Patent Publication Number: US-2022218926-A1

Title: Inhaler and method of detecting obstruction

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to inhalation devices and, more particularly, to detecting an obstruction of an air inlet of inhalation devices and a method of detecting the obstruction. 
     BACKGROUND 
     For various reasons, a certain percentage of patients suffering from chronic illnesses, such as asthma and chronic obstructive pulmonary disease (COPD), do not take their prescription as described. This can inhibit patient improvement and cause disease progression. Hence, adherence programs can be used to measure an extent to which patients follow their prescribed medication for treatment of their health condition. 
     Inhalers for pulmonary delivery, whether they be press-and-breathe or breath-actuated type devices, can deliver a medicament to an oral cavity of a patient. The medicament is delivered through an orifice which is in fluid communication with a fluid source, such as a canister. 
     Press-and-breathe and breath-actuated inhalers often include an air inlet that allows an inflow of air into the inhaler such that the medicament released from a reservoir or a canister enters this air flow. It is important not to obstruct the air inlet when administering the medicament. Obstruction of the air inlet whilst administering the medicament can reduce the operational effectiveness of an inhaler. A certain percentage of users knowingly or unknowingly obstruct the air inlet. 
     SUMMARY 
     In one aspect, the present disclosure relates to an inhaler for delivering a medicament to a patient. The inhaler includes an actuator housing for holding the medicament. The actuator housing includes an air inlet for receiving air flow. The actuator housing further defines an air flow path into which the medicament is dispensed. The inhaler also includes a sensor. The sensor is configured to detect an obstruction of the air inlet and to generate an output signal indicative of the obstruction. The inhaler further includes a feedback device configured to receive the output signal from the sensor and to generate a feedback signal that indicates obstruction of the air inlet. 
     In another aspect, the present disclosure relates to a method of detecting an obstruction of an air inlet of an inhaler. The inhaler is used for delivering a medicament to a patient. The method includes detecting the obstruction of the air inlet by a sensor. The method includes generating an output signal indicative of the obstruction by the sensor. The method includes receiving the output signal from the sensor at a feedback device. The method includes generating a feedback signal by the feedback device indicating obstruction of the air inlet. 
     In another aspect, the present disclosure relates to an inhaler for delivering a medicament to a patient. The inhaler includes an actuator housing for holding the medicament. The actuator housing includes an air inlet for receiving air flow. The actuator housing further defines an air flow path into which the medicament is dispensed. The inhaler also includes an add-on device detachably connected to the actuator housing. The add-on device includes a sensor. The sensor is configured to detect an obstruction of the air inlet and to generate an output signal indicative of the obstruction. The add-on device also includes a feedback device configured to receive the output signal from the sensor and to generate a feedback signal. The feedback signal indicates obstruction of the air inlet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments disclosed herein may be more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number. 
         FIG. 1  is a perspective view of an inhaler according to embodiments of the present disclosure; 
         FIG. 2  is a perspective view of an air inlet cover associated with the inhaler depicted in  FIG. 1 ; 
         FIG. 3  is a schematic representation of the inhaler depicted in  FIG. 1  having a sensor disposed on an actuator housing of the inhaler according to embodiments of the present disclosure; 
         FIG. 4  is a block diagram illustrating a system associated with the inhaler depicted in  FIG. 1  for detecting an obstruction of an air inlet of the inhaler according to embodiments of the present disclosure; 
         FIG. 5  is a schematic representation of the inhaler depicted in  FIG. 1  having the sensor disposed obliquely on the actuator housing of the inhaler according to embodiments of the present disclosure; 
         FIG. 6  is a schematic representation of an inhaler having the sensor disposed on an add-on device associated with the inhaler according to embodiments of the present disclosure; 
         FIG. 7  is a schematic representation of an inhaler having a sensor mounted at a bottom portion of the add-on device associated with the inhaler according to embodiments of the present disclosure; 
         FIG. 8  is a schematic representation of the inhaler depicted in  FIG. 1  having the sensor mounted in an air flow path defined by the actuator housing according to embodiments of the present disclosure; 
         FIG. 9A  is a schematic representation of an inhaler having a sensor disposed generally parallel to an air flow path defined by an actuator housing and a cover member of the inhaler in an open position according to embodiments of the present disclosure; 
         FIG. 9B  is a schematic representation of the inhaler depicted in  FIG. 9A  illustrating the cover member of the inhaler in a closed position according to embodiments of the present disclosure; 
         FIG. 10A  is a schematic representation of an inhaler having a sensor disposed generally parallel to an air flow path defined by an actuator housing and a cover member of the inhaler in an open position according to embodiments of the present disclosure; 
         FIG. 10B  is a schematic representation of the inhaler depicted in  FIG. 10A  illustrating the cover member of the inhaler in a closed position according to embodiments of the present disclosure; 
       and 
         FIG. 11  is a flowchart for a method of detecting the obstruction of the air inlet of the inhaler. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are depicted by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. 
     The present disclosure will be described with respect to particular embodiments and with reference to certain drawings, but the disclosure is not limited thereto. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may for illustrative purposes be exaggerated and not drawn to scale. 
     It will be understood that the terms “vertical”, “horizontal”, “top”, “bottom”, “above”, “below”, “left”, “right” etc. as used herein refer to particular orientations of the figures and these terms are not limitations to the specific embodiments described herein. 
