WO2010126970A1

WO2010126970A1 - Methods for treating and preventing erectile dysfunction

Info

Publication number: WO2010126970A1
Application number: PCT/US2010/032711
Authority: WO
Inventors: Daniel Brookoff
Original assignee: Optmed, Inc.
Priority date: 2009-04-28
Filing date: 2010-04-28
Publication date: 2010-11-04

Abstract

Compositions and methods for the treatment and prevention of male erectile dysfunction are provided. Such compositions and methods provide locally effective amounts of diazepam sufficient to treat or to reduce the number of episodes and severity of male erectile dysfunction without causing cognitive or other side effects associated with previous treatments.

Description

COMPOSITIONS AND METHODS FOR TREATING AND PREVENTING

ERECTILE DYSFUNCTION CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and benefit from U.S. Provisional

Application No. 61/173,410 filed on April 28, 2009, the contents of which are incorporated herein by reference in its entirety

FIELD OF THE INVENTION

[0002] The present invention relates to the field of urology. In particular, the invention provides compositions and methods for treating or preventing male erectile dysfunction and conditions associated therewith.

BACKGROUND OF THE INVENTION

[0003] Erectile dysfunction ("ED"), the subjective complaint of an inability to achieve and/or maintain an erection satisfactory for the completion of sexual activity, is a highly prevalent condition in men aged 40 to 70 years. The risk of ED increases with age and as the population continues to grow and age and it is estimated that there will be approximately 332 million men worldwide with ED by the year 2025. [0004] Normal erectile function is a hemodynamic process of blood inflow and pressure maintenance in the cavernous spaces of the penis. Following sexual arousal and the release of nitric oxide to the erectile tissue, three processes occur to achieve an erection. These are: (a) relaxation of the trabecular smooth muscle; (b) arterial dilation; and (c) venous compression. During stage (c) of the process, arterial flow fills sinusoidal spaces, compressing subtunical venules thereby reducing venous outflow. Blood flows into the cavernous spaces of the penis, thus expanding and stretching the penis into a rigid organ. The flow of blood in and out of the cavernous spaces is controlled by cavernous smooth muscle cells embedded in the trabeculae of the cavernous spaces. With normal erectile function, a

RECTIFIED (RULE 91) - ISA/US high intracavernous pressure is maintained with a low inflow rate. Sinusoidal smooth muscle atrophy and collagen deposition is a common finding in men with long standing ED of various etiologies, such as hormonal, neurological or vascular causes. [0005] Medical intervention for treatment of ED is becoming increasingly common.

Surgical procedures, penile implants and pharmacological agents have been developed for treatment of male ED in recent years.

[0006] Surgical interventions employing penile implants and various patient- controlled mechanical devices are not uniformly successful nor are they appropriate in most situations. Serious disadvantages of treating ED with a surgical implant include infections and irreversible damage to the erectile tissues of the penis.

[0007] Pharmacological methods have been developed to treat male ED. It is now recognized that vasodilators acting on the penile arteries can be beneficial in achieving an erection. Orally administered vasodilators are currently the most widely accepted treatments for male ED. Such vasodilators include for example sildenafil, better known as Viagra^®. This compound is taken orally about one hour prior to intercourse since an instant erection is not achieved with this drug. Unfortunately, this delay may lead to inconvenience for patients seeking a more rapid response. In addition, this product may cause undesirable side effects such as headache, flushing, dyspepsia and increased sensitivity to light. Of greater concern, this drug reportedly may exacerbate pre-existing heart conditions. Furthermore, sildenafil must be taken on an empty stomach and must not be taken with alcohol. [0008] A more rapid response in producing an erection has been found for sildenafil applied sublingually or intranasally. The response is often within five minutes, and the drug may have fewer side effects than when administered orally. While sublingual or intranasal administration reduces the side effects described above, the drug nevertheless enters the circulatory system where it exerts vasodilatory effects in areas other than the penis. Thus, following the nasal or sublingual route of administration, undesirable side effects still may occur, some of which may be of medical concern, as noted above. [0009] Recognition of the problems associated with systemic administration of vasodilators has led to development of methods for local delivery of vasodilators to the tissues of the penis. For example, a semi-solid vehicle containing a vasodilator for insertion into the urethra has been formulated and shown to be effective in stimulating erection. Disadvantages of this method include the requirement for administration into the urethra, contributing to transient burning or tingling effects reported in some cases, and the possibility of urethral infection and scarring. In addition, these products may be ineffective in up to 60% of patients.

