Patent Application
20110233043
This disclosure relates to devices capable of entraining a substance into an airflow, to articles and methods employing such devices, and in particular to articles and methods of producing multiple doses of a condensation aerosol of a drug having high purity, high yield, characterized by a particle size distribution suitable for inhalation delivery, and which can be administered to a user during a single inhalation.
Pulmonary delivery is known as an effective way to administer physiologically active compounds to a patient for the treatment of diseases and disorders. Devices developed for pulmonary delivery generate an aerosol of a physiologically active compound that is inhaled by a patient where the compound can be used to treat conditions in a patient's respiratory tract and/or enter the patient's systemic circulation. Devices for generating aerosols of physiologically active compounds include nebulizers, pressurized metered-dose inhalers, and the dry powder inhalers. Nebulizers are based on atomization of liquid drug solutions, while pressurized metered-dose inhalers and dry powder inhalers are based on suspension and dispersion of dry powder in an airflow and/or propellant.
Aerosols for inhalation of physiologically active compounds can also be formed by vaporizing a substance to produce a condensation aerosol comprising the active compounds in an airflow. A condensation aerosol is formed when a gas phase substance formed from vaporization condenses or reacts to form particulates (also called particles herein) in the air or a gas. Examples of devices and methods employing vaporization methods to produce condensation aerosols are disclosed in U.S. Pat. Nos. 6,682,716; 6,737,042; 6,716,415; 6,716,416; 6,740,307; 6,740,308; 6,737,043; 6,740,309; and 6,716,417, each of which is incorporated herein by reference.
It can be desirable that an inhalation device be capable of delivering multiple doses of a physiologically active compound and that each dose comprising the active compound be administered to a patient during a single inhalation. A dose refers to the amount of a substance released during one activation of an inhalation device. A dose can comprise, for example, a therapeutically effective amount of a physiologically active compound. Furthermore, treatment regimens can require that each of the multiple doses delivered to a patient comprise a controlled amount of a physiologically active compound, and that the active compound administered exhibit high purity and be free of byproducts, e.g., excipients. Optimal delivery of a dose to a patient's respiratory tract, and in particular to a patient's lungs, can also be facilitated by the aerosol having a mass median aerodynamic diameter of less than about 4 μm. Furthermore, practical considerations make it desirable that a substantial amount of each dose contained in the device, form an aerosol, be emitted from the device, and be inhaled by the patient.
When a condensation aerosol is formed in an airflow, a certain portion of the aerosol can deposit on downstream physical features such as the side walls of the airway defining the airflow, the mouthpiece of the device, or other structures and thereby reduce the amount of active compound emitted by the device and available for administration. In multiple dose devices, packaging the multiple doses within a common airway can be attractive for producing low cost and compact products. However, in multiple dose devices, where the multiple doses are disposed on surfaces within an airflow, a certain amount of an aerosol particles formed by vaporizing an upstream dose, can deposit onto downstream surfaces comprising unvaporized compound. Not only can the deposition on unvaporized doses reduce the amount of active compound emitted from the device, but in addition, the deposition can change the amount of active compound forming subsequent doses. Thus, particularly where a device includes a large number of multiple doses, the latter doses can comprise a variable and uncontrolled amount of an active compound.
For many treatment regimens, the ability to deliver a dose comprising a precise, consistent, and reproducible amount of a physiologically active compound can impact the therapeutic efficacy of the treatment regimens, and in some cases, such a capability can also enable new therapies. Thus, there is a need for inhalation devices and methods of producing a condensation aerosol that can repeatedly deliver precise, reproducible and/or controlled amounts of a physiologically active substance.
Certain embodiments include devices for entraining a substance within an airflow comprising an airway with an inlet, and an outlet; at least one support disposed within the airway; the substance disposed on the at least one support; and a mechanism configured to release the substance from the at least one support; wherein an airflow passing from the inlet to the outlet is directed to the at least one support such that the substance is entrained in the airflow when released from the support.
Certain embodiments include electrically resistive heating elements comprising a metal foil for vaporizing a substance disposed thereon to produce a condensation aerosol comprising the substance.
