Abstract:
A dry powder inhaler including a housing defining a chamber for receiving a dose of powdered medicament, an inhalation port in fluid communication with the chamber, at least one airflow inlet providing fluid communication between the chamber and an exterior of the housing, and a flutter element in the chamber and associated with a dose of powdered medicament. The flutter element has a tensioned distal end proximate the at least one airflow inlet and a free proximal end opposite to the distal end and downstream of the inlet. The flutter element is configured to vibrate in response to airflow through the chamber and aerosolize the dose of powdered medicament.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority of U.S. provisional application No. 61/281,189, entitled “Inhaler with a Different Mode of Flutter Operation,” filed on Nov. 12, 2009, and U.S. provisional application No. 61/293,577, entitled “Inhaler Apparatus and Method of Making and Using the Same,” filed on Jan. 8, 2010, the contents of both of which are incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention is directed generally to inhalers, for example, dry powder inhalers, and methods of delivering a medicament to a patient. More particularly, the present invention is directed to dry powder inhalers having a flutter dispersion member. 
       BACKGROUND 
       [0003]    Dry powder inhalers (“DPIs”) represent a promising alternative to pressurized meted dose inhaler (“pMDI”) devices for delivering drug aerosols without using CFC propellants. See generally, Crowder et al., 2001: an Odyssey in Inhaler Formulation and Design, Pharmaceutical Technology, pp. 99-113, July 2001; and Peart et al., New Developments in Dry Powder Inhaler Technology, American Pharmaceutical Review, Vol. 4, n, 3, pp. 37-45 (2001). Martonen et al. 2005 Respiratory Care, Smyth and Hickey American Journal of Drug Delivery, 2005. 
         [0004]    Typically, the DPIs are configured to deliver a powdered drug or drug mixture that includes an excipient and/or other ingredients. Conventionally, many DPIs have operated passively, relying on the inspiratory effort of the patient to dispense the drug provided by the powder. Unfortunately, this passive operation can lead to poor dosing uniformity since inspiratory capabilities can vary from patient to patient, and sometimes even use-to-use by the same patient, particularly if the patient is undergoing an asthmatic attack or respiratory-type ailment which tends to close the airway. 
         [0005]    Generally described, known single and multiple dose DPI devices use: (a) individual pre-measured doses, such as capsules containing the drug, which can be inserted into the device prior to dispensing; or (b) bulk powder reservoirs which are configured to administer successive quantities of the drug to the patient via a dispensing chamber which dispenses the proper dose. See generally, Prime et al., Review of Dry Powder Inhaler&#39;s, 26 Adv. Drug Delivery Rev., pp. 51-58 (1997); and Hickey et al., A new millennium for inhaler technology, 21 Pham. Tech., n. 6, pp. 116-125 (1997). 
         [0006]    In operation, DPI devices desire to administer a uniform aerosol dispersion amount in a desired physical form (such as a particulate size) of the dry powder into a patient&#39;s airway and direct it to a desired deposit site. If the patient is unable to provide sufficient respiratory effort, the extent of drug penetration, especially to the lower portion of the airway, may be impeded. This may result in premature deposit of the powder in the patient&#39;s mouth or throat. 
         [0007]    A number of obstacles can undesirably impact the performance of the 
         [0008]    DPI. For example, the small size of the inhalable particles in the dry powder drug mixture can subject them to forces of agglomeration and/or cohesion (i.e., certain types of dry powders are susceptible to agglomeration, which is typically caused by particles of the 20 drug adhering together), which can result in poor flow and non-uniform aerosol dispersion. In addition, as noted above, many dry powder formulations employ larger excipient particles to promote flow properties of the drug. However, separation of the drug from the excipient, as well as the presence of agglomeration, can require additional inspiratory effort, which, again, can negatively impact the aerosol dispersion of the powder within the air stream of the patient. Inadequate dispersions may inhibit the drug from reaching its preferred deposit/destination site and can prematurely deposit undue amounts of the drug elsewhere. 
         [0009]    Further, many dry powder inhalers can retain a significant amount of the drug within the device, which can be especially problematic over time. Typically, this problem requires that the device be disassembled and cleansed to assure that it is in proper working order. In addition, the hygroscopic nature of many of these dry powder drugs may also require that the device be cleansed and dried periodically. 
         [0010]    In recent years, dry powder inhalers (DPIs) have gained widespread use, particularly in the United States. Currently, the DPI market is estimated to be worth in excess of $4 billion. Dry powder inhalers have the added advantages of a wide range of doses that can be delivered, excellent stability of drugs in powder form (no refrigeration), ease of maintaining sterility, non-ozone depletion, and they require no press-and-breathe coordination. 