[0010] An alternative and more direct route for delivery of vasodilators is injection into the corpus cavernosum of the penis. This "intracavernosal" route has been successfully used to deliver one or more vasodilators to achieve erections, and has led to the development of a treatment regimen known as intracavernosal pharmacotherapy or ICP. However, this therapy is associated with the risk of priapism and fibrosis of the tunica albuginea, related to repetitive trauma from the injections. In addition, the patients must be instructed to alternate sides to prevent penile curvature.

[0011] In addition to their side effect profiles, all of the foregoing treatments are of limited effectiveness, especially for subjects with previous medical histories of diabetes of neurologic damage. Accordingly, there remains a great need for improved compositions and methods for treating and preventing ED and conditions associated therewith.

SUMMARY OF THE INVENTION

[0012] This invention relates to the surprising discovery that local delivery of an effective amount of a pharmaceutical composition comprising diazepam is capable of preventing and treating ED and conditions associated therewith, without the problems often associated with previous treatments.

[0013] In one embodiment, the present invention relates to a method for reducing the incidence of or for treating ED comprising administering an effective amount diazepam to a male for whom such prevention or treatment is needed or desirable.

[0014] In another embodiment, the present invention relates to a method for reducing the severity of ED comprising administering an effective amount of diazepam to a male for whom such reduction of severity is needed or desirable.

DETAILED DESCRIPTION OF THE INVENTION

[0015] As used herein, a "pharmaceutical composition" refers to any combination of two or more components. It may be in the form of, for example, sprays, ointments, pastes, creams, lotions, gels, solutions, suspensions, liquids, powders or pastes or combinations thereof. The compositions may be in either aqueous or non-aqueous form. [0016] As used herein, an "erectile dysfunction" (or impotence or ED) refers to the inability of a male mammal (e.g., a human male) to achieve and maintain penile erection for satisfactory sexual intercourse. "Erectile dysfunction" is also used herein to mean the partial, temporary or episodic absence of a penile erection.

[0017] As used herein, "reduce the incidence of erectile dysfunction" means that erectile dysfunction will be prevented in a male receiving treatment according to the invention or that the number of incidences of erectile dysfunction will be reduced. As used herein, "reduce the severity of erectile dysfunction" means that the severity of erectile dysfunction is reduced as measured by the Erectile Function ("EF") and/or Sexual Health Inventory for Men ("SHIM") tests, such that the EF and/or SHIM score increases. [0018] The term "diazepam" is used herein to refer to 7-chloro-l,3dihydro-l-methyl-

5-phenyl-2H-l,4-benzodiazepin-2-one and pharmaceutically-acceptable forms and derivatives of same.

[0019] By an "effective amount" is meant a nontoxic, but sufficient, amount of diazepam needed to prevent or to reduce the incidence or severity of ED. An effective amount of diazepam is preferably less than about 50mg. In certain embodiments an effective amount is from about lmg to about 30mg. In other embodiments an effective amount is from about 5mg to about 20mg. In certain embodiments, an effective amount is less than about

5mg.

[0020] The "effective amount" of diazepam is administered locally to the penis from about 30 minutes to about 24 hours before sexual activity.

[0021] By an "effective time" is meant the range of time prior to sexual activity during which diazepam must be administered so that it will be effective to reduce the incidence and/or severity of ED.

[0022] The present invention relates to the discovery that the topical delivery of diazepam compositions to the penis is surprisingly effective in treating or preventing ED.