Certain embodiments include devices for delivering a condensation aerosol to a subject comprising a dispensing unit and a separable cartridge. In certain embodiments, the dispensing unit comprises a first housing comprising a receptacle for a separable cartridge; a controller for controlling vaporization of the substance; and a power source. In certain embodiments, the separable cartridge comprises a second housing; an airway contained within the housing having an inlet, and an outlet; a mouthpiece coupled to the outlet; an air bypass hole coupled to the outlet; at least one electrically resistive heating element disposed within the airway; a substance disposed on the at least one heating element; and an actuation mechanism configured to transfer energy from the power source to the at least one heating element; wherein an airflow from the inlet to the outlet of the airway causes the substance to vaporize and condense in the airflow to form a condensation aerosol.
Certain embodiments include methods of entraining a vaporized substance or aerosol particles into an airflow, methods of producing a condensation aerosol, and methods of administering a substance to a subject using the devices disclosed herein. For purposes herein, “entrain” or “entraining” means to direct, lift, draw in or along, inject, transport, carry, or suspend a vaporized substance or aerosol particle into an airflow.
Other embodiments will be apparent to those skilled in the art from consideration and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of certain embodiments, as claimed.
Unless otherwise indicated, all numbers expressing quantities and conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.”
In this application, the use of the singular includes the plural unless specifically stated otherwise. In this application, the use of “or” means “and/or” unless stated otherwise. Furthermore, the use of the term “including,” as well as other forms, such as “includes” and “included,” is not limiting.
Condensation aerosols can be formed when a gaseous substance condenses or reacts to form particulates in air or a gas. A gaseous substance can be produced when a solid or liquid substance is thermally sublimed or vaporized. Vaporization refers to a phase transition in which a substance changes from a solid or liquid state into a gaseous state. Sublimation refers to a phase transition in which a substance passes directly from a solid state to a gaseous state.
Upon entering an airflow, a gaseous substance can cool and, at least in part depending on the temperature of the airflow, can condense to form an aerosol particle. Condensation aerosol particles not sufficiently entrained within the airflow have a greater probability of falling out of the airflow to deposit on a downstream surface.
Inefficient entrainment of particulates within an airflow and subsequent deposition of the particulates on downstream surfaces is shown in
A schematic illustration of a device for entraining a particulate, and in particular an aerosol-forming gas phase substance, within an airflow is shown in
Another embodiment of a device for entraining a substance, and in particular, a gas phase substance, within an airflow to form a condensation aerosol is schematically illustrated in
Another embodiment of a device for entraining a substance or condensation particles within an airflow is shown in
In another embodiment, as shown in
How effectively a substance is entrained within an airflow can at least in part depend on the proportion of rate of airflow across the surface of a support, R1 to the rate of airflow through the plurality of openings, R2. The appropriate proportion R1:R2 for effectively entraining a substance within an airflow can depend on a number of factors such as the airflow velocity and the distance of the support from the center of the airflow. In certain embodiments, R1:R2 can range from 80:20 to 20:80 and in other embodiments can range from 60:40 to 40:60. The proportion R1:R2 can be established by the relative areas of the holes through which the first an second airflows pass. For example, referring to
Another embodiment of a device for entraining a substance in an airflow is shown in
In the embodiments shown in FIGS. 1B and 2A-D by introducing air from below the supports redeposition of the vaporized substance or aerosol condensation particles is minimized.
Different arrangements of the supports with respect to the airflow through the device are shown in
The concepts underlying the exemplary devices illustrated in
As shown in
When cartridge 50 is assembled, a structure 72 separates a first airway and a second airway. First airway 74 and second airway 76 are formed by structure 72 and the opposing inner walls of first and second shells 52, 54, respectively, as shown in the cross-sectional view of the assembled cartridge illustrated in
As shown in
A top view showing the positioning of plurality of holes 84 and set of slots 86 with respect to plurality of supports 78 is shown in
As shown in
A cartridge as described in
To deliver a condensation aerosol to a subject, the subject places mouthpiece 56 of condensation aerosol delivery device 100 into his or her mouth. The subject then inhales on mouthpiece 56 to generate an airflow as described herein. When a certain minimum airflow or a rate in change in airflow is sensed, the device is triggered. A signal from the airflow sensor is sent to the controller to cause the battery power source to connect to at least one support. As described herein, the supports can be, for example, electrically resistive heating elements. Heat produced by the electrically resistive heating element thermally vaporizes the substance disposed thereon. The vaporized substance condenses in the airflow to form condensation particles and hence, a condensation aerosol. As described herein, the airflow passing from beneath the heating element causes the substance vaporized from the heating element or the condensed aerosol particles to become entrained in the airflow as opposed to depositing on other supports prior to passing through the cartridge. The aerosol upon passing through the cartridge is subsequently inhaled by the subject. Activation of the condensation aerosol delivery device, generation of the condensation aerosol, and inhalation of the condensation aerosol can occur in a single breath. The inhaled condensation aerosol then enters the subject's respiratory tract where the condensation aerosol comprising the active substance can be deposited in the respiratory tract, and in particular the pulmonary alveoli, of the subject.
