INHALATION DEVICES AND RELATED METHODS FOR ADMINISTRATION OF SEDATIVE HYPNOTIC COMPOUNDS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. provisional application no. 61/203,560 filed 23-December 2008 entitled "Inhalation Devices and Related Methods for Administration of Sedative Hypnotic Compounds" which is hereby incorporated by reference in its entirety.

FIELD

[0002] Described herein are formulations and devices for inhalation administration of sedative compounds. Specifically, formulations and devices that aerosolize sedative compounds for the treatment insomnia, including sleep onset and sleep maintenance are described. Methods and kits for treating insomnia are also described.

BACKGROUND

[0003] Insomnia is a common sleep disturbance that affects the quantity or quality of sleep. Insomnia may be acute (one to several nights) or chronic (months to years). The symptoms of insomnia are typically described as an inability to fall asleep (sleep onset insomnia) or remain asleep (sleep maintenance insomnia). In some instances, insomnia is associated with other medical conditions, such as anxiety and depression, or with use of certain medications. According to the National Sleep Foundation's Sleep in America Poll 2005, insomnia was a concern because the effects of sleep deprivation were reported to decrease the quality of life of the individual, and in some cases, compromise the safety and normal functioning of the individual in the workplace and while driving.

[0004] The current treatment of insomnia will vary depending on the etiology, nature, and severity of symptoms, and may include the use of pharmacologic agents. These agents typically are sedative compounds that include, but are not limited to: barbiturates, benzodiazepines, non-benzodiazepine sedatives (i.e. imidazopyridine class (Zolpidem), pyrazolopyrimidine class (zaleplon) and pyrrolopyrazine class (eszopiclone)), GABA _A receptor agonists, antihistamines, orexin receptor agonists, phenothiazines, melatonin, and melatonin MTl and MT2 receptor agonists. As used herein, the terms "sedative", "hypnotic", "sedative hypnotic" and similar words or phrases are to be understood to be synonymous and refer to the ability to induce sleep.

[0005] Currently, oral nonbenzodiazepines such as Ambien® tablets (Zolpidem tartrate) (Sanofi-Aventis, Bridgewater, NJ), Lunesta® tablets (eszoplicone) (Sepracor, Marlborough, MA), and Sonata® capsules (zaleplon) (King Pharmaceuticals, Bristol, TN).

[0006] Other nonbenzodiazapine treatments, all orally administered, which may include melatonin (OTC) and the melatonin receptor MT ₁ ZMT ₂ agonist Rozerem® tablets (ramelteon) (Takeda Pharmaceutical Co., Ltd., Osaka, Japan), are frequently prescribed for sleep disturbances.

[0007] Developmental compounds include the nonbenzodiazapine GABA _A agonist, Indiplon (Neurocrine, San Diego, CA) and those with novel receptor activity such as HYl 0275 which is a dual-acting H ₁ ZS-HT ₂ A compound (HypnionZLilly, Lexington, MA) and almorexant, an orexin receptor antagonist (ActelionZGSK, Basel, Switzerland). These newer therapies minimize or avoid undesirable side effects typical of the GABA _A agonists, such as memory impairment and dependence and abuse potential, tolerance and rebound insomnia.

[0008] All of these compounds are administered orally, and therefore can take from 1-2 hours to onset of therapeutic effects. Food or alcohol intake can significantly enhance or retard the therapeutic effects or time to onset. Because of the long time to onsets, the long duration of effects and the variability with GI loading, these therapies must be administered on a specific schedule hours before retiring for a normal sleep period. Because oral bioavailability can be low, relatively high doses are required to achieve and sustain systemic circulation concentrations sufficiently high to be effective, particularly for sleep maintenance. Such high dosage levels, combined with the long half lives of elimination typical of these compounds, result in long washout periods which can prolong residual sedation into normal waking hours.