Dosage forms

[0023] Dosage forms for local administration of diazepam may include, for example, sprays, ointments, pastes, creams, lotions, gels, solutions, suspensions, liquids, powders or pastes or combinations thereof. The active ingredient may be mixed under sterile conditions with a pharmaceutically-acceptable carrier including DMSO or dimethylsulfone in pluronic lecithin organogel ("PLO") and may be in an aqueous or non-aqueous form. [0024] Dosage forms may contain, in addition to diazepam, carriers or excipients, such as animal and vegetable fats, oils, waxes, paraffins, starch, tragacanth, cellulose derivatives, polyethylene glycols, propylene glycols, glycerine, silicones, bentonites, silicic acid, talc and zinc oxide, other synthetic solvents, or mixtures thereof. [0025] Ointments are semisolid preparations which are typically based on petrolatum or other petroleum derivatives. As with other carriers or vehicles, an ointment base should be inert, stable, nonirritating and nonsensitizing. Creams containing the selected active agent, are, as known in the art, viscous liquid or semisolid emulsions, either oil-in-water or water- in-oil. Cream bases are water-washable, and contain an oil phase, an emulsifϊer and an aqueous phase. The oil phase, also sometimes called the "internal" phase, is generally comprised of petrolatum and a fatty alcohol such as cetyl or stearyl alcohol; the aqueous phase usually, although not necessarily, exceeds the oil phase in volume, and generally contains a humectant. The emulsifϊer in a cream formulation is generally a nonionic, anionic, cationic or amphoteric surfactant.