     Common inhalers include pressurized metered-dose inhalers (pMDIs), dry powder inhalers (DPIs), and soft mist inhalers (SMIs), all of which have drug reservoirs and airflow paths extending from an air inlet to an air outlet. Examples of inhalers are described in International Patent Application Publications WO 2017/112400 and WO2015/034709, which are incorporated herein by reference in their entirety. Although subsequent description is for specific embodiments of pMDIs, the present disclosure can be applicable to all types of inhalers. In embodiments, a pMDI comprises a canister-retaining or tubular housing portion and a tubular mouthpiece portion, the tubular mouthpiece portion being angled with respect to the tubular housing portion. An air inlet is defined at an upper end and/or a lower end of the tubular housing portion. Proximal to the lower end of the tubular housing portion, a thumb grip is provided. Further, a metering valve is disposed within the tubular housing portion that releases a metered amount of medicament from a canister or reservoir of the inhaler. In operation of the inhaler, a plume of medicament produced from an orifice that is in communication with the metering valve is introduced into the tubular mouthpiece portion and is inhaled by a patient through the tubular mouthpiece portion. However, as described above, there can sometimes be an undesirable obstruction at the air inlet of the inhaler. 
       FIG. 1  illustrates a perspective view of an inhaler  100  for delivering a medicament to a patient. The inhaler  100  may be embodied as an electronic inhaler. Further, the inhaler  100  may include an onboard power source (not depicted), such as batteries or cells, that powers various electronic components of the inhaler  100  (including the sensors, receivers, and feedback devices described below). In an embodiment, the inhaler  100  is a press-and-breathe inhaler. Such a press-and-breathe inhaler includes a housing and a mouthpiece defined at a lower section of the housing. Further, the housing receives a canister having a generally cylindrical structure and a metering valve. The canister releases a spray of medicament when the canister is depressed by the patient. In such inhalers, the spray may be introduced directly into the patient&#39;s mouth, nasal area, or respiratory airways. Such devices can be actuated by pressure applied by the patient&#39;s fingers, button action, or other related manual techniques. 
     In another embodiment, the inhaler  100  is a breath-actuated inhaler. In such a case, the metering valve may be actuated by a pressure differential created by inhalation of a patient to automatically dispense a spray of the medicament without any manual intervention. In some embodiments, the inhaler  100  may have to be primed by the patient before breath-actuated inhalation. The inhaler  100  may be primed by moving a priming actuator, such as a lever or a mouthpiece cover. The inhaler  100  includes an actuator housing  102  for holding the medicament. The actuator housing  102  defines an air flow path “F” into which the medicament is dispensed. The air flow path “F” may be defined as a flow path that an air flow follows while flowing through the inhaler  100 . The actuator housing  102  includes a housing portion  108 . The housing portion  108  has a substantially hollow structure and is tubular in shape. 
     A canister (not depicted) is removably received within the housing portion  108 . The canister contains a fluid formulated with the medicament and is embodied as an aerosol canister. In another embodiment, the fluid formulated with the medicament may be stored in a reservoir. The canister may have a generally cylindrical structure. The canister includes a metering valve (not depicted) for metering an amount of the medicament exiting the canister corresponding to a single spray pattern or spray plume. The canister releases a predetermined amount of the medicament through the metering valve upon actuation. The canister further includes a valve stem (not depicted) extending from the metering valve. At a closed bottom end of the actuator housing  102  sits a nozzle block (not depicted) that includes a stem socket (not depicted). The stem socket is provided for receiving the valve stem of the canister. The stem socket includes an exit orifice (not depicted) or actuator nozzle (not depicted) communicating with the mouthpiece  106  of the inhaler  100 . 
     The actuator housing  102  defines an outer surface  122 . The outer surface  122  has a grip section (not depicted). The grip section is can be proximate to the bottom end of the actuator housing  102 . The grip section allows a user to hold the inhaler  100  during use. The grip section may optionally include a set of protrusions, a set of indents, or a sleeve to provide an enhanced gripping surface. The actuator housing  102  can optionally include a display device  136  for providing notifications to the patient. For example, the display device  136  may notify the patient when the medicament in the canister is about to deplete. 
     Further, the actuator housing  102  includes an air inlet  104  for receiving the air flow. The air inlet  104  is defined at an upper end of the actuator housing  102 . In alternative embodiments, the air inlet  104  is defined at a lower end of the actuator housing  102 . The actuator housing  102  can include an air inlet cover  116  that at least partially outlines one or more openings of the air inlet  104 . The air inlet cover  116  may be embodied as a grille. As depicted in the illustrated embodiment of  FIG. 2 , the air inlet cover  116  can have several apertures  120  that allow the air flow to enter the inhaler  100 . The air inlet cover  116  is generally semi-circular in shape in the illustrated embodiment. It should be understood, however, that the air inlet cover is not limited to this shape and can be other shapes in other embodiments. In the illustrated embodiment, the apertures  120  have a generally circular shape. However, in other embodiments, the apertures  120  may have any other non-circular shape, for example, polygonal, elliptical, rectangular and so forth. In various examples, a diameter of the apertures  120  may vary across the air inlet cover  116 . Further, the actuator housing  102  also defines a wall  134  (depicted in  FIG. 3 ), such that in the illustrated embodiment the air inlet  104  is defined by the wall  134  and the air inlet cover  116 . In other embodiments, the air inlet  104  is defined by the wall  134  and the air inlet cover  116  is optional. 
