve. However, it should be noted that the sensory effect of topical application of DIPA-1-7 may be affected by inflammatory lesions that can alter permeability, for example, seborrheic dermatitis or psoriasis. Under these conditions, DIPA-1-7 is very effective for pruritus.

[0192] The head is considered an area that can help relieve thermal discomfort. In the study described by Nakamura et al.

[2012] , 11 male subjects were exposed to mild heat. The subjects wore only shorts and entered a climate chamber maintained at 32.5 ± 0.5 °C with a relative humidity of 50%. Approximately 1.5 hours later, a local cooling protocol was initiated with water-perfused stimulators placed on the head, chest, abdomen, or thighs. The subjects felt that cooling of the face and thighs was more effective in reducing thermal discomfort than cooling of the chest and abdomen.

[0193] In the study described by Essick et al.

[2004] , thresholds for detecting cooling and cold pain were determined for 34 young adults at various sites on the face, forearms, and scalp. The most sensitive site was the vermillion of the lips, where a temperature change of approximately 0.5°C could be detected, followed by the perioral area (hairy portions of the upper and lower lips, corners of the mouth), and the lateral chin. The midcheek and peri-auricular skin were less sensitive (detecting a temperature change of approximately 2°C), and the forearms and scalp were least sensitive (detecting a temperature change of approximately 3°C). The sensitivity of the orbital, zygomatic, and forehead skin was not tested.

[0194] The case studies described below demonstrate the use of DIPA in skin conditions; (a) Contact dermatitis and atopic dermatitis: for combating itchy and painful skin in subjects experiencing these skin conditions (b) Dry skin in the elderly: to break the “itch-scratch” cycle (c) Urticaria: to relieve symptoms (d) Relieve symptoms of cholestatic pruritus in patients with liver disease, (e) Scalp pruritus f) Cholestatic pruritus, g) Ocular pruritus: to relieve discomfort of eyelid inflammation (h) Lichen sclerosus: to treat discomfort of genital inflammation. The efficacy of DIPA analogs was also compared. For these conditions, including urticaria and cholestatic pruritus, surprisingly, even if the keratinized skin is “intact”, that is, the stratum corneum is normal, one would not expect the topical drug to penetrate and be effective.

[0195] In these studies, subjects were given DIPA-1-7, a 1.5% weight / volume commercial gel (IntrinsicB, Dong Wha Pharmaceuticals, Seoul, South Korea) or individual dosage units containing 1.5 to 1.75 mL of DIPA1 7, stored in 2.0 mL microcentrifuge tubes (Nova Biostorage Plus, Canonsburg, PA15317) and cotton gauze (0.4 g, rectangular, 50 mm x 60 mm; from CS-being, Daisan Cotton, Japan). For wipes, DIPA1 7 was provided as a solution in distilled water at DIPA1 7 concentrations of 5 mg / mL to 20 mg / mL. Subjects were instructed how to wet the gauze and how to wipe it on the skin. With these application methods, each wipe unit delivers approximately 0.15 mL to 0.35 mL. Subjects were instructed to rinse with water if any surface became irritated; however, no irritation or discomfort was observed with DIPA1 7, DIPA1 8, or DIPA-1-9 at the concentrations tested. Case Study 1

[0196] Contact dermatitis. Two scientists working in a laboratory developed allergic dermatitis on their hands due to contact with detergents and soaps. The hands became inflamed and extremely itchy. The itching stopped immediately with the application of a cotton swab or gauze, an effect that lasted at least 2 hours and could be renewed with repeated applications. One of the scientists, a world-renowned dermatologist who has published many articles on itching, noted that DIPA-1-7 produced an "icy" sensation on the inflamed skin and that he had never encountered such an effective compound that stopped itching so quickly.