[0009] Given the importance of the sedative-hypnotics in treating insomnia, an alternative to oral administration would be desirable to administer sedative hypnotics by means that would have rapid onset and could be administered just before retiring for normal sleep period. Devices for generating aerosols of sedative- hypnotic drugs for inhalation would enable rapid onset because therapeutically effective concentrations can be achieved rapidly by pulmonary administration. Additionally inhalation avoids interference from food or drink that is found with oral administration. Inhalation also bypasses first pass metabolism and results in higher bioavailability for small molecules such as the sedative-hypnotics. Therefore lower doses can be used to rapidly achieve therapeutic concentrations in systemic circulation in as fast as 2- 3 minutes. The lower doses minimize side effects and residual sedation at the end of sleep period.

SUMMARY

[0010] The invention described herein includes formulations, methods, inhalation devices and kits for the treatment of sleep disturbances. The devices generally include a housing, an aerosol generating mechanism, and a sedative composition. The preferred inhalation device is a pressurized metered dose inhaler (pMDI). The pMDI may be breath- actuated.

[0011] The sedative compositions may include any barbiturates, benzodiazepines, non-benzodiazepine sedatives, GABA _A receptor agonists, antihistamines, orexin receptor agonists, phenothiazines, melatonin, and melatonin MT ₁ and MT ₂ receptor agonists, 5-HT ₂ A antagonists, or combinations thereof that are useful for treating sleep disturbances. In addition to the sedative, excipients such as solvents, dispersants, preservatives, antioxidants, buffering agents, and flavoring agents may be used in the compositions. The sedative composition may be contained in pressurized metered dose inhaler (pMDI) within a pressurized reservoir fitted with a metering valve as a particle suspension or solution in a fluorocarbon propellant media.

[0012] The formulations, methods, and inhalation devices may be used to treat various sleep disturbances. For example, the formulations, methods, and inhalation devices may be used to treat insomnia, including acute insomnia, chronic insomnia, sleep onset insomnia, and sleep maintenance insomnia. In some embodiments of the invention, the aerosol generated by the inhalation device is capable of rapidly initiating sleep, thus decreasing sleep latency. As used herein, the terms "rapid" or "rapidly" refer to the induction of sleep within at least about 30 minutes after administration of the sedative. In other embodiments, the aerosol of the formulation is also capable of maintaining sleep for at least about 4 hours. In another embodiment, a drug combination may be administered, where one drug provides rapid induction of sleep, and the other drug provide longer-acting sedation for sleep maintenance, but not so long as to cause residual sedation at the end of the sleep period.

[0013] The inhalation devices may be disposable, single-use or multiple-use devices. They may also be packaged as kits including one or more inhalation devices and one or more sedative compositions. Here the sedative compositions may each include a different dose. The kits may also be tailored to the type of insomnia being treated.

DETAILED DESCRIPTION

[0014] Described herein are formulations, methods, inhalation devices and kits for treating sleep disturbances. As previously mentioned, the sleep disturbance that may be treated is insomnia, including without limitation, acute insomnia, chronic insomnia, sleep onset insomnia, and sleep maintenance insomnia. The inhalation devices will generally be configured to have a housing, an aerosol generating mechanism, and a sedative formulation. Said formulation, which includes at least one sedative-inducing medicament, when administered via pulmonary inhalation, preferably induces sleep in less than 30 minutes, more preferably further maintains that sleep for at least 4 hours and most preferably further limits that sleep so that there is little or no residual sedation after the normal sleep period. The dosage of each of the sedatives used is configured to provide a T _max equal to or less than 20 minutes. In some variations, the devices include a dose counter and lock-out mechanism. Features that control airflow and/or plume deposition may also be employed.