     The air inlet can be an opening in the actuator housing of any shape or size that provides for the required air flow to the device and is not necessarily limited to any specific position in the housing. The air inlet can be a simple uncovered opening in the housing or it can contain a cover. 
     In embodiments with an air inlet cover, the air inlet cover at least partially covers the air inlet. The air inlet cover can help to direct airflow and to partially limit the ingress of contaminants such as dust, dirt, liquids, and other environmental debris into the internal portion of the inhaler. The cover portion of the air inlet can have openings to allow for the inflow of air. For example, the air inlet cover may be in the form of a screen, grille, vents, a plate with one or more apertures, or a plate with elongated slots. The air inlet cover may be a separate part affixed to the actuator or may be integrated into the housing. For example, the housing can be made as a molded plastic part and the cover of the air inlet (such as a screen or grille) is incorporated as part of the molded housing. Referring to  FIG. 1 , the mouthpiece is embodied as a generally tubular portion extending from the actuator housing  102 . The mouthpiece  106  is joined to the housing portion  108 . In an example, the mouthpiece  106  is angled with respect to the actuator housing  102 . The mouthpiece  106  may have a circular cross-section or a non-circular cross-section, such as an elliptical or oblong cross-section. Further, the mouthpiece  106  has a substantially hollow structure. 
     The mouthpiece  106  defines a mouthpiece end  130  (depicted  FIG. 3 ). A user or the patient may put at least a part of the mouthpiece end  130  into his mouth for using the inhaler  100 . The mouthpiece end  130  may include a cross-section perpendicular to an axis of flow “S”. The axis of flow “S” may be defined a general direction in which a spray of metered medicament is dispensed through the mouthpiece  106 . The shape of the mouthpiece end  130  may include any suitable shape such as circular, a substantially oval shape, a substantially elliptical shape, or a polygonal shape. The present disclosure is not limited by the shape of the cross-section of the mouthpiece end  130 . 
     The mouthpiece  106  may be provided with a dust cap  132 . In one example, the dust cap  132  is pivotable between a closed position and an open position. In use, the patient may rotate the dust cap  132  to its open position and insert the exposed mouthpiece  106  into their mouth. Alternatively, the dust cap  132  can be detached from the inhaler to use the inhaler  100  and may be reattached after using the inhaler  100 . 
     When the inhaler  100  is a breath actuated inhaler design, inhalation by the patient through the mouthpiece  106 , produces a pressure differential in the actuator housing  102  that causes the breath-actuated mechanism to automatically displace the canister relative to the valve stem. The medicament contained within the metering chamber of the canister is accordingly released in response to the patient&#39;s inspiration. 
     During the patient&#39;s inspiration, air flows from the air inlet  104 , through the actuator housing  102 , to the mouthpiece  106 , and then to the patient. The medicament released from the metering chamber of the canister enters this air flow. Thus, during operation of the inhaler  100 , a plume of the medicament produced from the exit orifice or the actuator nozzle is inhaled by the patient through the mouthpiece  106 . After inhalation of a dose of the medicament by the patient, the dust cap  132  can be returned to its closed position. 
     In some cases during inspiration, the air inlet may be at least partially blocked by an object such as a finger or a thumb of the patient which in turn blocks the air flow entering through the air inlet  104 . Such blockage of the air inlet  104  may lead to a malfunction of the breath-actuated mechanism and/or cause incomplete or ineffective delivery of the medicament to the patient. 
     In some cases, during inspiration the air inlet cover  116  may be at least partially blocked by an object such as a finger or a thumb of the patient which in turn blocks the air flow entering through the air inlet  104 . Such blockage of the air inlet  104  may lead to a malfunction of the breath-actuated mechanism and/or cause incomplete or ineffective delivery of the medicament to the patient. 
     In some cases, during inspiration at least one opening in the air inlet cover  116  may be blocked by an object such as a finger or a thumb of the patient which in turn blocks the air flow entering through the air inlet  104 . Such blockage of the air inlet  104  may lead to a malfunction of the breath-actuated mechanism and/or cause incomplete or ineffective delivery of the medicament to the patient. 
     Referring to  FIG. 3 , the present disclosure is directed towards a system  200  for detecting an obstruction of the air inlet  104  of the inhaler  100 . The obstruction may be caused by an object  202 . e.g., one or more fingers or a thumb of the patient using the inhaler. The system  200  includes a sensor  204 . The sensor  204  is disposed proximal to the air inlet  104 . The sensor  204  is configured to detect the obstruction of the air inlet  104  and generate an output signal indicative of the obstruction. Further, the sensor  204  may be configured to emit detection signals  208  towards the air inlet  104 . In an example, the sensor  204  may be configured to emit pulsed signals to detect the obstruction of the air inlet  104 . 