         [0011]    There is great potential for delivering a number of therapeutic compounds via the lungs (see, for example, Martonen T., Smyth H D C, Isaacs K., Burton R., “Issues in Drug Delivery: Dry Powder Inhaler Performance and Lung Deposition”: Respiratory Care. 2005, 50(9); and Smyth H D C, Hickey, A J, “Carriers in Drug Powder Delivery: Implications for Inhalation System Design,” American Journal of Drug Delivery, 2005, 3(2), 117-132). In the search for non-invasive delivery of biologics (which currently must be injected), it was realized that the large highly absorptive surface area of the lung with low metabolic drug degradation, could be used for systemic delivery of proteins such as insulin. The administration of small molecular weight drugs previously administered by injection is currently under investigation via the inhalation route either to provide non-invasive rapid onset of action, or to improve the therapeutic ratio for drugs acting in the lung (e.g. lung cancer). Gene therapy of pulmonary disease is still in its infancy but could provide valuable solutions to currently unmet medical needs 
         [0012]    Key to all inhalation dosage forms is the need to maximize the “respirable dose” (particles with aerodynamic diameters &lt;5.0 μm that deposit in the lung) of a therapeutic agent and reduce variability in dosing. However, both propellant-based inhalers and current DPI systems only achieve lung deposition efficiencies of less than 30% of the delivered dose. The primary reason why powder systems have limited efficiency is the difficult balancing of particle size (particles under 5 μm diameter) and strong inter-particulate forces that prevent deaggregation of powders (strong cohesive forces begin to dominate at particle sizes &lt;10 μm) (Smyth H D C., Hickey, A J., “Carriers in Drug Powder Delivery: Implications for inhalation System Design,” American Journal of Drug Delivery, 2005, 3(2), 117-132). Thus, DPIs require considerable inspiratory effort to draw the powder formulation from the device to generate aerosols for efficient lung deposition (see  FIG. 1  for an illustration of typical mechanism of powder dispersion for DPIs). Many patients, particularly asthmatic patients, children, and elderly patients, which are important patient groups for respiratory disease, are not capable of such effort. In most DPIs, approximately 60 L/min of airflow is required to effectively deaggregate the fine cohesive powder. All currently available DPIs suffer from this potential drawback. 
         [0013]    Multiple studies have shown that the dose emitted from dry powder inhalers (DPI) is dependent on air flow rates (see Martonen T., Smyth H D C, Isaccs K., Burton R., “Issues in Drug Delivery: Dry Powder Inhaler Performance and Lung Deposition”: Respiratory Care. 2005, 50(9)). Increasing air-flow increases drug dispersion due to increases in drag forces of the fluid acting on the particle located in the flow. The Turbuhaler® device (a common DPI), is not suitable for children because of the low flow achieved by this patient group (see Martonen T., Smyth H D C, Isaccs K., Burton R., “Issues in Drug Delivery: Dry Powder Inhaler Performance and Lung Deposition”: Respiratory Care. 2005, 50(9)). 
         [0014]    Considerable intra-patient variability of inhalation rates has been found when patients inhale through two conventional DPI devices. That inherent variability has prompted several companies to evaluate ways of providing energy in the inhaler (i.e. “active” DPIs). Currently, there is no active DPI commercially available. The active inhalers under investigation include technologies that use compressed air, piezoelectric actuators, and electric motors. The designs of those inhalers are very complex and utilize many moving parts and components. The complexity of those devices presents several major drawbacks including high cost, component failure risk, complex manufacturing procedures, expensive quality control, and difficulty in meeting specifications for regulatory approval and release (Food and Drug Administration). 
         [0015]    Alternatively, powder technology provides potential solutions for flow rate dependence of DPIs. For example, hollow porous microparticles having a geometric size of 5-30 μm, but aerodynamic sizes of 1-5 μm require less power for dispersion than small particles of the same mass. This may lead to flow independent drug dispersion but is likely to be limited to a few types of drugs with relevant physicochemical properties. 
         [0016]    Thus there are several problems associated with current dry powder inhaler systems including the most problematic issue: the dose a patient receives is highly dependent on the flow rate the patient can draw through the passive-dispersion device. Several patents describing potential solutions to this problem employ an external energy source to assist in the dispersion of powders and remove this dosing dependence on patient inhalation characteristics. Only one of these devices has made it to market or been approved by regulatory agencies such as the US Food and Drug Administration and has subsequently been removed from the market. Even upon approval, it is likely that these complex devices will have significant costs of manufacture and quality control, which could have a significant impact on the costs of drugs to patients. 
         [0017]    The present disclosure describes exemplary dry powder inhalers and associated single or multi-dose packaging, which holds the compound to be delivered for inhalation as a dry powder. These dry powder inhalers bridge the gap between passive devices and active devices. The inhalers are passive devices that operate using the energy generated by the patient inspiratory flow inhalation maneuver. However, the energy generated by airflow within the devices is focused on the powder by using oscillations induced by airflow across an element within the inhaler. This film or web element flutters with considerable energy and velocities to detach the drug coated on the element such that it can be aerosolized and inhaled. In this way the inhalers can be “tuned” to disperse the powder most efficiently by adjusting the resonance frequencies of the elastic element to match the physicochemical properties of the powder. In addition, the airflow rate required to generate the appropriate oscillations within the device is minimized because the energy that is harnessed by the flutter member from the inhalation flow is used to create the vibrations in the elastic element that is in direct contact with the micronized drug powder. Inhaler performance may be tailored to the lung function of individual patients by modulating the film properties, drug particle properties, and degree of coating of the particles on the film. Thus, even patients with poor lung function and those who have minimal capacity to generate airflow during inspiration will able to attain the flow rate required to induce oscillations in the flutter element. 