[0197] A pharmacologist enjoyed working in the garden, but the thorns of bougainvillea and rose bushes, as well as the hairs of rhododendron leaves, irritated his skin and caused intense itching. He noted that DIPA-1-6 or DIPA-1-7 immediately stopped the sensory discomfort on the skin, either as a 20 mg / mL aqueous solution or as a cream (mixed with Eucerin moisturizer). These effects could also be obtained with DIPA-1-8. He also noted that the irritation and itching caused by insect bites could be immediately stopped by these drugs. Case Study 2

[0198] Atopic Dermatitis. An 8-year-old boy had atopic dermatitis since childhood, with standard scars on the bends of his elbows and knees. He had been treated with topical steroids, but the skin became thin and cracked easily. He was opposed to topical ointments because they felt too "greasy" and sticky, and he felt they were ineffective in stopping the itching. He also used moisturizers. The itching interfered with his sleep, especially during flare-ups of his allergic rhinitis. His parents were concerned about his nighttime scratching, poor school performance, and lack of concentration. The subject was given 8 x 8 cm wipes soaked with 2 mL of DIPA-1-7 in a 10 mg / mL aqueous solution and was instructed to use the wipes in the evening after washing and wiping the itchy skin areas in preparation for bed. The wipes were immediately effective in reducing itching and scratching, and promoting sleep. After 2 weeks of use, the skin lesions became less red, formed crusts, and gradually healed. It was clear that the itch-scratch cycle had been alleviated. The boy became happier, and he focused more on schoolwork. His parents were very satisfied. Case Study 3

[0199] Itch and dryness in the elderly. An 86-year-old retired widower decided to move from California to a hotel suite in Hong Kong, China, to live permanently. He had been an avid and skilled golfer for many years and suffered from actinic keratoses and dry skin. Over time, his skin became itchy, especially on his forearms and back. At first, scratching his back with a stick helped, but the skin became damaged, infected, and inflamed. He used Eucerin's "Atopic Control," which helped relieve the dryness, but found it expensive, heavy, and "greasy," although it did provide some protection and relief. During the hot summer months in Hong Kong, China, when the air conditioning was on full blast, and the dry fall, his skin itching and inflammation became unbearable. His dermatologist prescribed a strong topical steroid, but his skin became brittle, infected, and ulcerated in certain areas. His life became miserable because of his skin complaints. He agreed to try DIPA-1-8 solution, 10 mg / mL in isotonic saline. He applied approximately 20 drops of DIPA-1-8 to an 8 x 8 cm, 100% viscose, 50 g / m2 wipe. The volume transferred to his skin after wiping was approximately 0.2 to 0.25 ml, so the total dose per wipe was 2 to 2.5 mg. The topical application of DIPA-1-8 relieved his itching within 3 to 5 minutes of wiping, and he no longer complained of skin discomfort. His live-in nurse commented that he no longer scratched as frequently. He said that the wipes also gave a moist feeling when applied to the face, so they might be suitable for cosmetic applications. He continued to use the wipes as needed, and his skin formed a crust, healed, and returned to its normal appearance. His only negative comment was that the solution made him feel too cool when the air conditioner was on a high setting. He continued to use the wipes until his death three years later from a bulbar stroke. Case Study 4

[0200] Urticaria. Urticaria (wheals) is an allergic disease in humans that manifests as a rash (raised bumps) on the skin. The redness and itching symptoms on the skin are mainly caused by the release of histamine into the dermis by mast cells. Seafood ingestion is a common trigger for urticaria. The following is a case description of urticaria treated with DIPA-1-7, formulated in a gel manufactured by Dong Wha Pharmaceuticals in Seoul, South Korea at a concentration of 1.5% weight / volume. A female patient with a history of urticaria went on a seaside vacation in the south of France and consumed seafood pasta, ground crab meat, and mixed seafood soup over a two-day period. She developed widespread swelling on her buttocks with typical signs of inflammation, namely "calor" (a feeling of heat when inflamed tissue is touched), "rubor" (redness caused by dilated blood vessels), "tumor" (swelling), and "dolor" (pain and itching). Wheals also appeared on the skin above the collarbone and on the neck. This was painful. The gel was applied to the skin and began to reduce all four signs of inflammation in about 5 to 10 minutes. The subject described the effect as "burning cold" followed by an intense coolness, but very suitable for reducing the itching sensation and the "hot" sensation of the red bumps. The swelling, redness and "flare-ups" were significantly reduced 30 minutes after application. The gel was applied again 3.5 hours later, and the subject was then given three tablets of fexofenadine (120 mg) and one tablet of chlorpheniramine (4 mg). The subject considered all signs and symptoms of urticaria to be at least 50% reduced and "under control" within 12 hours, and the rash disappeared after three days without recurrence.