A device for generating a condensation aerosol can include at least one support and in certain embodiments, for example, as shown in
Selection of the appropriate material for forming the support can also, at least in part, be determined by the source of energy used to release the substance from the support. For example, the source of energy used to release the substance can be mechanical, acoustic, radiation such as microwave, radio frequency or optical, and/or thermal. When the applied energy is absorbed directly by the substance, the support can be non-thermally conductive. For example, an optical source can be used to ablate and/or vaporize a substance disposed on a support. Alternatively, in certain embodiments, it can be more efficient or practical to heat a thermally conductive support which transfers thermal energy to the substance disposed thereon to release the substance from the support. In such embodiments, the support can be a thermally conductive material such as a metal, a metal alloy, a metal composite having more than one layer and/or composition, graphite, or the like. For example, in certain embodiments the metal can be stainless steel, copper, nickel, aluminum, gold, or silver, and can be plated with one or more of the foregoing materials or other metals. In some embodiments, the thickness of the plating of a metal layer on the metal can be within the range of between 0.001 μm to 3 μm and in other embodiments. In some embodiments, the support can be a semi-conducting material.
In certain embodiments, for example, where the condensation aerosol delivery device is designed for portable use with a battery power source, efficient energy use can be desirable. Minimization of the energy used to release a substance from a support can, at least in part, depend on the shape and dimensions of the support, the materials forming the support, and the placement of the support within the airway. In certain embodiments, the support can comprise an electrically resistive material such as a foil. In certain embodiments, the foil can be a stainless steel foil and can include a layer of one or more materials such as a gold layer to facilitate, for example, forming an electrical connection, and/or modifying the electrical properties such as the resistance of a portion of the foil. The appropriate dimensions for a foil can depend at least in part, on the desired resistance, the amount of substance disposed on the support, the amount of energy needed to vaporize the substance disposed on the support, and/or on mechanical stability considerations.
To maximize transfer of thermal energy produced by the support to the substance disposed thereon, it is desirable that a thermally conductive support be thermally isolated. Minimizing the contact area between the support and the connector helps to thermally isolate the support. As shown, for example, in
Particularly for portable, battery operated condensation aerosol delivery devices, it can be useful to minimize the amount of power used to vaporize a substance. Several characteristics of the metal foil can be chosen to facilitate the efficient thermal vaporization of a substance from a metal foil, including, but not limited to, the thickness of the metal foil, the impedance of the metal foil, and the ratio of the surface area to the thermal mass of the metal foil. In certain embodiments, the thickness of the metal foil can be less than 0.01 inches, in certain embodiments, less than 0.001 inches, and in certain embodiments, less than 0.0005 inches. To minimize power dissipation in the electrical circuit and thereby maximize power delivered to the heating element, it can be desirable that the impedance of the metal foil be closely matched to the impedance of the power source. For example, in certain embodiments, the difference between the impedance of the resistive heating element and the impedance of the power source can be less than 50% of the impedance of the power source, in certain embodiments, less than 10% of the impedance of the power source, and in certain embodiments, less than 2% of the impedance of the power source. To facilitate the efficient transfer of thermal energy produced by the resistive heating element to the substance disposed thereon, it can be useful to maximize the ratio of the surface area of the resistive heating element to the thermal mass of the resistive heating element. Accordingly, in certain embodiments the ratio of the surface area of the heating element to the thermal mass of the resistive heating element can be greater than 10 cm2/J/° C., in certain embodiments, greater than 100 cm2/J/° C., and in certain embodiments, greater than 500 cm2/J/° C.