       SUMMARY OF THE INVENTION 
       [0018]    In accordance with various exemplary aspects of the disclosure, a dry powder inhaler may include a housing defining a chamber for receiving a dose of powdered medicament, an inhalation port in fluid communication with the chamber, at least one airflow inlet providing fluid communication between the chamber and an exterior of the housing, and a flutter element in the chamber and associated with a dose of powdered medicament. The flutter element has a tensioned distal end proximate the at least one airflow inlet and a free proximal end opposite to the distal end and downstream of the inlet. The flutter element is configured to vibrate in response to airflow through the chamber and aerosolize the dose of powdered medicament. 
         [0019]    According to various exemplary aspects, a method for delivering medicament to a patient may include tensioning a distal end of a flutter element at a distal end of a dosing chamber of a dry powder inhaler while permitting a proximal end of the flutter element to remain free of tension, exposing the flutter element, including a dose of powdered medicament, to a flow of air through the dry powder inhaler, inducing vibrations in the flutter element so as to aerosolize the dose of powdered medicament, and directing the flow of air with the aerosolized dose of powdered medicament to an outlet port of the dry powder inhaler. 
         [0020]    In some exemplary aspects, a dry powder inhaler for delivering medicament to a patient may include a housing defining a chamber and an inhalation port in fluid communication with the chamber. The inhaler may comprise a flutter element in the chamber and associated with a dose of powdered medicament. The flutter element may have a tensioned distal end proximate the at least one airflow inlet and a free proximal end opposite to the distal end and downstream of the inlet. The flutter element may be configured to vibrate in response to airflow through the chamber and aerosolize the dose of powdered medicament. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a schematic representation of a top cross-sectional view of an exemplary inhaler in accordance with various aspects of the disclosure. 
           [0022]      FIG. 2  is a schematic representation of a side cross-sectional view of the inhaler of  FIG. 1 . 
           [0023]      FIG. 3  is a schematic representation of a top cross-sectional view of an exemplary inhaler in accordance with various aspects of the disclosure. 
           [0024]      FIG. 4  is an exploded view of the inhaler of  FIG. 3 . 
           [0025]      FIG. 5  is a graph illustrating the dispersion profile of drug microparticles from a flutter element structured and arranged in accordance with exemplary apparatuses and methods of the disclosure. 
           [0026]      FIG. 6  is a graph illustrating the dispersion profile of drug microparticles from a flutter element structured and arranged in accordance with exemplary apparatuses and methods of the disclosure. 
           [0027]      FIG. 7  is a graph illustrating the dispersion profile of drug microparticles from a flutter element structured and arranged in accordance with exemplary apparatuses and methods of the disclosure. 
           [0028]      FIG. 8  is a graph illustrating the dispersion profile of drug microparticles from a flutter element structured and arranged in accordance with exemplary apparatuses and methods of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    An exemplary embodiment of a dry powder inhaler  100  is illustrated in  FIGS. 1 and 2 . According to various aspects of the disclosure, the dry powder inhaler  100  may comprise a housing  102  defining a chamber  104 . A proximal end  106  of the housing  102  may include a mouthpiece  120 . In some aspects, the mouthpiece  120  may comprise a separate structure affixed to an outer wall  112  of the housing  102 . In some aspects, the mouthpiece  120  and housing  102  may comprise a single piece of unitary construction. 
         [0030]    The mouthpiece  120  may include an opening  122  providing fluid communication between the chamber  104  and the outside of the housing  102  (i.e., ambient air). The opening  122  may be shaped as an oval, a circle, a triangle, or any other desired shape. The mouthpiece  120  may have a shape that facilitates pursing of a patient&#39;s lips over the mouthpiece  120  and creating a seal between the lips and the mouthpiece  120 . 
         [0031]    In various aspects, the inhaler  100  may include a nozzle  124  between the chamber  104  and the opening  122 . According to various aspects, the nozzle  124  may extend from the opening  122 , through the mouthpiece  120 , and into the chamber  104 . In some aspects, the nozzle  124  may comprise at least one helical tube  126  through which air and powder can be inhaled. The tube  126  can be configured to increase the turbulence in the air that flows through the nozzle  124 . According to various aspects, the mouthpiece  120  and/or the housing  102  may include a mesh, screen, or the like (not shown) to prevent undesirably large particles, such as, for example, carrier particles, from exiting the inhaler  100  and entering a user&#39;s mouth and/or airways. 