[0201] This is the first report in which skin paresthesias (itching and heat sensations) and other signs of inflammation caused by urticaria were rapidly reduced after the application of a topical medication (1.5% DIPA-1-7 in gel). The rapid and effective application of DIPA-1-7 to relatively thick skin buttocks (15 to 18 cell layers of the stratum corneum) suggests penetration into nerve endings, thereby reducing symptoms and signs of inflammation. The intensity of the therapeutic effect and rapid onset of action were sufficient to benefit patients. An additional case study of 8 patients with urticaria skin disease using DIPA-1-7 gel was obtained by a well-known dermatologist at a major hospital in Seoul, South Korea. Satisfactory itch suppression was achieved in 75% of the patients. Five cases of atopic dermatitis, six cases of seborrheic dermatitis, three cases of pruritus nodularis, and three cases of herpes zoster were also included in the study. In the cases tested, the intensity of skin paresthesias was evaluated on a visual analog scale after one week of DIPA-1-7 application. Clearly, DIPA-1-7 gel is beneficial for a variety of skin diseases. These results have now been published in Jung MJ, Kim JC, Wei ET, Selescu T, Chung BY, Park CW, et al. A randomized, vehicle-controlled clinical trial of a synthetic TRPM8 agonist (Cryosim-1) gel for the treatment of pruritus. Am J Dermatol 84(3):869-71. Case Study 5

[0202] Scalp itch. The scalp is a common site of itch. Topical treatments are practical, but targets and pathological lesions are often difficult to visualize. Factors such as hair, sebum, and scalp thickness also affect drug penetration to the target. Therefore, effective treatment of scalp itch is an unmet medical need. A common trigger for scalp itch is the use of hair dyes. Scalp scratching may also increase under psychological stress, but scratching is considered unhygienic and subject to social stigma. We conducted a study on scalp itch in human subjects and published the results [Kang SY, Choi MG, Wei ET, Selescu T, Lee SY, Kim JC, et al. TRPM8 agonist (cryosim1) gel for scalp itch: a randomized, vehicle-controlled clinical trial. Eur J Dermatol Venereol. 2022;1-2]. Patients with scalp itch were treated with DIPA-1-7, which was formulated in a gel at a concentration of 1.5% weight / volume manufactured by Donghwa Pharmaceuticals, Seoul, South Korea. A total of 25 to 31 subjects with scalp pruritus were enrolled. In the subjects tested, there was a clear and significant relief of scalp pruritus. This is the first double-blind report in which a topical cooling agent has been used to treat scalp pruritus. The intensity of the therapeutic effect and the rapid onset of action were sufficient to benefit the patients. In these patients, there was intense itching but no visible lesions on the scalp. Case Study 6

[0203] Cholestatic Pruritus. An 80-year-old, prominent history professor was diagnosed with advanced liver cirrhosis and developed severe, widespread pruritus. His children learned about the DIPA anti-itch medication and requested a sample because the subject was constantly itching and scratching. The subject's skin was intact and had no rash. The condition was diagnosed as cholestatic pruritus. The subject was given cotton gauze squares and a 30-mL plastic dropper bottle containing 2% DIPA-1-7 in water. He was instructed to wet the square as needed and rub the solution on the itchy areas. The subject stated after the first try that it was the best itch medication he had ever tried and that it was effective. He used one 30-mL bottle approximately every three days and requested more. This regimen continued until the subject died three months later. Case Study 7