I. DEVICES

[0015] The inhalation device may be of various designs, so long as they are capable of generating an aerosol of a sedative formulation for treating sleep disturbances. In the preferred embodiment, the inhalation device is a pMDI. Pressurized Metered Dose Inhalers

[0016] pMDIs generally have two components, a canister in which the drug formulation is stored under pressure as a suspension or a solution, and a receptacle which is used to hold and actuate the canister. The canister may contain multiple doses of the formulation, although it is possible to have single dose canisters as well. The canister typically includes a valved outlet from which the contents of the canister can be discharged. Aerosolized drug is dispensed from the pMDI by applying a force on the canister to push it into the receptacle thereby opening the valved outlet and causing the drug formulation to be conveyed from the valved outlet through the receptacle outlet. Upon discharge from the canister, the drug formulation is atomized, forming an aerosol containing the medicament. pMDIs use propellants to pressurize the contents of the canister and to propel the drug formulation out of the receptacle outlet. In pMDIs, the composition may be provided in liquid form, and resides within the canister along with the propellant. The composition can also be a solution wherein the medicament is soluble in the propellant alone or in combination with one or more co-solvents. The propellant may take a variety of forms. For example, the propellant may be a compressed gas or liquefied gas. In the past, commonly used liquid propellants included chlorofluorocarbons (CFC) which are now banned. CFCs have almost completely been replaced by hydrofluroralkane (HFA) propellants.

[0017] In some instances, the discharge of aerosolized drug must be coordinated with inhalation, so that the aerosolized drug is entrained within the inspiratory air flow and conveyed to the lungs. In other instances, a breath-actuated trigger, such as that included in the Tempo® inhaler (MAP Pharmaceuticals, Mountain View, CA) may be employed that automatically discharges a dose of drug upon sensing inhalation.

[0018] Detailed descriptions of the Tempo® inhaler may be found, for example, in U.S. Patent Nos. 5,954,047; 6,026,808; 6,095,141; and 6,367,471 which are hereby incorporated by reference in their entirety.

II. COMPOUNDS

[0019] The present invention is the treatment or reduction in symptoms of the various sleep disturbances described herein by administering via pulmonary inhalation formulation incorporating various medicaments which can include but are not limited to barbiturates, benzodiazepines, non-benzodiazepines, GABA _A receptor agonists, antihistamines, orexin receptor agonists, phenothiazines, melatonin, melatonin MTi and melatonin MT ₂ receptor agonists, their derivatives, and combinations thereof, as described herein.

[0020] Specifically, barbiturates include without limitation amobarbital, butobarbital and secobarbital. Benzodiazepine site modulators such as GABA-receptor agonists may be used. Suitable GABA receptor agonists that may be employed include without limitation, cyclopyrrolones such as eszopiclone, pyrazolopyrimidines such as zaleplon, imidazo[l,2- α]pyrimidines such as Zolpidem, combinations, salts, acids, derivatives, and analogs thereof. The GABA-receptor agonists may have short-acting or long-acting effects.

[0021] Eszopiclone is a short-acting nonbenzodiazapine hypnotic agent. It is the dextrarotatory isomer of 6-(5-chloro-2-pyridyl)-5[(4-methyl-l-piperazinyl)carbonyloxy ]-7- oxo-6,7-di hydro-5H-pyrrolo[3,4-b]pyrazine, also known as zopiclone. Properties of eszopiclone and its pharmaceutically acceptable salts, salts of organic acids, organic acids, and derivatives thereof, as well as the preparation of these compounds are disclosed in U.S. Patent Nos. 6,319,926; 6,864,257; 6,444,673; 6,864,257; 7,125,874; and 7,381,724.

[0022] Zaleplon is also a short-acting nonbenzodiazepine hypnotic agent. It is also known as (N-[3-(3-cyanopyrazolo[l ,5a]pyrimidin-7-yl)phenyl]-N-ethylacetamide). Properties of zaleplon as well as its preparation are disclosed in U.S. Patent No. 4,626,538. A crystalline form of zaleplon, which may also be employed in the compositions described herein, is described in U.S. Publication No. 2002/0072527.