         [0032]    In accordance with various aspects, a distal end  108  of the housing  102  may include one or more airflow inlets  128  providing fluid communication between the chamber  104  and ambient air outside the housing  102 . A flutter element  140  may extend across a center region  114  of the chamber  104  at or near the inlets and at or near the wall of the distal end  108  of the housing. In some aspects, the flutter element  140  may extend between opposing inner walls  116 ,  118  of the housing  102 . According to various aspects, the airflow inlets  128  may be shaped as elongated slots, and the flutter element  140  may be arranged such that the planar surfaces of the element  140  extend substantially parallel with the longitudinal direction of the elongated slot. As such, airflow through the chamber  104  may flow above and/or below the flutter element  140  depending on whether the element  140  is positioned at the bottom of the slot, the middle of the slot, or the top of the slot. 
         [0033]    The flutter element  140  may be pre-coated with a dose of a medicament, for example, a dose of powdered medicament, and the center region  114  may comprise a region for dispensing a dose of medicament into airflow through the inhaler  100 . In some aspects, the powdered particles are tightly bound to the element  140  such that the particles remain substantially on the element  140  until used for an inhalation dose. Contact of the coated element  140  with surfaces of the inhaler assembly and/or packaging should not impact the dosage. 
         [0034]    The term “medicament” as used throughout this disclosure may include one or more drugs and/or compositions for treatment. For example, the flutter element  140  may be coated with a medicament containing two or more drug mixed together. In some aspects, two or more drugs may be coated onto the element  140  in a side-by-side manner or any other pattern. In some aspects, the chamber  104  may be divided into compartments, and each compartment may contain a separate flutter element  140  with the same or different medicament and/or drug(s) coated thereon. In some aspects, the chamber  104  may be divided into compartments, and each compartment may contain a portion of the same flutter element  140 , with each portion having the same or different medicament and/or drug(s) coated thereon. 
         [0035]    According to some aspects, the flutter element  140  may comprise a membrane  142 , for example, a thin elastic membrane, and in some aspects an aeroelastic membrane. In accordance with some aspects, the flutter element  140  may comprise a membrane, a film, a reed, a sheet, a panel, or a blade. The flutter element  140  may be manufactured of materials comprising polymers, thin metals, and/or metal-coated polymers. In some aspects, the element  140  may be inserted into the inhaler  100 , used, and then discarded. In some aspects, the entire inhaler may be disposed of after a single use. It should be appreciated that the flutter element  140  can be made thicker and/or more rigid to reduce the degree to which the element  140  will droop in the absence of airflow due to the force of gravity. A more rigid and/or thicker element  140  may result in less flutter insofar as amplitude and wavelength, but at a higher frequency. 
         [0036]    According to various aspects, a first end  144  of the element  140  is proximate the airflow inlet  128  at the distal end  108  of the housing  102 . The first end  144  of the element  140  is held substantially taught across the chamber  104 . A second end  146  of the element  140 , opposite to the first end  144 , is left free as it extends towards the proximal end  106  of the housing  102 . Thus, the element  140  is free to flutter, for example, like a flag, as air flows through the chamber  104  from the airflow inlet  128  to the mouthpiece  120 . 
         [0037]    It should be appreciated that the first end  144  of the element  140  may be held by any known structure and method. For example, the element  140  may be coupled to the housing  102  in tension via clipping, gluing, adhering, bonding, molding, fusing, or the like. In some aspects, the housing  102  may comprise top and bottom shells (not shown), and the first end  144  of the element  140  may be sandwiched between the shells in a substantially taught configuration, while the second end  146  is left free to flutter in airflow or droop in the absence of airflow. It would be understood by a person skilled in the art that the amount of droop would depend on the material and composition of the element  140 . 
         [0038]    The tensioning of a leading end of the element (with respect to airflow direction) while leaving the opposite end free may provide performance increases over a fully-tensioned element due to improved energy transfer into the powder coating the film. For example, velocity differentials of airflow over the film will generate pressure changes which curve the flow and set up vortices. As these vortices propagate along the length of the film, they generate centrifugal forces which induce tension in the film; and this tension opposes and ultimately limits the amplitudes of the film flutter. Thus when air flows over the flexible film with induced tension, there is a dynamics of lift forces normal to the film surface and an opposing drag force due to the tensioned edge. 
         [0039]    Referring now to  FIGS. 3 and 4 , according to various aspects, an exemplary inhaler assembly  300  may include a first housing  302  and a second housing  350 . The first housing  302  defines a chamber  304 . A proximal end  306  of the housing  302  may include a mouthpiece  320 . In some aspects, the mouthpiece  320  may comprise a separate structure affixed to an outer wall  312  of the housing  302 . In some aspects, the mouthpiece  320  and housing  302  may comprise a single piece of unitary construction. 