     In embodiments, the sensor  204  can be activated based upon a detection of a predefined inhaler preparation signature and later deactivated after an inhalation maneuver has been completed. This may be desirable in order, for instance, to minimize power consumption in contrast to if the sensor was always active. It should be understood, however, that the sensor could be continuously active and the feedback device configured to distinguish between detected obstructions when the device is not being used and detected obstructions when the device is in use. In another embodiment, the sensor can be activated and deactivated using an on-off switch. It should be noted that the term “predefined inhaler preparation signature” used herein may refer to a parameter that indicates usage of the inhaler  100 , such as, temperature, motion, orientation, and the like. Such parameters that correspond to the predefined inhaler preparation signature may be detected by sensors that may be present onboard the inhaler  100 . For example, the sensor  204  may be activated based on a movement of the inhaler  100  detected by an accelerometer or any other motion sensor associated with the inhaler  100 . 
     In some embodiments the sensor  204  is a proximity sensor. 
     Exemplary sensors  204  include an ultrasonic sensor, an optical sensor, a laser detector, a force sensor, and a temperature sensor. When the sensor  204  is an ultrasonic sensor, the ultrasonic sensor constantly pulses out wave signals and calculates nearness of a surface based on a time duration it takes to receive a return signal from the surface. Thus, detection of the object  202  within a range of the ultrasonic sensor results in generation of an output signal corresponding to the obstruction of the air inlet  104 . A single ultrasonic element can be used for both emission and reception of the ultrasonic waves. A single oscillator can emit and receive ultrasonic waves alternately. Further, in an example, the ultrasonic sensor may be programmed to detect any obstruction within a predefined periphery of the air inlet  104  or the air inlet cover  116 . 
     When the sensor  204  is an optical sensor, the optical sensor may include a sender and a receiver. The sender transmits detection signals which may be visible light signals or infrared light signals. The receiver constantly detects signals that reflect from a background environment, such as for example the wall  134  or the air inlet cover  116  or a separate reflector element. In such cases, the wall  134  of the air inlet  104 , the air inlet cover  116 , or the separate reflector element is designed to have a characteristic optical reflection. When the object  202  with a different surface characteristic, e.g., color, roughness, etc., is moved across a signal pathway, light reflection off the object  202  is detected to be different than light reflection from the background environment. This difference in light reflection is detected as an obstruction of the air inlet  104  and results in the generation of an output signal. The sender and receiver can be integrated together in the same sub-housing or they can be in separate housings. 
     In embodiments, the sensor can be configured as a through beam sensor. In a through beam sensor configuration the sender and receiver are oriented such that the light sending and light receiving elements are facing each other across a linear distance. The light signal can be transmitted directly to the receiver and the sensor operates by detecting whether an interruption in the signal has occurred. In operation, an interruption in the visible or infrared light signal by the object  202  may be detected as an obstruction of the air inlet  104  and results in the generation of an output signal. 
     When the sensor  204  is embodied as a laser detector, the laser detector includes a sender and a receiver. The sender constantly transmits detection signals and the receiver detects signals that are reflected by a background environment, such as the wall  134  or the air inlet cover  116 . Changes in the laser signal may be analyzed to detect any obstructions. 
     Further, the sensor  204  may include force sensors, such as piezoelectric sensors, strain gauges, or Microelectromechanical systems (MEMs) based sensing technologies for measuring strain and capacitance. The sensor  204 , embodied as a force sensor, may be positioned on or the air inlet cover  116 , within the air inlet cover  116 , or in contact with the air inlet cover  116 . When a force exerted on the air inlet cover  116  exceeds a predefined threshold, an output signal is generated by the force sensor. Alternatively, the force sensor may be located adjacent to perimeter of the air inlet opening. When a force exerted on the force sensor adjacent to the air inlet opening exceeds a predefined threshold, an output signal is generated by the force sensor. The predefined threshold may in some embodiments be equal to zero or about zero as the air inlet  104  is ideally free of any obstructions. The force sensor may also be configured to detect a spike in force as the obstruction approaches the air inlet  104 . The term force sensor includes touch sensors. In some embodiments, the force sensor is a resistive-type touch sensor. 
     In some embodiments, the force sensor is configured as a multi-layer laminate attached to air inlet cover and/or the housing adjacent to the air inlet opening. In some embodiments, the force sensor is configured as a multi-layer laminate incorporated within the air inlet cover and/or the housing adjacent to the air inlet opening. 
     Further, the sensor  204  may embody a temperature sensor that may be on the air inlet cover  116  or may be in contact with the air inlet cover  116 . The temperature sensor calibrates to the room temperature upon activation of the inhaler  100  based on the predefined inhaler preparation signature. When the predefined inhaler preparation signature is embodied as temperature values, any change in temperature beyond a threshold temperature value for the predefined inhaler preparation signature results in generation of an output signal. Alternatively, the temperature sensor may be placed adjacent to perimeter of the air inlet opening. The temperature sensor may also be configured to detect a spike in temperature as the obstruction approaches the air inlet  104 . 
     In the illustrated embodiment, the sensor  204  is disposed on the actuator housing  102 . The sensor  204  is disposed generally perpendicular to the air flow path “F”. The sensor  204  is disposed proximal to the air inlet  104 . More particularly, the sensor  204  is mounted on the air inlet cover  116 . For example, the sensor  204  may be mounted on an upper surface of the air inlet cover  116 . A sensitivity or range of the sensor  204  is programmed to be restricted to the periphery of the air inlet  104  and/or the air inlet cover  116 , such that the sensor  204  can only detect obstructions caused by the object  202  around the periphery of the air inlet  104 . When the sensor is activated, the sensor  204  continuously transmits detection signals. Further, a receiver  210  (depicted in  FIG. 4 ) may be mounted on another end, for example, behind the air inlet  104 , such that the receiver  210  receives signals reflected from the air inlet  104 . If the object  202  comes within the range of the sensor  204 , the sensor  204  detects the object  202  as the obstruction of the air inlet  104  and generates the output signal. It should be noted that the output signals may be sent to both adherence monitoring healthcare professionals and the patients. 