[0023] Zolpidem is another short-acting nonbenzodiazepine hypnotic agent. It is also known as N,N,6-trimethyl-2-(4-methylphenyl)imidazo [ 1 ,2-α]pyridine-3 -acetamide. Properties of Zolpidem and its pharmaceutically acceptable salts and derivatives, as well as the preparation of these compounds are disclosed in GB Nos. 991,589 and 1,076,089, and U.S. Patent Nos. 4,382,938; 4,460,592; 4,492,695; and 6,242,460.

[0024] In another embodiment of the invention, a melatonin receptor agonist is used to treat sleep disturbances. A suitable melatonin receptor agonist is ramelteon, which is a hypnotic agent, chemically designated as (5)-N-[2-(l,6,7,8-tetrahydro-2H-indeno-[5,4- ό]furan-8-yl)ethyl]propionamide. Properties of ramelteon and its pharmaceutically acceptable salts and derivatives, as well as the preparation of these compounds are disclosed in U.S. 6,034,239 and WO 97/32871. Other examples of a suitable melatonin receptor agonist include melatonin itself, Rozerem® (Takeda), tasimelteon aka VEC- 162 (Vanda Pharmaceuticals, Inc.) and drugs acting on the serotonin system such as Eplivanserin (Sanofi- Aventis).

[0025] In another embodiment of the invention, antihistamines are used to treat sleep disturbances. Antihistamines are classically understood to function as histamine agonists and especially those that act on the H ₁ receptor. Antihistamines can include, but are not limited to diphenhydramine, loratadine, desloratadine, meclizine, fexofenadine, pheniramine, cetirizine, and promethazine

[0026] In another embodiment of the invention, phenothiazines are used in the formulation of the invention to treat sleep disturbances. This class of compounds is based upon the parent compound phenothiazine, which is a yellow tricyclic compound which is soluble in acetic acid, benzene, and ether. Phenothiazine derivatives are classified into three groups that differ with respect to the substituent on the sole nitrogen atom: the aliphatic compounds (bearing acyclic groups), the "piperidines" (bearing piperidine-derived groups), and the piperazine (bearing piperazine-derived substituents). Phenothiazines can include, but are not limited to promazine, chlorpromazine, mesoridazine, thioridazine, perphenazine and flupexitxol.

[0027] In another embodiment of the invention, orexin receptor is used in the formulation of the invention to treat sleep disturbances. Such antagonists could include almorexant which is being developed by Actelion Pharmaceuticals LTD as an oral therapy.

[0028] In another embodiment of the invention, a 5-HT ₂ A antagonist is used in the formulation of the invention to treat sleep disturbances. III. PHARMACEUTICAL COMPOSITIONS AND DOSAGE FORMS

[0029] In some embodiments of the invention, the sedative formulations of the invention may include a benzodiazepine site modulator, as described above. Benzodiazepine site modulators directly or indirectly bind to the GABA (gamma-aminobutyric acid) receptor to potentiate the action of GABA (an inhibitory neurotransmitter). Examples of benzodiazepine site modulators that may be used in the sedative compositions include, but are not limited to eszopiclone, zaleplon, Zolpidem, combinations, and salts, acids, derivatives, and analogs thereof. The compositions may also contain one or more inactive substances such as antioxidants, buffers, preservatives, flavoring agents, etc. Depending on the whether the composition is a solution, dispersion, or a suspension, pharmaceutically acceptable solvents, propellants, carriers, dispersants, etc., may also be used.

[0030] In other embodiments of the invention, the sedative formulations of the invention, described herein, may include a melatonin receptor agonist. Here the composition may also include one or more inactive substances such as antioxidants, buffers, preservatives, flavoring agents, etc. As also mentioned above, depending on the whether the composition is a solution, dispersion, or suspension, pharmaceutically acceptable solvents, propellants, carriers, dispersants, etc., may be used.