         [0040]    The mouthpiece  320  may include an opening  322  providing fluid communication between the chamber  304  and the outside of the housing  302  (i.e., ambient air). The opening  322  may be shaped as an oval, a circle, a triangle, or any other desired shape. The mouthpiece  320  may have a shape that facilitates pursing of a patient&#39;s lips over the mouthpiece  320  and creating a seal between the lips and the mouthpiece  320 . 
         [0041]    In various aspects, the inhaler  300  may include a nozzle  324  between the chamber  304  and the opening  322 . According to various aspects, the nozzle  324  may extend from the opening  322 , through the mouthpiece  320 , and into the chamber  304 . In some aspects, the nozzle  324  may comprise at least one helical tube  326  through which air and powder can be inhaled. The tube  326  can be configured to increase the turbulence in the air that flows through the nozzle  324 . According to various aspects, the mouthpiece  320  and/or the housing  302  may include a mesh, screen, or the like (not shown) to prevent undesirably large particles, such as, for example, carrier particles, from exiting the inhaler assembly  300  and entering a user&#39;s mouth and/or airways. 
         [0042]    In accordance with various aspects, a distal end  308  of the housing  302  may include an opening  310  and a coupling mechanism  330 . The coupling mechanism  330  may comprise any known structure for coupling two housings to one another, such as, for example, a snap fit, a friction/interference fit, a screw fit, and the like. 
         [0043]    The second housing  350  defines a chamber  352  having an open proximal end  362 . The proximal end  362  of the second housing  350  may include a coupling mechanism  360  structured and arranged to cooperate with the coupling mechanism  330  of the first housing  302  to couple the first and second housings  302 ,  350  to one another. When the first and second housings  302 ,  350  are coupled together, the chambers  304 ,  352  are in fluid communication with one another. A distal end  364  of the second housing  350  may include one or more airflow inlets  328  providing fluid communication between a chamber  352  and ambient air outside the housing  350 . 
         [0044]    A flutter element  340  may extend across a center region  354  of the chamber  352  at or near the inlets and at or near the wall of the distal end  364  of the housing  350 . In some aspects, the flutter element  340  may extend between opposing inner walls  356 ,  358  of the second housing  350 . According to various aspects, the airflow inlets  328  may be shaped as elongated slots, and the flutter element  340  may be arranged such that the planar surfaces of the element  340  extend substantially parallel with the longitudinal direction of the elongated slot. As such, airflow through the chamber  352  may flow above and/or below the flutter element  340  depending on whether the element  340  is positioned at the bottom of the slot, the middle of the slot, or the top of the slot. 
         [0045]    The flutter element  340  may be pre-coated with a dose of a medicament, for example, a dose of powdered medicament, and the chamber  352  of the second housing  350  may comprise a region for dispensing a dose of medicament into airflow through the inhaler assembly  300 . The flutter element  340  may be pre-coated with a dose of a medicament, for example, a dose of powdered medicament, and the chamber  352  may comprise a region for dispensing a dose of medicament into airflow through the inhaler assembly  300 . In some aspects, the powdered particles are tightly bound to the element  340  such that the particles remain substantially on the element  340  until used for an inhalation dose. Contact of the coated element  340  with surfaces of the inhaler assembly and/or packaging should not impact the dosage. 
         [0046]    The term “medicament” as used throughout this disclosure may include one or more drugs and/or compositions for treatment. For example, the flutter element  340  may be coated with a medicament containing two or more drug mixed together. In some aspects, two or more drugs may be coated onto the element  340  in a side-by-side manner or any other pattern. In some aspects, the chamber  352  may be divided into compartments, and each compartment may contain a separate flutter element  340  with the same or different medicament and/or drug(s) coated thereon. In some aspects, the chamber  352  may be divided into compartments, and each compartment may contain a portion of the same flutter element  340 , with each portion having the same or different medicament and/or drug(s) coated thereon. 
         [0047]    According to some aspects, the flutter element  340  may comprise a membrane  342 , for example, a thin elastic membrane. In accordance with some aspects, the flutter element  340  may comprise a membrane, a film, a reed, a sheet, a panel, or a blade. The flutter element may be manufactured of materials comprising polymers, thin metals, and/or metal-coated polymers. It should be appreciated that the flutter element  340  can be made thicker and/or more rigid to reduce the degree to which the element  340  will droop in the absence of airflow due to the force of gravity. A more rigid and/or thicker element  340  may result in less flutter insofar as amplitude and wavelength, but at a higher frequency. 
         [0048]    According to various aspects, a first end  344  of the element  340  is proximate the airflow inlet  328  at the distal end  364  of the second housing  350 . The first end  344  of the element  340  is held substantially taught across the chamber  352 . A second end  346  of the element  340 , opposite to the first end  344 , is left free as it extends towards the proximal end  306  of the first housing  302 . Thus, the element  340  is free to flutter, for example, like a flag, as air flows through the chamber  352  from the airflow inlet  328  to the chamber  304  of the first housing  302  and eventually to the mouthpiece  320 . 