     Further, the system  200  includes a feedback device  206 . In the illustrated embodiment, the feedback device  206  is disposed on the actuator housing  102 . In other embodiments, the feedback device may be a separate component, such as a smartphone. The feedback device  206  may include one or more of an optical component, an audio component, and a haptic component. In one example, the display device  136  is embodied as the feedback device  206 . As depicted in  FIG. 4 , the feedback device  206  is communicably coupled with the sensor  204 . The feedback device  206  is configured to receive the output signal from the sensor  204  and generate a feedback signal indicative of the obstruction of the air inlet  104 . It should be noted that the sensor  204  or the feedback device  206  may include control circuitry (not depicted) that processes signals generated by the sensor  204 . The control circuitry may embody a single microprocessor or multiple microprocessors for receiving signals from various components of the system  200 . Numerous commercially available microprocessors may be configured to perform the functions of the control circuitry. The control circuitry may further include a memory to store data and algorithms therein required for operation of the inhaler  100 . 
     Further, the feedback device  206  notifies the patient regarding the obstruction of the air inlet  104  based on the receipt of the output signal. Thus, the feedback signal draws the patient&#39;s attention and hence prompts the patient to remove the finger or any other object that is obstructing the air inlet  104  (see  FIGS. 1 and 3 ). The feedback device  206  may provide the feedback signal to the patient regarding the obstruction of the air inlet  104  using various methods, for example, a Light Emitting Diode (LED) which may display or flash a color signature to notify the patient regarding the obstruction of the air inlet  104 , a buzzer sound that emits a sound frequency or tones to alert the patient, a haptic feedback, a text notification that may be displayed on the display device  136  (see  FIG. 1 ) of the inhaler  100 , an audible spoken word message, etc. The feedback device may also provide a feedback signal by wireless communication to a phone app. 
       FIG. 5  illustrates another embodiment of the present disclosure. In this embodiment, the sensor  204  is angularly mounted. More particularly, the sensor  204  is disposed obliquely with respect to the air flow path “F”. In an example, an angle “μl” is defined between the sensor  204  and the air flow path “F”. In some embodiments, the angle “μl” is between about 10 degrees and about 85 degrees. In the illustrated embodiment, the sensor  204  is disposed proximal to the air inlet  104 . In some embodiments, the sensor  204  may be attached to the air inlet cover or to the housing surrounding the air inlet. For example, the sensor  204  may be mounted on the upper surface of the air inlet cover  116 . 
     When the sensor is activated, the sensor  204  continuously transmits the detection signals  208 . Further, any obstruction caused by the presence of the object  202  across a pathway of the transmitted detection signals  208  is detected and the output signal is generated by the sensor  204 . More particularly, miniature reflectors may be mounted on the wall  134  or the air inlet cover  116  such that the reflectors reflect the detection signals  208  transmitted from the sensor  204 . If the object  202  comes within the range of the sensor  204 , the sensor  204  detects the object  202  as the obstruction of the air inlet  104  and generates the output signal. The feedback device  206  receives the output signal from the sensor  204  and generates the feedback signal indicative of the obstruction of the air inlet  104 . The feedback device  206  accordingly provides the feedback signal to the patient regarding the obstruction of the air inlet  104 . 
     Referring now to  FIG. 6 , another embodiment of the present disclosure is illustrated. In this embodiment, the inhaler  100  includes an add-on device  603  for sensing obstruction of an air inlet. In some embodiments, the add-on device  603  can be an electronic adherence monitoring add-on device that monitors usage of the inhaler  100 . The add-on device  603  is detachably connected to the actuator housing  102 . In one example, the add-on device  603  may be connected to the actuator housing  102  by a snap-fit connection or a threaded joint. Alternatively, a tongue and groove joint, straps, hook and loop fasteners, and the like may be used to connect the add-on device  603  with the actuator housing  102 . Further, the add-on device  603  may include a power source, such as batteries or cells, that may be present onboard the add-on device  603 . 
     In this embodiment, the add-on device  603  includes the sensor  204  disposed proximal to the air inlet  104 . More particularly, the sensor  204  is disposed on the add-on device  603 . The sensor  204  may be embedded in the add-on device  603  such that it is near the air inlet  104 . As illustrated, the sensor  204  is angularly mounted to the add-on device  603 . More particularly, the sensor  204  is disposed obliquely with respect to the air flow path “F”. In an example, an angle “B  1 ” is defined between the sensor  204  and the air flow path “F”. In some embodiments, the angle “B  1 ” is between about 10 degrees and about 85 degrees. Further, the sensor  204  is programmed such that it is constantly sending detection signals towards the wall  134  of the air inlet  104  and/or the air inlet cover  116 . Alternatively, the sensor  204  may be disposed generally perpendicular to the air flow path “F”. In such an example, the range of the sensor  204  may be programmed to be restricted to the periphery of the air inlet  104  and/or the air inlet cover  116 , such that the sensor  204  can only detect obstructions caused by the object  202  around the periphery of the air inlet  104 . 