[0031] In yet further embodiment of the invention, the sedative formulation of the invention may include combinations of benzodiazepine site modulators, a combination of a benzodiazepine site modulator and a benzodiazepine or a melatonin receptor agonist, or a combination of a melatonin receptor agonist and a benzodiazepine. The combination therapy may be useful when an individual suffers from both sleep onset insomnia and sleep maintenance insomnia because a rapid and/or short-acting agent may be used with a longer- acting agent. For example, eszopiclone may be combined with zaleplon.

[0032] The following table contains examples of some of medicaments that could be used in formulations of the present invention.

[0033] Half Life Duration of Action

Drug

(hours) (hours)

Chlordiazepoxide 7-13 24-28

Diazepam 30-56 24-28

Flurazepam 50-100 24-28

Lorazepam 9-19 12-18

Oxazepam 6-10 12-18

Temazepam 5-17 12-18

Triazolam 2-4 <6

Alprazolam 9-14 <6

Midazolam 1.3-2.5 4

Lormetazepam 10 12-18

Nitrazepam 28 24

Clonazepam 18-28 24-28

Zolpidem 2 <4

Eszopiclone 6 8

[0034] When a benzodiazepine is used in the sedative formulation of the invention, exemplary benzodiazepines that may be employed include, but are not limited to alprazolam, bromazepam, camazepam, chlordiazepoxide, clobazam, clorazepic acid, clotiazepam, cloxazolam, diazepam, ethyl loflazepate, etizolam, fludiazepam, flutazolam, flutoprazepam, halazepam, ketazolam, lorazepam, medazepam, metaclazepam, mexazolam, nordazepam, oxazepam, oxazolam, pinazepam, prazepam, tofisopam, salts, acids, derivatives, and analogs thereof.

[0035] In another embodiment of the invention, the sedative formulation of the invention is a liquid composition for use with a pMDI, and may include a benzodiazepine site modulator or a melatonin receptor agonist, a propellant and/or one or more cosolvents, surface modifying agents or surfactants. Suitable propellants include, but are not limited to, dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, and hydro fluoroalkanes. Hydrofluoroalkanes include 1,1,1,2-tetrafluoroethane or 1,1,1,2,3,3,3- heptafluoropropane.

[0036] A further embodiment would include a benzodiazepine site modulator, a melatonin receptor agonist, and benzodiazepine. Any amount of the benzodiazepine site modulator, melatonin receptor agonist, and benzodiazepine may be included in the sedative compositions. For example, they may be included in amounts of about 1% to about 99% by weight of the composition. In one embodiment, the active agents are included in an amount of about 1% to about 90% by weight, about 1% to about 80% by weight, about 1% to about 70% by weight, about 1% to about 60% by weight, about 1% to about 50% by weight, about 1% to about 40% by weight, about 1% to about 30% by weight, about 1% to about 20% by weight, about 1% to about 10% by weight, or about 1% to about 5% by weight of the composition. It is understood that the above amounts are exemplary, and that there may be instances in which higher or lower amounts may be used.

IV. METHODS OF ADMINISTRATION

[0037] The sedative formulations described here may be administered by inhalation using devices such as a pMDI with or without a breath-actuation feature. In general, a user first completely exhales and then inhales through the mouthpiece, establishing air flow through the device. In the case of a breath actuated device, the device will automatically discharge the drug after the user begins to inhale. In the case of a conventional pMDI device, the user will press the canister to discharge a dose and simultaneously inhale to administer the dose. In either case, the user continues to inhale to fill their lungs to capacity after the discharge and then may hold their breath for a period of time to allow the aerosolized drug to settle within the airways of the lungs.

[0038] The active agents in the sedative formulations may be provided in many dosage ranges. For example, each inhalation may provide a dose from about 0.05 mg to about 20 mg of the active agent. In some embodiments, the dose may range from about 0.25 mg to about 10 mg. In other embodiments, the dose may range from about 1.0 mg to about 7.0 mg. In further embodiments, the dose may range from about 2.0 mg to about 5.0 mg of the active agent.