         [0049]    It should be appreciated that the first end  344  of the element  340  may be held by any known structure and method. For example, the element  340  may be coupled to the second housing  350  in tension via clipping, gluing, adhering, bonding, molding, fusing, or the like. In some aspects, as shown in  FIG. 4 , the second housing  350  may comprise a first housing member  372  and a second housing member  374  structured to be coupled together in any known manner, such as for example, a snap fit, or friction/interference fit relationship. One skilled in the art would recognize that an element  340  pre-coated with a dose of dry powder medicament can be press-fit between the first and second housing members  372 ,  374  when they are coupled together to hold the first end  344  of the element  340  in a substantially taught configuration, while the second end  346  is left free to flutter in airflow or droop in the absence of airflow. 
         [0050]    It should be appreciated that the second housing  350  of the inhaler assembly  300  may comprise a single powder dose such that the second housing  350  may be decoupled from the first housing  302  and disposed of after a single use, while the first housing  302  may be reusable. In some aspects, the second housing  350  may include multiple compartments, each containing a separate flutter element  340  or a portion of the same flutter element  340 , and the flutter element in each compartment may be coated with the same or different drugs and/or medicament. A new second housing containing a single powder dose may be packaged to maintain the dose in a sterile condition according to government regulations. When another dose is to be dispensed, a user removes the new second housing from the packaging and attaches the new second housing to the first housing  302  for use. 
         [0051]    It should also be appreciated that the flutter element  140 ,  340 , in some aspects, may be wrapped on a spool. The flutter element may be coated with one or more drugs and/or medicament in any manner. An inhaler in accordance with such aspects may include a delivery spool and a take-up spool working in cooperation with a mechanical and/or electrical drive system for moving a coated region of the flutter element into position for dispersal into the airflow through the inhaler, as would be understood by persons skilled in the art. Inhalers according to such aspects may further include a cutting member for removing the tension at a proximal end of the flutter element so that the inhaler may operate similar to the previously described embodiments. 
         [0052]    In operation, a method for dispensing powder by inhalation using any of the aforementioned exemplary dry powder inhaler apparatuses may begin with a patient pursing his/her lips around the mouthpiece and inhaling. As the patient inhales, air is sucked into the inhaler through one or more airflow inlets at the distal end of the inhaler. The inhaled air flows over the flutter element causing the element to flutter. The vibration or flutter of the element disperses a dose of powdered medicament from the element into the airflow. The combined flow of air and powder then flow into the distal end of the airflow nozzle and the mouthpiece. The combined flow of air and powder leave the mouthpiece and enter the patient&#39;s mouth and respiratory tract. The airflow modifiers and/or the helical shape of the nozzle may increase the turbulence of the airflow to better aerosolize and break up the powdered dose of medicament into smaller particles, thus maximizing the dose received by the patient and allowing the smaller particles to pass further into the respiratory tract. 
       EXAMPLE 1 
     Effect of Flow Rate 
       [0053]    The aerosol properties of the prototype are determined by a Next Generation Impactor (NGI). The device geometry used in this first example is a truncated cone-single barrel (TC-SB) with inlet diameter of 0.4 cm and outlet diameter of 0.6 mm and length of 2.5 cm. The film (i.e., flutter membrane) is a polyolefin film (length=2.8 cm, width=0.3 cm, and a thickness of 85 microns). The flow rates studied are 30 lpm and 60 lpm. The drug used here is ciprofloxacin and is analyzed analytically using a UVvis spectrophotometer. 
         [0054]    As shown in  FIG. 5 , more drug is removed from the film at 60 lpm than 30 lpm. The respirable fraction (RF) at 60 lpm is 56.75±2.73% compared to that of 30 lpm which is 46.62±6.34%. The fine particle fraction (FPF) at 60 lpm and 30 lpm is statistically similar at 65.06±6.84% and 60.65±7.64%. 
       EXAMPLE 2 
     Effect of Device Geometry 
       [0055]    The device geometry may play an important role in drug dispersion. 
         [0056]    The device geometries used in this example is a truncated cone-singe barrel (TC-SB), truncated cone-double barrel (TC-DB, made of two single barrel), cylindrical chamber (CC, diameter of=0.6 cm and length=2.5 cm), Slit nozzle (SN, rectangular nozzle—3cm by 1 mm). The drug used here is ciprofloxacin and is analyzed analytically using a UVvis spectrophotometer. The flow rate is 60 lpm. 
         [0057]    As shown in  FIG. 6 , more drug is removed from the film in TC-single barrel than double barrel. However there is more throat deposition in TC-single barrel. The Cylindrical chamber has most drug removed from the film. This suggests the magnitude of dynamic flutter forces is lowest in cylindrical chamber. More device deposition is noticed in slit nozzle. The FPF and RF are shown for the following devices are shown in the table below. 
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 FPF and RF percentages for various device geometries. 
               