[0204] Ocular pruritus of various etiologies. A 28-year-old female subject visited her optometrist for symptoms of dry eye, including ocular surface discomfort, blurred vision, burning sensation, sensitivity to light, and problems reading, driving, and using smartphone screens. Examination revealed that she had eyelid margin congestion, Meibomian gland obstruction, some eyelid margin thickening indicating epithelial hyperkeratosis, and cosmetic residue in the eye. Further questioning revealed that she was using a bimatoprost solution to induce hair growth but was applying the solution two to three times daily (rather than the recommended daily) because she was dissatisfied with the slow rate of eyelash growth.

[0205] She was diagnosed with blepharitis and conjunctivitis and was instructed not to use eye makeup and given Blephaclean TM ocular wipes, which are single-piece wipes with a cleansing solution to clear the Meibomian gland ducts and maintain ocular hygiene. However, the subject strongly objected to the irritation caused by the cleansing wipes and her inability to continue using the rather expensive bimatoprost solution. The subject was recruited to participate in a clinical trial of DIPA-1-9 wipes, 2 mg / mL in water, and was instructed to use them once daily in the morning, once in the evening, and two more wipes as needed throughout the day. She felt much better immediately after using the DIPA-1-9 wipes and commented that she now had a cool and refreshed feeling on her ocular surface and margins. She stated that her bimatoprost solution was no longer irritating now and that her eyelashes were now thick and luxurious. The blepharitis and conjunctivitis had disappeared. She recommended that DIPA-1-9 be added to the bimatoprost solution as an adjunct. She was willing to pay for a continued supply of DIPA-1-9 wipes.

[0206] Recent research on the treatment of ocular diseases in human subjects has been published (Yoon HJ, Kim J, Yang JM, Wei ET, Kim SJ, Yoon KC. Topical TRPM8 agonists relieve neuropathic ocular pain in patients with dry eye: a pilot study. J Clin Med. 2021;10(2):250). Case Study 8

[0207] Lichen sclerosus. A 40-year-old patient presented with penile lichen sclerosus. This is an inflammatory skin disease of the glans penis and foreskin that, in this particular case, is associated with intense pruritus and paresthesia (burning sensation). Under the supervision and care of a dermatologist, the patient volunteered to try the use of DIPA-1-8 on his lesions. He was provided with various concentrations of DIPA-1-8 dissolved in distilled water. After self-experimentation, he concluded that concentrations of 1 to 1.5 mg / mL of DIPA-1-8 produced significant relief, but that 2 mg / mL of DIPA1 8 was too cold and uncomfortable. The solution was applied using a cotton swab or gauze wipe. The advantage of using a DIPA formulation for treating genital skin is that it is water soluble. This minimizes the need for excipients and the potential for further irritation. The subject suggested that an aerosol spray may also be a convenient method of drug delivery.

[0208] Commercial samples of 1.5% DIPA-1-7 gel, called Intrinsic B, are available from South Korea, allowing for further evaluation in several female patients with lichen sclerosus. These patients noted an initial strong stinging sensation when the gel was applied to crusted wounds caused by scratching, but they said the gel helped suppress scratching behaviors caused by paroxysmal itching in social situations. Another group that could benefit from DIPA wipes is postmenopausal women with a history of breast cancer. This group cannot use hormone replacement therapy (HRT) and, with aging, experience atrophy of the vulvar epithelium and decreased vaginal discharge. These conditions cause itching that can be relieved by using 1% DIPA-1-8 wipes.