[0039] The dosing regimen employed may depend on a number of factors, such as the type of insomnia being treated, particular active agent being used, severity of symptoms, and whether the insomnia is due to an underlying medical condition, hi general, the sedative composition may be administered once a day when sleep is desired. However, administration may be repeated if it safe to do so. In some embodiments the drug may be administered at the start of the normal sleep period and can be administered again if the user awakens in the middle of the sleep period. V. KITS

[0040] The inhalation devices and sedative compositions may be provided in a kit. The kits may contain devices containing one or more of the sedatives described herein. In one particular embodiment, the kit would include an inhalation device as described herein; the sedative formulation would include a benzodiazepine site modulator or melatonin receptor agonist, or a combination thereof. Some kits will include one or more sedative formulations and one or more pMDIs. The included compositions may contain the active agents in the same or different doses. Instructions may be in printed, included photographs, and/or pictographic depictions of how to use the device. In addition, the instruction can be on recorded media including audio tape, audio CD, video tape, DVD, CD-ROM, or the like.

[0041] The kits can be designed to target specific types of insomnia, hi one embodiment, the kit is designed for use with sleep onset insomnia. Such a kit may include one or more short-acting agents. In another variation, the kit is designed for use with sleep maintenance insomnia, which may include both a short-acting agent in addition to a long- acting agent.

VI. EXAMPLES

[0042] Pressurized Metered Dose Inhaler examples

[0043] Example 1 - Zolpidem

71.25 mg Zolpidem

14.25 mL hydrofluoroalkane propellant (HFA- 134a or HFA-227 or a mixture thereof)

19 mL aluminum canister with or without a polymeric coating.

A closure system with a metering chamber capable of metering fixed volumes. For instance, a 100 mcL valve used in conjunction with the above formulation and components would emit a dose of Zolpidem approximately equal to 0.5 mg. [0044] Example 2 - Zaleplon

142. 5 mg zaleplon

14.25 mL hydrofluoroalkane propellant (HFA- 134a or HFA-227 or a mixture thereof) 19 mL aluminum canister with or without a polymeric coating. A closure system with a metering chamber capable of metering fixed volumes. For instance, a 100 mcL valve used in conjunction with the above formulation and components would emit a dose of zalepon approximately equal to 1 mg.

[0045] Example 3 - Ramelteon

[0046] Ramelteon is typically administered by oral tablet, and the active agent is converted to the major metabolite in the liver. Oral bioavailability of ramelteon is 1.8% due to extensive hepatic transformation. The metabolite, Mil, is less active but circulates at higher concentrations, and may also be a more potent carcinogen.

[0047] As pulmonary delivery bypasses first pass metabolism, doses can be lower. Considering a mean functional activity of Mil at 21 times lower potency than ramelton, typical inhaled doses entering the systemic circulation of ramelteon would need to be in the 0.25-2 mg range, ideally 0.5 mg

[0048] Therefore, a suitable pMDI formulation would be as follows:

50 mg ramelteon

10 mL hydrofluoroalkane propellant (HFA- 134a or HFA-227 or a mixture thereof)

14 mL aluminum canister with or without a polymeric coating.

A closure system with a metering chamber capable of metering fixed volumes. For instance, a 100 mcL valve used in conjunction with the above formulation and components would emit a dose of ramelteon approximately equal to 0.5 mg.

[0049] Example 4 Eplivaαserin

[0050] 200 mg eplivanserin

8.95 mL hydrofluoroalkane propellant (HFA- 134a or HFA-227 or a mixture thereof)

10 mL aluminum canister with or without a polymeric coating.

A closure system with a metering chamber capable of metering fixed volumes. For instance, a 100 mcL valve used in conjunction with the above formulation and components would emit a dose of eplivanserin approximately equal to 2mg.

[0051] While certain embodiments have been described herein, it will be understood by one skilled in the art that the methods, systems, and apparatus of the present disclosure may be embodied in other specific forms without departing from the spirit thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive of the present disclosure. Rather, the scope and spirit of the present invention is embodied by the appended claims.