     When the sensor is activated, the sensor  204  continuously transmits the detection signals  208 . Further, any obstruction caused by the presence of the object  202  across the pathway of the transmitted detection signals  208  are detected and the output signal is generated by the sensor  204 . More particularly, miniature reflectors may be mounted on the air inlet cover  116  such that the reflectors reflect the detection signals  208  transmitted from the sensor  204 . If the object  202  comes within the range of the sensor  204 , the sensor  204  detects the object  202  as the obstruction of the air inlet  104  and generates the output signal. The feedback device  206  receives the output signal from the sensor  204  and generates the feedback signal indicative of the obstruction of the air inlet  104 . In this embodiment, the feedback device  206  is disposed on the add-on device  603 . The feedback device  206  accordingly provides the feedback signal to the patient regarding the obstruction of the air inlet  104 . 
       FIG. 7  illustrates another embodiment wherein an inhaler  700  includes an add-on device  703 . The add-on device  703  may be detachably connected to the inhaler  700  by a snap-fit connection or a threaded joint. Alternatively, a tongue and groove joint, straps, hook and loop fasteners, and the like may be used to connect the add-on device  703  with an actuator housing  702 . Further, the add-on device  703  may include a power source, such as batteries or cells, that may be present onboard the add-on device  703 . 
     The add-on device  703  is similar in operation to the add-on device  603  depicted in  FIG. 6 . The inhaler  700  includes the actuator housing  702  and a mouthpiece  706 . A function and structure of the actuator housing  702  and the mouthpiece  706  are similar to that of the actuator housing  102  and the mouthpiece  106 , respectively, associated with the inhaler  100  depicted in  FIG. 3 . In this embodiment, the air inlet  704  is defined at a lower portion  705  of the inhaler  700 . The air inlet  704  includes an air inlet cover  716  similar to the air inlet cover  116  depicted in  FIG. 2 . The inhaler  700  includes a system  738  that is similar to the system  200  described above. Further, the system  738  includes the sensor  740  and the feedback device  742  that are similar in operation to the sensor  204  and the feedback device  206 , respectively, explained above. In this embodiment, the add-on device  703  includes the sensor  740  disposed proximal to the air inlet  704 . The sensor  740  is disposed generally perpendicular to an air flow path “F 1 ” defined by the actuator housing  702 . In one example, a range of the sensor  740  is programmed to be restricted to a periphery of the air inlet  704  and/or the air inlet cover  716 , such that the sensor  740  can only detect obstructions around the periphery of the air inlet  704 . 
     When the sensor is activated, the sensor  740  continuously transmits detection signals  745 . Further, any obstruction across a pathway of the detection signals  745  are detected and an output signal is generated by the sensor  740 . More particularly, miniature reflectors may be mounted on the air inlet cover  716 , such that the reflectors reflect the detection signals  745  transmitted from the sensor  740 . If the object  202  comes within the range of the sensor  740 , the sensor  740  detects the object  202  as the obstruction of the air inlet  704  and generates the output signal. 
     The feedback device  742  receives the output signal from the sensor  740  and generates a feedback signal indicative of the obstruction of the air inlet  704 . In this embodiment, the feedback device  742  is disposed on the add-on device  703 . Further, the feedback device  742  provides the feedback signal to the patient regarding the obstruction of the air inlet  704  based on the receipt of the output signal. For example, the feedback device  742  may provide the feedback signal to the patient regarding the obstruction of the air inlet  704  using an LED which may display or flash a color signature to notify the patient regarding the obstruction of the air inlet  704 , a buzzer sound that emits a sound frequency or tones to alert the patient, a haptic feedback, a text notification that may be displayed on a display device (not depicted) of the inhaler  700 , etc. 
     In another example, the sensor  740  may be programmed in such a way that it is constantly receiving signals returned from a bottom portion  744  of the mouthpiece  706 . In yet another example, the sensor  740  is angularly mounted to the add-on device  703 . More particularly, the sensor  740  is disposed obliquely with respect to the air flow path “F 1 ”. In an example, an angle “Cl” is defined between the sensor  740  and the air flow path “F”. In some embodiments, the angle “Cl” is between about 10 degrees and about 85 degrees. Accordingly, the sensor  740  is programmed such that it is constantly receiving signals returned from the wall  734  of the air inlet  704  and/or the air inlet cover  716 . Such an orientation of the sensor  740  can be used when the patients cover the air inlet  704  with their lips which is a common problem with inhalers having the air inlet  704  proximal to the mouthpiece  706 . 
       FIG. 8  illustrates the inhaler  100  according to another embodiment of the present disclosure. In this embodiment, the sensor  204  is mounted within the air flow path “F”. The sensor  204  is disposed proximal to the air flow path “F”. The sensor  204  is disposed obliquely to the air flow path “F”. Further, the sensor  204  is programmed such that it is constantly receiving signals returned from the wall  134  of the air inlet  104  and/or the air inlet cover  116 . Alternatively, the sensor  204  is disposed generally perpendicular to the air flow path “F”. In such an example, the range of the sensor  204  may be programmed to be restricted to the periphery of the air inlet  104  and/or the air inlet cover  116  such that the sensor  204  can only detect obstructions caused by the object  202  around the periphery of the air inlet  104 . 