[0209] These studies demonstrate the anti-nociceptive properties of DIPA-1-7 and DIPA-1-8, particularly in the context of genital itch. DIPA1 8 has a longer duration of action than DIPA-1-7 and may be the agent of choice for dermatological applications. Further studies have shown that the application of 2 mg / mL of DIPA-1-9 to the glans penis or vulva using wet wipes produces a mild cooling and refreshing sensation, offsetting any inflammatory discomfort. Case Study 9

[0210] Three subjects decided to systematically compare the sensory effects of DIPA-1-6, DIPA-1-7, DIPA-1-8 and DIPA-1-9 on the ocular surface. Each compound was prepared in distilled water at a concentration of 1 mg / ml. A cotton swab of a specific size (Puritan 803-PCL) was used, with a 55 to 75 mg cotton ball wrapped around the tip of a three-inch polystyrene rod, and immersed in the solution. Then, with the subject's eyes closed, the tip was applied to the lower part of the upper eyelid, on the eyelashes, and two wiping movements from the outside to the inside were performed. The subject was then instructed to blink. By blinking, the solution was evenly distributed on the anterior corneal membrane. This "rubbing" administration method released a total of about 35 microliters of liquid onto the surface of both eyes. DIPA 1 6 caused significant stinging and discomfort, so it was not studied further. DIPA-1-7 and DIPA-1-8 produced a strong and refreshing cooling sensation, offset ocular irritation, and enhanced cognitive function. For example, the subjects felt that they were able to focus on distant objects and enjoy the field of vision. They felt alert and refreshed. However, both DIPA-1-7 and DIPA-1-8 left a small residue on the eyelids; subsequent washing with a washcloth may cause eye irritation. Surprisingly, DIPA-1-9 did not cause any eye irritation when wiping the eyelids and did not leave a residue. It also produced a refreshing cooling sensation, but not as intense as DIPA-1-7 or DIPA-1-8. On the other hand, DIPA-1-9 has desirable properties for treating ocular discomfort, e.g., discomfort caused by eye fatigue, eye surgery, airborne irritants or pollutants interacting with the ocular surface, prolonged contact lens wear, excessive sun exposure, conjunctivitis, conjunctivitis in patients with atopic dermatitis treated with dupilumab, or dry eye syndrome. Some of these results have been published in Yang JM, Li F, Liu Q, Rüedi M, Wei ET, Lentsman M, et al. A novel TRPM8 agonist relieves dry eye discomfort. BMC Ophthalmology. 2017;17(1). These wipes, used to treat ocular discomfort and visual fatigue, are available in Korea as OcuCool. Of particular note, OcuCool has demonstrated promising results in treating conjunctivitis pruritus in patients with atopic dermatitis receiving dupilumab. Observation Summary

[0211] The structure of Rowsell and Spring '496 was described over 40 years ago, but was not used in development. Applicants discovered diisopropyl analogs that were not described in '496. These analogs were subsequently synthesized and tested. The "head" of the prototype DIPA molecule is polar (hydrophilic) and soluble in a polar environment such as water. The increased water solubility of these analogs paradoxically facilitates penetration of the stratum corneum layer of dead cells to access receptors in the skin's nerve endings. Preferred Examples 1-7 and 1-8 produce a strong cooling sensation that can modulate skin paresthesias caused by various dermatitis (e.g., atopic or urticaria) and dryness (dry skin). This occurs in dermatological conditions where the skin is intact, such as urticaria, cholestatic pruritus. On the marginal epithelium of the eyelids and genitals, DIPA-1-9 is unexpectedly active, but without the "cooling" effect of DIPA-1-7.

[0212] For an equal number of total carbons, and therefore an equal molecular weight, applicants have found that DIPA is approximately 10 times more soluble in water. In vitro skin penetration studies performed on hairless mouse skin demonstrate the penetrating ability of DIPA. In live laboratory animals, the pharmacology of DIPA differs significantly from that of mixed isopropyl / tert-butyl and di-tert-butyl homologues. Both DIPA and di-tert-butyl are effective by intravenous injection, but only DIPA is effective by oral or topical routes of administration, indicating that DIPA penetrates the skin and gastrointestinal membranes better than the di-tert-butyl structure. The DIPA structure is able to rapidly, significantly and unexpectedly relieve skin discomfort in patients with intact skin and skin diseases.