Low ratios of the surface area of the heating element to the thermal mass of the resistive heating element can facilitate the transfer of heat to the substrate, and lead to rapid thermal vaporization of the substance. Rapid thermal vaporization of a substance can minimize thermal degradation of the substance during vaporization and thereby maximize the purity of the condensation aerosol formed therefrom. For example, in certain embodiments, the support, and in particular, a metal foil can be heated to a temperature of at least 250° C. in less than 500 msec, in certain embodiments, to a temperature of at least 250° C. in less than 250 msec, and in certain embodiments, to a temperature of at least 250° C. in less than 100 msec.
Efficient transfer of thermal energy produced by the resistive heating element to the substance disposed thereon can further be facilitated by the substance being disposed on the surface as a thin layer. For example, in certain embodiments, the thickness of the layer of substance can range from 0.01 μm to 50 μm, in certain embodiments, can range from 0.01 μm to 20 μm, and in certain embodiments, can range from 0.01 μm to 10 μm.
The amount of energy to thermally vaporize a substance can be minimized by, for example, using an electrically resistive heating element comprising a thin metal foil, closely matching the impedance of the electrically resistive heating element to the impedance of the power source, maximizing the ratio of the surface area of the resistive heating element to the thermal mass of the resistive heating element, and using a thin film of substance disposed on the heating element. By appropriate design and selection of at least the foregoing parameters, in certain embodiments, the amount of energy to vaporize a substance from a support can be less than 250 joules, in certain embodiments, less than 50 joules, and in certain embodiments, less than 10 joules. In more specific embodiments, the amount of energy to vaporize one mg of substance from a support can be less than 250 joules, in certain embodiments, less than 50 joules, and in certain embodiments, less than 10 joules.
The number of supports forming a condensation aerosol delivery device and/or cartridge is not particularly limited. For example, in certain embodiments, a cartridge or drug delivery device can comprise from 1 to 200 supports, in certain embodiments, from 1 to 50 supports, and in certain embodiments, from 1 to 25 supports, and in certain embodiments, from 1 to 10 supports.
The cartridge can be separable from the condensation aerosol delivery device. In such embodiments, a subject can use the delivery device, for example, to administer more than one physiologically active substance, or more than one dose of the same physiologically active substance by replacing one cartridge with another. Also, when all the doses in a particular cartridge are exhausted, the user can obtain and insert a new cartridge into the delivery device.
While certain embodiments of the present disclosure can comprise a single support, it is contemplated that embodiments comprising a plurality of supports can be particularly useful in, for example, providing a convenient method of delivering multiple doses of a physiologically active compound or drug over a period of time. The terms physiologically active compound and drug are used interchangeably herein. As used herein, a drug refers to a substance recognized in an official pharmacopoeia or formulary, and/or a substance intended for use in the diagnosis, cure, mitigation, treatment or prevention of disease where disease refers to any disease, disorder, condition, symptom or indication. In such embodiments, the substance disposed on at least one support can comprise a therapeutically effective amount of a drug. For example, a therapeutically effective amount or dose of a drug can be disposed on a single support, on each of multiple supports, or on more than one support. In certain embodiments of a condensation aerosol delivery device, the same amount of physiologically active compound can be disposed on each support. In certain embodiments, different amounts of a physiologically active compound can be disposed on each of the plurality of supports, or a certain amount of active compound can be disposed on several supports, and a different amount of active compound on several other supports. Having different amounts of a drug on different supports can be useful in effecting treatment regimens where administering a variable amount of drug during a period of time is useful.
In certain embodiments, where the active compound disposed on several supports is an abusable substance, a second compound comprising an agonist can be disposed on one or more other supports. “Abusable substance” refers to a substance that can be improperly used, for example, by administering more than a prescribed or intended dosage, or by altering the route of administration from the intended route. For example, an opioid analgesic can be abused by using the opioid analgesic to elicit a euphoric effect, rather than therapeutically for the treatment of pain. Abusable substances include substances regulated by a regulatory agency focused on preventing drug abuse, such as, for example, the United States Drug Enforcement Agency (DEA). In certain embodiments, an abusable substance can be a substance listed on DEA schedule II, III, IV, or V. The second compound is a chemical compound that can act to reduce or to counteract the physiological activity and/or pharmacological effects of another chemical substance. Having both an abusable substance and a second compound capable of counteracting the effects of the abusable substance in the same device will complicate the ability of an abuser to selectively remove the abusable substance from heating elements. Proper use of the device would only allow the abusable substance to be activated in prescribed doses.