[0026] Specific example of emulsifϊers and surfactants include: nonionic ethoxylated and nonethoxylated surfactants, abietic acid, almond oil polyethylene glycol, beeswax, butylglucoside caprate, C₁₈-C₃₆ acid glycol ester, C₉-C₁₅ alkyl phosphate, caprylic/capric triglyceride polyethylene glycol-4 esters, ceteareth-7, cetyl alcohol, cetyl phosphate, corn oil polyethylene glycol esters, dextrin laurate, dilaureth-7 citrate, dimyristyl phosphate, glycereth-17 cocoate, glyceryl erucate, glyceryl laurate, hydrogenated castor oil polyethylene glycol esters, isosteareth-11 carboxylic acid, lecithin, lysolecithin, nonoxynol-9, octyldodeceth-20, palm glyceride, polyethylene glycol diisostearate, polyethylene glycol stearamine, poloxamines, potassium linoleate, raffinose myristate, sodium caproyl lactylate, sodium caprylate, sodium cocoate, sodium isostearate, sodium tocopheryl phosphate, steareths, and trideceths, aluminum starch octenylsuccinate, ammonium hydroxide, amphoteric-9, beeswax, synthetic beeswax, carbomer 934, carbomer 934P, carbomer 940, ceteareth-20, ceteareth-30, cetearyl alcohol, ceteth 20, cetyl alcohol, cholesterol, cyclomethicone, diglycerides, dimethicone (e.g., dimethicone 350), disodium monooleamidosulfosuccinate, NF emulsifying wax, fatty acid pentaerythritol ester, glycerides, glyceryl monooleate, glyceryl monostearate, lanolin, lanolin alcohol, hydrogenated lanolin, magnesium stearate, mineral oil, monoglycerides, polyethylene glycol, PEG 100 stearate, polyethylene glycol 6000 distearate, polyethylene glycol 1000 monocetyl ether, polyethylene glycol monostearate, polyethylene glycol 400 monostearate, polyoxyethylene glycol fatty alcohol ethers, polyoxyl 20 cetostearyl ether, polyoxyl 40 stearate, polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80, polysorbates, PPG- 26 oleate, propylene glycol stearate, quaternium-15, simethicone, sodium laureth sulfate, sodium lauryl sulfate, sorbitan esters, sorbitan monolaurate, sorbitan monooleate, sorbitan monopalmitate, sorbitan monostearate, sorbitan palmitate, sorbitan sesquioleate, steareth-2, steareth-100, stearic acid, stearyl alcohol, triethanolamine and trolamine. Other surfactants and emulsifϊers may be used, as will be appreciated by one of ordinary skill in the art. [0027] Compositions according to the present invention also may include a wide range of other optional ingredients including, antifoaming agents; buffers, neutralizing agents and agents to adjust pH; coloring agents and decoloring agents; emollients and emulsion stabilizers; humectants; odorants; preservatives, antioxidants, and chemical stabilizers; solvents; and stiffening and suspending agents. Exemplary antifoaming agents include cyclomethicone, dimethicone (e.g., dimethicone 350) and simethicone. Exemplary buffers, neutralizing agents and agents to adjust pH include ammonium hydroxide, citric acid, diisopropanolamine, hydrochloric acid, lactic acid, monobasic sodium phosphate, sodium citrate, sodium hydroxide, sodium phosphate, triethanolamine, and trolamine. Exemplary emollients include caprylic/capric triglyerides, castor oil, ceteareth-20, ceteareth-30, cetearyl alcohol, ceteth 20, cetostearyl alcohol, cetyl alcohol, cetyl stearyl alcohol, cocoa butter, diisopropyl adipate, glycerin, gyceryl monooleate, glyceryl monostearate, glyceryl stearate, isopropyl myristate, isopropyl palmitate, lanolin, lanolin alcohol, hydrogenated lanolin, liquid paraffins, linoleic acid, mineral oil, oleic acid, white petrolatum, polyethylene glycol, polyoxyethylene glycol fatty alcohol ethers, polyoxypropylene 15-stearyl ether, propylene glycol stearate, squalane, steareth-2 or -100, stearic acid, stearyl alcohol and urea. [0028] Exemplary emulsion stabilizers and viscosity builders include carbomer 934, carbomer 934P, carbomer 940, cetearyl alcohol, cetostearyl alcohol, cetyl alcohol, cetyl stearyl alcohol, dextrin, diglycerides, disodium edetate, edetate disodium, glycerides, glyceryl monostearate, glyceryl stearate, hydroxypropyl cellulose, monoglycerides, plasticized hydrocarbon gel, polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 1450, polyethylene glycol 8000, polyethylene glycols, propylene glycol stearate and stearyl alcohol. Exemplary humectants include glycerine, propylene glycol, sorbitol and urea. Exemplary odorants include hypoallergenic perfume, menthol. Exemplary preservatives, antioxidants, and chemical stabilizers include alcohol, benzyl alcohol, butylated hydroxyanisole, butylated hydroxytoluene, butylparaben, calcium acetate, caster oil, chlorocresol, 4-chloro-m-cresol, citric acid, disodium edetate, Dowicil 200 (Dow), edetate disodium, ethoxylated alcohol, ethyl alcohol, glycerin, Glydant Plus (Lonza), 1,2,6- hexanetriol, Kathon CG (Rohm & Haas), Liquid Germall Plus (ISP Sutton Labs), Liquipar (ISP Sutton Labs), methylparaben, parabens, potassium sorbate, propyl gallate, propylene glycol, propylparaben, sodium bisulfite, sodium citrate, sodium metabisulfite, sorbic acid, tannic acid, triglycerides of saturated fatty acids, Ucarcide (Union Carbide), and zinc stearate. Exemplary solvents include alcohol, castor oil, diisopropyl adipate, ethoxylated alcohol, ethyl alcohol, fatty alcohol citrate, glycerin, 1,2,6-hexanetriol, hexylene glycol, isopropyl alcohol, isopropyl myristate, isopropyl palmitate, mineral oil, phosphoric acid, polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 1450, polyethylene glycol 8000, polyethylene glycol 1000 monocetyl ether, polyethylene glycol monostearate, polyethylene glycol 400 monostearate, polyethylene glycols, polyoxyl 20 cetostearyl ether, polyoxypropylene 15-stearyl ether, polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80, polysorbates, propylene carbonate, propylene glycol, purified water, and SD alcohol 40, triglycerides of saturated fatty acids.

[0029] Examples of thickening, stiffening and suspending agents agent that are suitable for inclusion in compositions according to the present invention may include agents commonly used in skin care preparations. More specifically, such excipients include acrylamides copolymer, agarose, amylopectin, calcium alginate, calcium carboxymethyl cellulose, carbomer, carboxymethyl chitin, cellulose gum, dextrin, gelatin, hydrogenated tallow, hydroxyethylcellulose, hydroxypropylcellulose, hydroxpropyl starch, magnesium alginate, methylcellulose, microcrystalline cellulose, pectin, various polyethylene glycol's, polyacrylic acid, polymethacrylic acid, polyvinyl alcohol, various polypropylene glycols, sodium acrylates copolymer, sodium carrageenan, xanthan gum, yeast beta-glucan, aluminum stearate, beeswax, synthetic beeswax, carbomer 934, carbomer 934P, carbomer 940, cetostearyl alcohol, cetyl alcohol, cetyl esters wax, dextrin, glyceryl monostearate, hydroxypropyl cellulose, kaolin, paraffin, petrolatum, polyethylene, propylene glycol stearate, starch, stearyl alcohol, wax, white wax, xanthan gum, and bentonite. Thickening agents other than those listed above also may be used in related embodiments of the present invention.