     When the sensor is activated, the sensor  204  continuously transmits the detection signals  208 . Further, any obstruction across the pathway of the detection signals  208  are detected and the output signal is generated by the sensor  204 . More particularly, miniature reflectors may be mounted on the air inlet cover  116  such that they reflect the detection signals  208  transmitted from the sensor  204 . In some examples, a reflected signal that varies from an ideal reflected signal may be registered as an obstruction in the signal pathway. If the object  202  comes within the range of the sensor  204 , the sensor  204  detects the object  202  as the obstruction of the air inlet  104  and generates the output signal. The feedback device  206  receives the output signal from the sensor  204  and generates the feedback signal indicative of the obstruction of the air inlet  104 . The feedback device  206  accordingly provides the feedback signal to the patient regarding the obstruction of the air inlet  104 . Referring now to  FIG. 9A , another embodiment of an inhaler  900  is illustrated. The inhaler  900  includes an actuator housing  902  and a mouthpiece  906 . A function and structure of the actuator housing  902  and the mouthpiece  906  are similar to that of the actuator housing  102  and the mouthpiece  106 , respectively, associated with the inhaler  100  depicted in  FIG. 3 . Further, the actuator housing  902  includes an air inlet  904 . The air inlet  904  may include an air inlet cover  916  similar to the air inlet cover  116  depicted in  FIG. 2 . The inhaler  900  includes a system  938  that is similar to the system  200  described above. Further, the system  938  includes the sensor  940  and the feedback device  942  that are similar in operation to the sensor  940  and the feedback device  942 , respectively, explained above. The sensor  940  is disposed generally parallel to an air flow path “F 2 ” defined by the actuator housing  902 . In an example, the range of the sensor  940  may be programmed to be restricted to a predefined range above a periphery of the air inlet  904  and/or the air inlet cover  916  such that the sensor  940  can only detect obstructions up to the predefined range above the periphery of the air inlet cover  916 . 
     When the sensor is activated, the sensor  940  continuously transmits detection signals  945 . The sensor  940  is programmed such that the air inlet cover  916  constantly reflects the detection signals  945  transmitted from the sensor  940 . Any obstruction of the air inlet  904  alters the reflected signals that are detected by the sensor  940 . If the signal alteration caused by the obstruction exceeds a predefined signal change, an output signal is generated by the sensor  940 . The term “predefined signal change” may be defined as an allowable signal alteration which when exists does not compromise an effectiveness of the inhaler  900 . The predefined signal change may be prestored in a memory of a control circuitry that may be associated with the sensor  940  or the feedback device  942 . Thus, if the object  202  comes within the range of the sensor  940 , the sensor  940  detects the object  202  as the obstruction of the air inlet  904  and generates the output signal. 
     The feedback device  942  receives the output signal from the sensor  940  and generates a feedback signal indicative of the obstruction of the air inlet  904 . Further, the feedback device  942  provides the feedback signal to the patient regarding the obstruction of the air inlet  904  based on the receipt of the output signal. For example, the feedback device  942  may provide the feedback signal to the patient regarding the obstruction of the air inlet  904  using an LED which may display or flash a color signature to notify the patient regarding the obstruction of the air inlet  904 , a buzzer sound that emits a sound frequency or tones to alert the patient, a haptic feedback, a text notification that may be displayed on a display device (not depicted) of the inhaler  900 , etc. 
     The inhaler  900  also includes a cover member  946 . The cover member  946  is movable between an open position and a closed position. The cover member  946  is depicted in the open position in  FIG. 9A  and in the closed position in  FIG. 9B . In one example, the cover member  946  moves between the open and closed positions based on control signals received from a control module (not depicted) associated with the inhaler  100 . More particularly, an actuator (not depicted) may move the cover member  946  based on the control signals received from the control module. Further, a spring  948  biases the cover member  946  to the open position, such that the actuator moves the cover member  946  against a biasing of the spring  948 . The cover member  946  is pivotally coupled to a first member  950  such that the cover member  946  pivots with respect to the first member  950  to switch between the open and closed positions. 
     As depicted in  FIG. 9B , the cover member  946  is configured to cover the sensor  940  in the closed position. More particularly, during the delivery of the medicament to the patient, the cover member  946  covers the sensors  940 . In the closed position, the cover member  946  is in contact with a second member  952 . The cover member  946  may include a flap, a vane, or a valve. The cover member  946  moves between the open and closed positions to isolate the sensor  940  from the air flow path “F 2 ” during the delivery of the medicament to the patient. In another example, the sensor  940  may be further protected by a sensor shield such that the sensor shield does not affect a performance of the sensor  940 . The cover member or sensor shield can be used to protect the sensor from possible contamination such as dust, dirt, or water. 
       FIG. 10A  illustrates another embodiment of an inhaler  1000 . The inhaler  1000  is similar to the inhaler  600  explained in relation to  FIG. 6 . The inhaler  1000  includes an actuator housing  1002  and a mouthpiece  1006 . In this embodiment, the air inlet  1004  is defined at a lower portion  1005  of the inhaler  1000 . The air inlet  1004  includes an air inlet cover  1116  similar to the air inlet cover  116  depicted in  FIG. 2 . The inhaler  1000  includes a system  1038  that is similar to the system  200  described in relation to  FIGS. 3 and 4 . Further, the system  1038  includes the sensor  1040  and the feedback device  1042  that are similar in operation to the sensor  204  and the feedback device  206 , respectively, explained in relation to  FIGS. 3 and 4 . The sensor  1040  is disposed generally parallel to an air flow path “F 3 ” defined by the actuator housing  1002 . In one example, a range of the sensor  1040  is programmed to be restricted to a predefined range above a periphery of the air inlet  1004  and/or the air inlet cover  1016  such that the sensor  1040  can only detect obstructions up to the predefined range above the periphery of the air inlet cover  1016 . 