A substance to be released can be disposed on at least one surface of a support. For example, the substance can be disposed on the surface facing the center of the first airway and/or toward the part of the airflow where the velocity is highest. The substance can be applied to a surface of a support by any appropriate method and can depend at least in part on the physical properties of the substance and the final thickness of the layer to be applied. In certain embodiments, methods of applying a substance to a support include, but are not limited to, brushing, dip coating, spray coating, screen printing, roller coating, inkjet printing, vapor-phase deposition, spin coating, and the like. In certain embodiments, the substance can be prepared as a solution comprising at least one solvent and applied to a support. In certain embodiments, a solvent can comprise a volatile solvent such as acetone, or isopropanol. In certain embodiments, the substance can be applied to a support as a melt. In certain embodiments, a substance can be applied to a film having a release coating and transferred to a support. For substances that are liquid at room temperature, thickening agents can be admixed with the substance to produce a viscous composition comprising the substance that can be applied to a support by any appropriate method, including those described herein. In certain embodiments, a layer of substance can be formed during a single application or can be formed during repeated applications to increase the final thickness of the layer. In other embodiments, the substance can be applied on more than one surface of the support.
In certain embodiments, more than one active compound can be disposed on one or more of the plurality of supports. For example, a first active compound can be disposed on certain supports, and a second active compound can be disposed on other supports, and in certain embodiments, a composition comprising a first active compound and a second active compound can be disposed on one or more supports.
A dose can correspond to the amount of active compound released from a single support, or the amount of active compound released from more than one support. A dose or dosage as used herein refers to the amount of substance released during a single activation of a condensation aerosol delivery device. A dose can comprise a therapeutically amount of a physiologically active compound, meaning that the dose provides effective treatment of a condition and/or disease in a patient. The therapeutically effective amount of a physiologically active compound can vary from compound to compound, from subject to subject, and can depend upon factors such as the condition of the subject.
In certain embodiments, a substance disposed on at least one support can comprise a therapeutically effective amount of at least one physiologically active compound or drug. A therapeutically effective amount refers to an amount sufficient to effect treatment when administered to a patient or user in need of treatment. Treating or treatment of any disease, condition, or disorder refers to arresting or ameliorating a disease, condition or disorder, reducing the risk of acquiring a disease, condition or disorder, reducing the development of a disease, condition or disorder or at least one of the clinical symptoms of the disease, condition or disorder, or reducing the risk of developing a disease, condition or disorder or at least one of the clinical symptoms of a disease or disorder. Treating or treatment also refers to inhibiting the disease, condition or disorder, either physically, e.g. stabilization of a discernible symptom, physiologically, e.g., stabilization of a physical parameter, or both, and inhibiting at least one physical parameter that may not be discernible to the patient. Further, treating or treatment refers to delaying the onset of the disease, condition or disorder or at least symptoms thereof in a patient which may be exposed to or predisposed to a disease, condition or disorder even though that patient does not yet experience or display symptoms of the disease, condition or disorder. In certain embodiments, the amount of substance disposed on a support can be less than 100 micrograms, in certain embodiments, less than 250 micrograms, in certain embodiments, less than 500 micrograms, and in certain embodiments, less than 1,000 micrograms.
When delivering a pharmaceutical compound to a subject, the amount of substance that is vaporized off the surface is important. Consistency of delivery of the compound is also critical. In certain embodiments, at least 80% of the amount of material disposed on each support passes through the outlet of the device for deliver to the subject, in other embodiments, at least 90% passes through the outlet, and in other embodiments, at least 98% passes through the outlet.