[0213] The "head" of the '496 structure is covered with more lipophilic groups and is chiral, making it less likely to penetrate to the target receptor in the basal layer of the skin to achieve the same therapeutic endpoint as the preferred embodiment. Increasing water solubility is counterintuitive in standard drug design to enhance transdermal drug penetration. Typically, formulation experts would try to disrupt the stratum corneum using enhancers and chemists would try to increase the lipid solubility of the molecule (e.g., M. Prausnitz et al. Skin Barrier and Transdermal Drug Delivery. Med Therapeutics 2012 Chapter 124). However, the strategy used here has been successful in the clinic. These observations are now supported by the publication of well-designed trials in reputable journals. Therefore, Applicants believe that the discovery of the DIPA embodiment in the treatment of skin diseases is a huge leap forward in the discovery process.

[0214] References. In order to more fully describe and disclose the invention and the technical field to which it belongs, a number of publications are cited herein. Each of these publications is incorporated into this disclosure by reference in its entirety.

Claims

1. A method of treating an eye disease in a subject in need of such treatment, comprising topically administering to the subject a liquid or semi-liquid composition comprising a therapeutically effective amount of a compound of formula 1. Formula 1 wherein R is n-heptyl, n-octyl or n-nonyl.

2. The method of claim 1, wherein the composition is administered to the ocular surface, periocular skin, or eyelid of the subject.

3. The method of claim 1 or 2, wherein the composition is applied to the eyelid of the subject.

4. The method of any one of claims 1 to 3, wherein the eye disease is blepharitis or conjunctivitis.

5. The method of claim 4, wherein the conjunctivitis is allergic conjunctivitis or non-infectious conjunctivitis.

6. The method of any one of claims 1 to 3, wherein the eye disorder is itching or pain of the eye or periocular skin.

7. The method of any one of claims 1 to 6, wherein the composition is a liquid with water or isotonic saline as solvent.

8. The method of any one of claims 1 to 7, wherein the concentration of the compound of formula 1 in the composition is 0.5-20 mg / ml.

9. The method of claim 8, wherein the concentration of the compound of formula 1 in the composition is 0.5-5 mg / ml or 1-5 mg / ml.

10. The method of any one of claims 1 to 9, wherein the compound of formula 1 is 1-diisopropyl-phosphino-heptane (DIPA-1-7), 1-diisopropyl-phosphino-octane (DIPA-1-8) or 1-diisopropyl-phosphino-nonane (DIPA-1-9).

11. The method of any one of claims 1 to 10, wherein administration is at least once a day.

12. The method of any one of claims 1 to 11, wherein administration is at least twice daily.

13. The method of any one of claims 1 to 12, wherein the administration is for at least one week.

14. The method of any one of claims 1 to 13, wherein administration is by wipes or eye drops.

15. The method of any one of claims 1 to 14, wherein the compound of formula 1 is dissolved or present in micellar form in the composition.

16. The method of any one of claims 1 to 15, wherein the liquid or semi-liquid composition penetrates the skin of the subject upon topical administration and is effective to reduce or eliminate inflammation or infection at the site where the composition is applied.

17. A method of using a compound of formula 1 to manufacture a medicament for topical administration to treat an eye disease, the medicament being applied to the eyelid or another area of ​​skin around the eye in a subject in need of such treatment. Formula 1 wherein R is n-heptyl, n-octyl or n-nonyl.

18. The use of claim 17, wherein the medicament is a liquid or semi-liquid composition.

19. The use of claim 17 or 18, wherein the medicament is topically administered to the eyelid or another skin area around the eye of the subject.

20. The use according to any one of claims 17 to 19, wherein the compound of formula 1 is DIPA-1-7, DIPA-1-8 or DIPA-1-9.

21. The use according to any one of claims 17 to 20, wherein the eye disease is dry eye symptoms, blepharitis, conjunctivitis, itching or pain of the eye or periocular skin.

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