[0030] In one embodiment of the present invention pharmaceutical formulations include diazepam in a matrix-based gel. Such matrix-based gels may include carbomer and/or hydroxycellulose, polycarbophils, propylene glycol, glycerin and water. In another embodiment suitable formulations may be in the form of vesicle/inclusion-based creams which may include lipids and/or beta cyclodextrin in a hydrophilic cream base. [0031] Such formulations optionally may include preservatives such as sorbic acid and/or benzyl alcohol. In one embodiment sorbic acid may be used as a preservative in matrix-based gels. In other embodiment benzyl alcohol may be used as a preservative in a vesicle/inclusion-based cream. In certain embodiments other preservatives may be used in addition to or instead of sorbic acid and/or benzyl alcohol.

[0032] In certain embodiments pharmaceutical formulations also may include various organic solvents to increase the solubility of diazepam. Other FDA-approved excipients may be included as well.

[0033] In certain embodiments the formulations are adjusted to a pH level between about 3 and 6, more preferably between about 4 and 5.

[0034] Representative formulations may include diazepam at concentrations from about 1 to about 20 mg/ml. Specific concentrations within this range may be prepared. For example, in certain embodiments diazepam concentrations may be formulated to include 2, 5 or 10 mg/ml.

[0035] Each composition disclosed herein may be packaged in a container appropriate for its viscosity and intended use by the patient. For example, a cream may be stored in a non-deformable bottle, or in a squeeze container (such as a tube), or a lidded jar. Such formulations may be stored at room temperature and are preferably protected from light.

Care should be taken for storing such formulations since diazepam is incompatible with certain types of plastics.

Local Delivery

[0036] Formulations according to the present invention can be administered locally to the penis of a male prior to sexual activity thereby allowing diazepam to reach a local concentration sufficient to treat or reduce the incidence of ED without the sedative side- effects that are associated with orally or parenterally administered pharmaceuticals. This route of administration also will minimize hepatic metabolism of diazepam and the formation of long-acting metabolites such as desmethyldiazepam.

[0037] Cognitive impairment is usually not associated with plasma levels below 100 ng/ml of plasma. Following the administration of an effective amount of diazepam- containing compositions, the maximum plasma level of diazepam and of its primary active metabolite, desmethyldiazepam, preferably will not exceed 100 ng/ml of plasma, preferably will not exceed 50 ng/ml of plasma and even more preferably will not exceed 25 ng/ml of plasma. Local delivery of diazepam thus eliminates, or greatly reduces, cognitive impairment associated with traditional oral or parenteral use.

[0038] It is understood by those skilled in the art that the dosage amount may vary with the severity of ED, the age, size and condition of the patient, and like factors known in the medical art. In general, a suitable dose will be that amount of the compound which is the lowest dose effective to reduce the incidence or severity of ED without toxicity.

EXAMPLES

[0039] The examples which follow provide exemplary embodiments of the compositions and methods of the present invention. Example 1 - Representative Compositions

[0040] Representative compositions according to the present invention are shown below in Table 1. Table 1

*PLO is Pluronic lecithin organogel [0041] As shown in Table 1, such compositions may include diazepam from about

1% to about 3%, although in some circumstances amounts of diazepam may be below 1% or above 3%. PLO and/or DMSO may be used as convenient excipients. Such compositions can be administered to the penis to prevent and/or treat ED.