In certain embodiments, a substance can comprise a pharmaceutical compound. In certain embodiments, the substance can comprise a therapeutic compound or a non-therapeutic compound. A non-therapeutic compound refers to a compound that can be used for recreational, experimental, or pre-clinical purposes. Classes of drugs that can be used include, but are not limited to, anesthetics, anticonvulsants, antidepressants, antidiabetic agents, antidotes, antiemetics, antihistamines, anti-infective agents, antineoplastics, antiparkinsonian drugs, antirheumatic agents, antipsychotics, anxiolytics, appetite stimulants and suppressants, blood modifiers, cardiovascular agents, central nervous system stimulants, drugs for Alzheimer's disease management, drugs for cystic fibrosis management, diagnostics, dietary supplements, drugs for erectile dysfunction, gastrointestinal agents, hormones, drugs for the treatment of alcoholism, drugs for the treatment of addiction, immunosuppressives, mast cell stabilizers, migraine preparations, motion sickness products, drugs for multiple sclerosis management, muscle relaxants, nonsteroidal anti-inflammatories, opioids, other analgesics and stimulants, ophthalmic preparations, osteoporosis preparations, prostaglandins, respiratory agents, sedatives and hypnotics, skin and mucous membrane agents, smoking cessation aids, Tourette's syndrome agents, urinary tract agents, and vertigo agents.
Examples of pharmaceutical compounds include fluticasone propionate, clonidine, triazolam, albuterol, ciclesonide, fentanyl, terbutaline, flumazenil, triamcinolone acetonide, flunisolide, ropinirole, alprazolam, buprenorphine, hyoscyamine, atropine, pramipexole, bumetanide, flunitrazepam, oxymorphone, colchicine, apomorphine HCl, granisetron, pergolide, nicotine, loperamide, azatadine, naratriptan, clemastine, benztropine, ibutilide, butorphanol, fluphenazine, estradiol-17-heptanoate, zolmitriptan, metaproterenol, scopolamine, diazepam, tolterodine, estazolam, haloperidol, carbinoxamine, estradiol, hydromorphone, bromazepam, perphenazine, midazolam, methadone, frovatriptan, eletriptan, testosterone, melatonin, galanthamine, cyproheptadine, bropheniramine, and chlorpheniramine. In certain embodiments, the compound is chosen from alprazolam, buprenorphine, clonindine, fentanyl, midazolam, pramipexole, ropinirole, and triazolam. In certain embodiments, the compound is chosen from a compound for the treatment of pain. In certain embodiments, the compound for the treatment of pain is fentanyl.
In certain embodiments, a drug can further comprise substances to enhance, modulate and/or control release, aerosol formation, intrapulmonary delivery, therapeutic efficacy, therapeutic potency, stability, and the like. For example, to enhance therapeutic efficacy a drug can be co-administered with one or more active agents to increase the absorption and/or diffusion of the first drug through the pulmonary alveoli, or to inhibit degradation of the drug in the systemic circulation. In certain embodiments, a drug can be co-administered with active agents having pharmacological effects that enhance the therapeutic efficacy of the drug. In certain embodiments, a drug can comprise compounds that can be used in the treatment of one or more diseases, conditions, or disorders. In certain embodiments, a drug can comprise more than one compound for treating one disease, condition, or disorder, or for treating more than one disease, condition, or disorder.
In certain embodiments, the substance can comprise one or more pharmaceutically acceptable carriers, adjuvants, and/or excipients. Pharmaceutically acceptable refers to approved or approvable by a regulatory agency of the Federal or a state government or listed in the U.S. Pharmacopoeia or other generally recognized pharmacopoeia for use in animals, and more particularly in humans.
In general, substances useful in embodiments of the disclosure can exhibit a heat of vaporization less than about 150 kJoules/mol.
Not only can the amount of compound forming a dose be impacted by deposition of aerosol particles on the device and other supports in the device, but the amount of compound forming a dose can be reduced by degradation of the active agent during release from the support. While it will be recognized that the extent and dynamics of thermal degradation can at least in part depend on a particular compound, in certain embodiments, thermal degradation can be minimized by rapidly heating the substance to a temperature sufficient to vaporize and/or sublime the active substance. In certain embodiments, the support or heating element can be heated to a temperature of at least 250° C. in less than 500 msec, in certain embodiments, to a temperature of at least 250° C. in less than 250 msec, and in certain embodiments, to a temperature of at least 250° C. in less than 100 msec.