             
          
           
               
                   
                 Device 
                 FPF (%) 
                 RF (%) 
               
               
                   
                   
               
               
                   
                 Truncated Cone-SB 
                 65.06 ± 6.84 
                 56.75 ± 2.73 
               
               
                   
                 Truncated Cone-DB 
                 57.65 ± 2.91 
                 36.53 ± 1.78 
               
               
                   
                 Cylindrical Chamber 
                 59.91 ± 2.05 
                 34.49 ± 2.49 
               
               
                   
                 Slit Nozzle 
                 72.73 ± 3.63 
                 52.26 ± 2.61 
               
               
                   
                   
               
             
          
         
       
     
       EXAMPLE 3  
     Effect of Field Dimensions (Length) 
       [0058]    In the slit nozzle device, the effect of film length is studied. The two lengths that are studied are 3 cm and 1.5 cm. The drug used here is ciprofloxacin and is analyzed analytically using UVvis spectrophotometer. The flow rate is 60 lpm. 
         [0059]    As shown in  FIG. 7 , as the length is increased, drug removal from the film is decreased and a higher percentage drug is deposited in the throat. RF is higher when we use a 1.5 cm film compared to that of 3 cm length, as shown in the table below. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 FPF and RF percentages for various film lengths. 
               
             
          
           
               
                 Length of film 
                 FPF (%) 
                 RF (%) 
               
               
                   
               
               
                 1.5 cm 
                 72.73 ± 3.63 
                 52.26 ± 2.61 
               
               
                   3 cm 
                 67.14 ± 3.36 
                 34.38 ± 1.72 
               
               
                   
               
             
          
         
       
     
       EXAMPLE 4 
     Effect of Field Dimensions (Film Thickness) 
       [0060]    In the slit nozzle device, the effect of film thickness is studied. The two thicknesses that are studied are 0.085 mm and 0.150 mm. The drug used here is ciprofloxacin and is analyzed analytically using a UVvis spectrophotometer. The flow rate is 60 lpm. 
         [0061]    As shown in  FIG. 8 , the percentage of drug remaining in the film is higher for the thicker film. This suggests that the film is more rigid at higher thickness resulting in lower magnitude flutter forces at the same flow rate, as supported by Table 3 below. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 FPF and RF percentages for various film thicknesses. 
               
             
          
           
               
                 Thickness of film 
                 FPF (%) 
                 RF (%) 
               
               
                   
               
               
                 0.085 mm 
                 65.06 ± 6.84 
                 56.76 ± 2.74 
               
               
                  0.15 mm 
                 64.79 ± 4.86 
                 48.14 ± 3.61 
               
               
                   
               
             
          
         
       
     
       EXAMPLE 5 
       [0062]    Various critical dimensions of the design illustrated in  FIG. 4  were assessed for their effect on device performance (Table 1a). The device was manufactured using normal resolution stereo lithography in 0.004-inch layers and post-processed for biocompatibility for passing USP class VI testing. The device was manufactured out of a biocompatible, low viscosity photopolymer. The aerosol dispersion characteristics of the prototype have been determined using the Next Generation Impactor (NGI). The flow rate of operation was 60 lpm. The film used in these studies was a 0.085 mm polyolefin film (MPF, Dow Chemicals ltd.). The model drug used in the study was ciprofloxacin and was analyzed analytically using UV-vis spectrophotometer at 280 nm. 
         [0063]    Parameters determined: The following parameters were determined from the NGI dispersion data: (1) Fine Particle Fraction (FPF)—the percentage of drug deposition from stages 3 to 8 with respect to total emitted dose (throat to stage 8). (2) Fine Particle Dose (FPD)—the amount of drug deposited in stage 3 to stage 8. (3) Respirable Fraction (RF)—the percentage of drug deposition in stages 3 to 8 with respect to the total dosage. (4) Mean Mass Aerodynamic Diameter (MMAD). 
         [0064]    Table 4a details the aerosol properties of the prototypes as the depth and angle of opening (q) of the prototype are varied at a constant length. At a constant length, the aerosol performance changes significantly with depth. As shown in  FIG. 9 , the FPF decrease by approximately  15 % as the inlet depth of the prototype is doubled. The performance of the device (FPF and RF) decreases by a modest 5% as the angle of inlet is doubled. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 4a 
               
             
             
               
                   
               
               
                 Aerosol Properties as a function of dimension @ constant length (L). 
               