Example 2 - Effect of local delivery of diazepam on rabbit isolated corpus cavernosum [0042] Rabbit cavernosal strips were mounted in 5 ml organ baths containing Krebs-

Henseleit solution. Propranolol, desipramine, deoxycorticosterone and normetanephrine were added to the bath in order to block β-adrenoceptors, neuronal and extraneuroal uptake and catechol-O-methyltransferase, respectively. A resting tension of 2 g was applied to the stripes and after 60 minutes of equilibration (with washouts and readjustment to 2 g every 20 min), a cumulative concentration-response curve to norephinephine (0.01-100 μM) was performed to establish the EC50 (50% of the maximal response) and maximal response of the strips. After washouts and one hour of reequilibration, the strips were exposed to a fixed concentration of 30 μM norepinephrine (approximately the EC50 value). After achieving a stable plateau of contraction, diazepam (0.1 - 100 μM), sildenafil (1 nM - 100 μM) and solvent control (0.1 M DMSO) were tested in separate time-matched strips. At the end of the test phase, the maximal relaxant capacity was checked by the addition of 100 μM papaverine. [0043] Local delivery of diazepam was shown to be very effective in relaxing rabbit isolated corpus cavernosum in a concentration-dependent manner. The maximal relaxant effect of diazepam was similar to the maximal relaxant effect of sildenafil (Viagra). Example 3 - In vivo effect of local delivery of diazepam on subjects suffering from ED [0044] Example 3 A: A male in his 40 's presented with symptoms typical of ED and was treated with a composition as shown in Table 1 with a 2% diazepam gel formulation which contained PLO and DMSO as carrier excipients. This composition was administered topically on his penis. He recovered erectile function. Repeated treatments continue to be effective. No adverse effects have been observed.

[0045] Example 3B: A male in his 70's presented with symptoms typical of ED and was treated with a composition as shown in Table 1 with a 1% diazepam gel formulation containing PLO as a carrier. This composition was administered topically on his penis. He recovered erectile function. Repeated treatments continue to be effective. No adverse effects have been observed.

[0046] Example 3C: A male in his 5O'sj)resented with symptoms typical of ED and was treated with a composition as shown in Table 1 with a 3% diazepam gel formulation containing PLO and DMSO as carrier excipients. This composition was administered topically on his penis. He recovered erectile function. Repeated treatments continue to be effective. No adverse effects have been observed.

[0047] Examples 3A-3C above demonstrate that local administration of diazepam to the penis of human males affected by ED facilitates the recovery of erectile function without any apparent adverse effects.

Claims

We claim:

1. A method for preventing, treating or reducing the severity of male erectile dysfunction, which method comprises: administering an effective amount of diazepam topically to the penis of a male mammal for whom such prevention, treatment or reduction of severity is needed or desirable.

2. The method of claim 1 , wherein the mammal is a human.

3. The method of claim 1, wherein diazepam is administered at an effective time prior to sexual activity.

4. The method of claim 3, wherein said effective time comprises from about 30 minutes to about 24 hours prior sexual activity.

5. The method of claim 1, wherein following said administration combined plasma level of diazepam and desmethyldiazepam does not exceed about 100ng/ml.

6. The method of claim 5, wherein following said administration the combined plasma level of diazepam and desmethyldiazepam does not exceed about 50ng/ml.

7. The method of claim 6, wherein following said administration the combined plasma level of diazepam and desmethyldiazepam does not exceed about 25ng/ml.

8. The method of claim 1 , wherein the effective amount of diazepam is less than about 50mg.

9. The method of claim 8, wherein the effective amount of diazepam comprises from about lmg to about 30mg.

10. The method of claim 9, wherein the effective amount of diazepam comprises from about 5mg to about 20mg.

11. The method of claim 8, wherein said effective amount of diazepam is less than about 5mg.

12. A pharmaceutical composition for the prevention, treatment or reduction of severity of male erectile dysfunction comprising: diazapem and pharmaceutically acceptable excipients, wherein such dosage form is suitable for topical administration.

13. The pharmaceutical composition of claim 12 in a form selected from the group consisting of suppositories, ointments, solutions, gels, sprays, creams, suspensions, liquids, powders and pastes and any combination thereof.

14. The pharmaceutical composition of claim 13 in the form of a gel.

15. The pharmaceutical composition of claim 14, wherein the gel is a matrix-based gel.