In certain embodiments, rapid vaporization of a layer of substance can occur with minimal thermal decomposition of the substance, to produce a condensation aerosol exhibiting high purity of the substance. For example, in certain embodiments, less than 10% of the substance is decomposed during thermal vaporization resulting in a condensation aerosol with at least 90% purity and in certain embodiments, less than 5% of the substance is decomposed during thermal vaporization resulting in a condensation aerosol with at least 95% purity, and in other embodiments, less than 2% of the substance is decomposed during thermal vaporization resulting in a condensation aerosol with at least 98% purity.
For administration of a compound, the size of the particulates of the compound comprising the aerosol can be within a range appropriate for intrapulmonary delivery. Without being limited by theory, an aerosol having a mass median aerodynamic diameter (“MMAD”) ranging from 1 μm to 3 μm, and ranging from 0.01 μm to 0.10 μm are recognized as optimal for intrapulmonary delivery of pharmaceutical compounds. Aerosols characterized by a MMAD ranging from 1 μm to 3 μm can deposit on alveoli walls through gravitational settling and can be absorbed into the systemic circulation, while aerosols characterized by a MMAD ranging from about 0.01 μm to 0.10 μm can also be deposited on the alveoli walls through diffusion. Aerosols characterized by a MMAD ranging from 0.15 μm to 1 μm are generally exhaled. Thus, in certain embodiments, aerosols produced using devices and methods of producing an aerosol can having a MMAD ranging from 0.01 μm to 5 μm, in certain embodiments, a MMAD ranging from 0.05 μm to 3 μm, in certain embodiments, a MMAD ranging from 1 μm to 3 μm and in certain embodiments, a MMAD ranging from 0.01 μm to 0.1 μm. In certain embodiments, aerosols suitable for intrapulmonary delivery of pharmaceutical compounds can further be characterized by the geometric standard deviation of the log-normal particle size distribution. In certain embodiments, aerosols produced using the devices and methods of producing an aerosol comprise a geometric standard deviation of the log-normal particle size distribution of less than 3, in certain embodiments, less than 2.5, and in certain embodiments, less than 2.
In certain embodiments, a cartridge can include a part disposed in the mouthpiece to control the airflow exiting the device. A partial section view of the cartridge cross-section of
An embodiment of a condensation aerosol delivery device is the portable electric multi-dose drug delivery systems discussed herein, and illustrated in
A functional block diagram of the electronics for an exemplary embodiment of an electric multi-dose condensation aerosol delivery device 100 is shown in
As shown in
Display 162 is an electronic display which can inform a user of the current state of the device, e.g., whether the device is in the sleep or activated mode, and the number of unused doses remaining in the cartridge. User activated switch 160 is a momentary push button switch that when depressed activates the system from the sleep mode. Power source 154 comprises three alkaline primary cells that are used to power the system including providing the power necessary to vaporize the drug disposed on metal foils 136. Switch matrix 156 can be an array of MOSFET switches under control of the microcontroller that couple power from power source 154 to the appropriate drug coated foils 136. Hardware safety lockout 158 is a redundant, software-independent system that can prevent more than one dose from being delivered at a time and/or prevent a second dose from being delivered before the end of the lockout period. Hardware safety lockout 158 provides a redundant safety mechanism in the event of software malfunction.
In certain embodiments, the device is such that the total airflow passing through the outlet ranges from 10 liters/min to 100 liters/min. In other embodiments, the total airflow passing though the outlet ranges from 20 liters/min to 90 liters/min.
In certain embodiments of the device, the airflow rate through the inlet is less than 100 L/min. In other embodiments, the airflow rate through the inlet is less than 50 liters/min. In yet other embodiments, the airflow rate through the inlet is less than 25 liters/min; and in still other embodiments, the airflow rate through the inlet is less than 10 liters/min.
It should also be evident from the various embodiments disclosed herein that many parameters can be selected and/or adjusted to provide a condensation aerosol delivery device, and in particular an electric condensation aerosol delivery device capable of delivering multiple doses of a physiologically active substance to a patient with each dose being delivered during a single inhalation. It will be appreciated that at least some of the parameters are interactive, and that the multiple parameters can be adjusted by routine optimization procedures to generate a condensation aerosol comprising a dose of a particular physiologically active substance. As discussed herein, such parameters include, but are not limited to the properties of a particular substance, e.g., heat of vaporization, the quantity of substance comprising a dose, the thickness of the layer disposed on the support, the thickness of the heating element, the ratio of the surface area of the heating element to the thermal mass of the resistive heating element, and the airflow.