     When the sensor is activated, the sensor  1040  continuously transmits detection signals  1045 . The sensor  1040  is programmed such that the air inlet cover  1016  constantly reflects the detection signals  1045  transmitted from the sensor  1040 . Any obstruction of the air inlet  1004  alters the reflected signals that are detected by the sensor  1040 . If the signal alteration caused by the obstruction exceeds a predefined signal change, an output signal is generated by the sensor  1040 . The predefined signal change may be prestored in a memory of a control circuitry that may be associated with the sensor  1040  or the feedback device  1042 . 
     Thus, if the object  202  comes within the range of the sensor  1040 , the sensor  1040  detects the object  202  as the obstruction of the air inlet  1004  and generates the output signal. The feedback device  1042  receives the output signal from the sensor  1040  and generates a feedback signal indicative of the obstruction of the air inlet  1004 . The feedback device  1042  provides the feedback signal to the patient regarding the obstruction of the air inlet  1004  based on the receipt of the output signal. For example, the feedback device  1042  may provide the feedback signal to the patient regarding the obstruction of the air inlet  1004  using an LED which may display or flash a color signature to notify the patient regarding the obstruction of the air inlet  1004 , a buzzer sound that emits a sound frequency or tones to alert the patient, a haptic feedback, a text notification that may be displayed on a display device (not depicted) of the inhaler  1000 , etc. 
     The inhaler  1000  may also include a cover member  1046 . The cover member  1046  is movable between an open position and a closed position. The cover member  1046  is depicted in the open position in  FIG. 10A  and in the closed position in  FIG. 10B . In one example, the cover member  1046  moves between the open and closed positions based on control signals received from the control module associated with the inhaler  100 . More particularly, an actuator (not depicted) may move the cover member  1046  based on the control signals received from the control module. Further, a spring (not depicted) biases the cover member  1046  to the open position, such that the actuator moves the cover member  1046  against a biasing of the spring. The cover member  1046  is pivotally coupled to a first member  1050  such that the cover member  1046  pivots with respect to the first member  1050  to switch between the open and closed positions. 
     As depicted in  FIG. 10B , the cover member  1046  is configured to cover the sensor  1040  in the closed position. More particularly, during the delivery of the medicament to the patient, the cover member  1046  covers the sensors  1040 . In the closed position the cover member  1046  is in contact with a second member  1052 . The cover member  1046  may include a flap, a vane, or a valve. The cover member  1046  moves between the open and closed positions to isolate the sensor  1040  from the air flow path “F 3 ” during the delivery of the medicament to the patient. 
     In another example, the sensor  1040  may be further protected by a sensor shield such that the sensor shield does not affect a performance of the sensor  1040 . 
       FIG. 11  illustrates a flowchart for a method  1100  of detecting the obstruction of the air inlet  104 ,  704 ,  904 ,  1004  of the inhaler  100 ,  700 ,  900 ,  1000  used for delivering the medicament to the patient. At step  1102 , the sensor  204 ,  740 ,  940 ,  1040  detects the obstruction of the air inlet  104 ,  704 ,  904 ,  1004 . The sensor  204 ,  740 ,  940 ,  1040  emits the detection signals  208 ,  745 ,  945 ,  1045  towards the air inlet  104 ,  704 ,  904 ,  1004  for detecting the obstruction of the air inlet  104 ,  704 ,  904 ,  1004 . The sensor  204 ,  740 ,  940 ,  1040  is activated based upon the detection of the predefined inhaler preparation signature. Further, during the delivery of the medicament to the patient, the cover member  946 ,  1046  covers the respective sensors  940 ,  1040 . 
     At step  1104 , the sensor  204 ,  740 ,  940 ,  1040  generates the output signal indicative of the obstruction. At step  1106 , the feedback device  206 ,  742 ,  942 ,  1042  receives the output signal from the sensor  204 ,  740 ,  940 ,  1040 . At step  1108 , the feedback device  206 ,  742 ,  942 ,  1042  generates the feedback signal. The feedback signal is indicative of the obstruction of the air inlet  104 ,  704 ,  904 ,  1004 . The feedback signal includes at least one of an optical feedback signal, an audio feedback signal, and the haptic feedback signal. 
     It should be noted that positioning of the sensors  204 ,  740 ,  940 ,  1040  mentioned above may vary depending on a position of the respective air inlets  104 ,  704 ,  904 ,  1004  and the particular airflow path of an inhaler. The teachings of the present disclosure can be integrated into an inhaler or provided as an add-on device that can be attached to an inhaler. The system  200 ,  738 ,  938 ,  1038  can be applied to inhalers of the press-and-breathe type, breath-actuated type, dry powder type, soft mist type, etc., without limiting the scope of the present disclosure. 
     Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations can be substituted for the specific embodiments depicted and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.