             
          
           
               
                 Depth 
                 Length 
                 Angle 
                   
                   
                   
                 MMAD 
               
               
                 (D, mm) 
                 (L, mm) 
                 (θ) 
                 FPF (%) 
                 RF (%) 
                 FPD (mcg) 
                 (mm) 
               
               
                   
               
             
          
           
               
                 1 
                 40 
                 5.75 
                 50.42 ± 1.48 
                 40.90 ± 1.89 
                 471.73 ± 3.58  
                 2.86 ± 0.02 
               
               
                 2 
                 40 
                 5.75 
                 34.57 ± 1.21 
                 24.84 ± 1.82 
                 310.23 ± 13.78 
                 3.37 ± 0.11 
               
               
                 1 
                 40 
                 11.5 
                 45.67 ± 3.01 
                 36.24 ± 2.55 
                  384.2 ± 30.65 
                 3.29 ± 0.2  
               
               
                 2 
                 40 
                 11.5 
                 28.24 ± 0.83 
                  20.2 ± 0.84 
                 294.52 ± 23.43 
                 3.72 ± 0.11 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 4b 
               
             
             
               
                   
               
               
                 Aerosol Properties as a function of dimension@ constant angle (q). 
               
             
          
           
               
                 Depth 
                 Length 
                 Angle 
                   
                   
                   
                 MMAD 
               
               
                 (D, mm) 
                 (L, mm) 
                 (θ) 
                 FPF (%) 
                 RF (%) 
                 FPD (mcg) 
                 (mm) 
               
               
                   
               
             
          
           
               
                 1 
                 40 
                 5.75 
                 58.21 ± 3.65 
                 47.56 ± 4.42 
                 503.24 ± 43.77 
                 2.48 ± 0.04 
               
               
                 2 
                 40 
                 5.75 
                 38.21 ± 3.61 
                 27.65 ± 4.36 
                 323.91 ± 25.37 
                 2.98 ± 0.04 
               
               
                 1 
                 20 
                 5.75 
                 49.87 ± 1.12 
                 41.71 ± 1.77 
                 545.64 ± 114.9 
                 2.81 ± 0.13 
               
               
                 2 
                 20 
                 5.75 
                 35.72 ± 3.13 
                 25.68 ± 1.71 
                 288.07 ± 16.40 
                 3.15 ± 0.02 
               
               
                   
               
             
          
         
       
     
         [0065]    Table 4b details the aerosol properties of the prototypes as the depth and length of the prototype are varied at a constant angle of opening. At a constant angle of opening (q), the aerosol performance is significantly affected by both the depth (D) as well as the length of the prototype. An increase in depth results in decrease in aerosol performance and an increase in length results in the increase of aerosol performance. 
         [0066]    The effect of loaded dose on the film on the aerosol dispersion is further noted in Table 5. The two different amounts of loaded dose on the prototype (length—40 mm, depth—1 mm and q—5.75°) were 5647.12±437.88 mg (high dosage) and 1058.62±21.61 mg (low dosage). For the higher loaded dose, there was a significantly higher deposition of drug in the throat, pre-separator, stage 1 and lower deposition in the final three stages. This is due to the fact drug particles were dispersed as agglomerates resulting in increased deposition in the throat, pre-separator area. A FPD of approximately 2350 mg could be delivered using the high loaded dose. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Aerosol Properties as a function of dosage. 
               
             
          
           
               
                   
                 Low dosage 
                 High Dosage 
               
               
                   
                   
               
             
          
           
               
                   
                 FPF (%) 
                 58.20 ± 3.65 
                 46.54 ± 3.65 
               
               
                   
                 RF (%) 
                 47.56 ± 4.42 
                 40.49 ± 4.42 
               
               
                   
                 FPD (mg) 
                 610.65 ± 40.92 
                 2354.66 ± 330.56 
               
               
                   
                   
               
             
          
         
       
     
         [0067]    The flutter based model prototype was capable of producing significant aerosol dispersion of nearly 58% FPF and 47.5% RF. The performance of the device could be optimized by the manipulation of the dimensions of the prototype. A maximum fine particle dose (FPD) of up to 2350 mg of drug using high dosage films was achieved. 
         [0068]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular terms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
         [0069]    It will be apparent to those skilled in the art that various modifications and variations can be made in the inhalers and methods of the present disclosure without departing from the scope of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only.