Embodiments of the present disclosure can be further defined by reference to the following examples, which describe in detail certain embodiments of the present disclosure. It will be apparent to those skilled in the art that many modifications, both to materials and methods, may be practiced without departing from the scope of the present disclosure.
Electric multiple dose condensation aerosol delivery devices as shown in
The device incorporated 25 supports. The supports were fabricated from 0.0005 inch thick stainless steel foils having a surface area of 0.2 cm2 and mounted in an arched configuration to minimize distortion during heating. Fifty μg of fentanyl was deposited on the surface of each foil by spray coating from a solution comprising either isopropyl alcohol, acetone, or acetonitrile. The 50 μg layer of fentanyl was 3 μm thick. The resistance of the metal foils on which the fentanyl was deposited was 0.4Ω, the ratio of the surface area of the metal foil to the thermal mass of the heating foil was 47 cm2/J/C. Either three AAA batteries or a Hewlett Packard 6002A DC power supply were used, depending on the experiment conducted, to provided 1.7 joules of energy to the heating element to vaporize the 50 μg of fentanyl.
The size of aerosol particles can impact the therapeutic efficacy of a pharmaceutical administered by inhalation. For example, aerosols having a particle size ranging from 0.01 μm to 3 μm are considered optimal for pulmonary delivery. In addition to the dynamics of aerosols during inhalation, it can be important that a condensation aerosol delivery device generate a consistent and reproducible particle size distribution. Aerosol particle size can be characterized by the mass median aerodynamic diameter (MMAD) of the aerosol. MMAD refers to the median of the distribution of particle sizes forming the aerosol.
Aerosol particle size distributions for condensation aerosols formed using the condensation aerosol delivery device described in Example 1 are presented in
The airflow in a condensation aerosol delivery device as described in Example 1 was adjusted and the particle size of five emitted doses measured using the Anderson impaction method. The airflow volume was increased from 4 L/min to 8 L/min to increasing the airflow velocity from 1 msec to 2 msec. In tests 1, 2, and 4, a bypass air routing part was inserted into the mouthpiece section of the cartridge (to get the total airflow up to 28.3 L/min for the Andersen impactor to function properly) such that the bypass air and the airflow containing the condensation aerosol joined just prior to entering the impactor. In test 3, however, bypass air was introduced into the outgoing airflow immediately after passing over the heating elements. The results are presented in Table 1.
The stability of fentanyl in multi-dose condensation aerosol delivery devices was determined by measuring the amount and purity of fentanyl in an emitted dose for a newly manufactured cartridge (diagonal lines), an unused cartridge that was stored at room temperature for 7 days (cross-hatch), and a cartridge that was used to emit 10 doses and then stored at room temperature for 7 days (solid). The results are presented in
Three AAA batteries provided 1.7 joules of energy to a 0.0005 inch thick stainless steel foil on which 50 μg of fentanyl was deposited. The airflow velocity was 1 msec corresponding to an airflow rate of 4 L/min. As shown in
The temperature uniformity of a foil having a thin layer of 50 μg of fentanyl was measured during heating. The results are shown in
The effects of the airflow in a cartridge on the deposition of the aerosol particles on downstream surfaces is demonstrated in
The purity and yield of emitted doses for devices as described in Example 1, except that the surface area of each support was 0.25 cm2, are presented in
This application is a continuation of U.S. patent application Ser. No. 12/474,680, entitled “Multiple Dose Condensation Aerosol Devices And Methods Of Forming Condensation Aerosols”, filed on May 29, 2009, which is a divisional of U.S. patent application Ser. No. 10/861,554, filed Jun. 3, 2004, entitled “Multiple Dose Condensation Aerosol Devices and Methods of Forming Condensation Aerosols,” now U.S. Pat. No. 7,540,286, the entire disclosures of which are hereby incorporated by reference. Any disclaimer that may have occurred during the prosecution of the above-referenced applications is hereby expressly rescinded, and reconsideration of all relevant art is respectfully requested.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10861554 | Jun 2004 | US |
| Child | 12474680 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12474680 | May 2009 | US |
| Child | 13078654 | US |
