Abstract:
The present invention relates to a spray device (e.g., an inhaler) comprising an aerosol formulation administered to the respiratory or nasal tract in which the level of formulation remaining in the device can be readily inspected. The device comprises a glass vial ( 1 ) coated with a coating of polymeric material having at least one clear or translucent portion ( 4 ).

Description:
FIELD OF THE INVENTION 
     The present invention relates to a respiratory aid adapted to combat more reliably the symptoms of a subject with a respiratory disorder, in particular to a spray device (e.g., an inhaler) comprising an aerosol formulation administered to the respiratory or nasal tract. 
     BACKGROUND OF THE INVENTION 
     Various respiratory aids are now widely available to a subject wishing to self-administer therapeutic and preventative agents to combat the symptoms of a respiratory disorder such as asthma. These aids come in a range of shapes and sizes to suit the age and ability of the subject. Such respiratory aids include inhalers and auxiliary devices such as spacers, optimisation chambers, reservoirs, expansion chambers and deceleration chambers. 
     A common example of a respiratory aid is the inhaler which is a manually operated device used to dispense into the respiratory passages a discrete amount of a therapeutic or preventative agent (e.g., in the form of a spray). One of the benefits of an inhaler is that the subject is able to manage the respiratory disorder through self-administration of a preventative agent. A successful preventative regime relies on regular self-administration of the preventative agent to avert breathing difficulties and other respiratory symptoms. Breathing difficulties may occur suddenly and indiscriminately and their onset frequently leads to a loss in co-ordination. A second benefit of an inhaler is that sudden respiratory attacks may be treated by immediate self-administration of the desired therapeutic agent. The preventative and therapeutic benefits of the inhaler rely on the subject being able to locate reliably and effortlessly an inhaler with an at least partially charged container. 
     In principle inhalers are available in two types, namely an aerosol device powered by a propellant (e.g., a metered dose inhaler of the type described in inter alia GB-A-2293110) or a powder containing device (e.g., a metered dose powder inhaler). The therapeutic or preventative agent may be in dry powder or liquid (e.g., suspension) form and generally speaking is drawn into the respiratory passages by simultaneously dispensing the agent and taking a sharp intake of breath. 
     Most forms of aerosol inhaler comprise a metal container for the therapeutic or preventative agent and a discharge valve through which the agent may be dispensed continuously or discretely via a nozzle. For example, conventional metered dose inhalers comprise a metal canister secured to a metered dose valve. A determination of the number of doses remaining in the canister requires a manual record of the number of doses which have been dispensed (for example using a mechanical counter). Many counter devices of a mechanical type have been proposed. 
     U.S. Pat. No. 3,505,870 discloses a metal aerosol container with a transparent window in a small circular opening in the base. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is based on the recognition that the welfare of a subject having a respiratory disorder (such as asthma) may be improved by assisting them to rapidly and reliably assess the status of the container. More particularly, the present invention relates to a respiratory aid such as an inhaler adapted so that the subject may rapidly determine how much of the preventative or therapeutic agent remains within the container. 
     Thus viewed from one aspect the present invention provides a respiratory aid (e.g., a medical aerosol device) for use in self-administration of an agent for combating (e.g., preventing or treating) the symptoms of a respiratory disorder, said respiratory aid comprising:
         a container for the agent operatively connected to a discharge valve through which a therapeutically or preventatively effective amount of said agent may be dispensed via a nozzle and an actuator body adapted to actuate the valve, wherein the container comprises:   a glass vial coated with a coating of polymeric material, the coating of polymeric material having at least one clear or translucent portion arranged to permit observation of the level of agent in the container.       

     Viewed from a further aspect the present invention provides a medical aerosol device comprises a container and a discharge valve through which fluid may be dispensed via a nozzle, an actuator adapted to actuate the valve, the container comprising a glass vial coated with a layer of polymeric material, the polymeric material having at least one clear or translucent portion arranged to permit observation of the level of liquid in the container. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of a vial in accordance with the invention; 
         FIG. 2  is a perspective view of the vial shown in  FIG. 1 ; 
         FIG. 3  shows the vial and a metered dose inhaler body; 
         FIG. 4  shows the vial and an alternative metered dose inhaler body; and 
         FIG. 5  shows the vial with a nasal spray dispenser. 
     
    
    
     DETAILED DESCRIPTION 
     The respiratory aid may be any type of inhaler including one of the group consisting of a pressurised metered dose inhaler (both manually operable and breath actuated), an aerosol inhaler and a dry powder inhaler. 
     Preferably the actuator is adapted to directly or indirectly administer a therapeutically or preventatively effective amount of said agent into the respiratory passages of a subject through a delivery outlet, said delivery outlet being adapted to fit in the subject&#39;s mouth or nose or into an auxiliary device (such as a spacer or an optimisation chamber). 
     Glass vials have not previously been used for medical aerosol devices because of the risk of breakage if the device is dropped, a risk which is increased in distressed subjects suffering from an asthma attack. Not only are the shards of glass hazardous but the patient may not have a replacement device readily to hand. Thus the use of glass in accordance with the invention is somewhat contrary to conventional wisdom. Application of a polymeric coating may advantageously reduce the risk of injury and distress in the event of breakage. 
     The polymeric coating may be composed of a polyolefin such as polyethylene, polypropylene, polystyrene or copolymers or blends thereof. Alternative polymers include ABS, acetyl, acrylic and other polymers. Polypropylene is preferred. 
     In a first embodiment the clear or translucent portion may comprise a window of reduced thickness of polymer coating. The window may be formed by polishing the portion of reduced thickness or by polishing the polymer coating to form a polished portion of reduced thickness. 
     Alternatively the clear or translucent portion may comprise a portion of increased thickness, the portion being polished to provide a transparent or translucent surface. 
     Two windows may be provided on opposite sides of the vial to advantageously facilitate transmission of light. 
     In a preferred embodiment, the clear or translucent portion extends axially of the vial. Gradations or other markings may be provided on or adjacent to the window to indicate the number of doses available. 
     The device is preferably a metered dose inhaler device or nasal spray. 
     The container may comprise a conventional metered dose inhaler or nasal spray casing, a window being provided to facilitate observation of the liquid level within the vial. Gradations or other markings may be provided on the casing in addition to or instead of markings on the vial. 
     The invention is further described by means of example, but not in any limitative sense with reference to the accompanying drawings. 
       FIGS. 1 and 2  illustrate a vial in accordance with an embodiment of this invention. The vial includes a body portion  23  having a side wall  25  and a neck portion  24  disposed adjacent to the body portion. A glass vial  1  has a conventional aerosol outlet  2  secured by means of a crimped cap  3 . The vial  1  is formed of glass with an outer coating of polypropylene  6 . The coating includes a clear or translucent portion defining at least one window  4  extending in an axial direction and in a circumferential direction across a distance that is less than a circumference of the vial  1  so that a level of the agent in the vial  1  is visible through the coating. The window  4  extending axially of the vial is formed by polishing a portion of the polypropylene coating so that the level of liquid within the vial  1  can be observed. As shown in  FIGS. 1 and 2 , the window  4  is at least partially disposed on the side wall  25  of the body portion  23 . Gradations  5  allow a user to check whether the quantity of liquid available for dispensing is within predetermined maximum and minimum limits. 
       FIG. 3  shows the vial of  FIGS. 1 and 2  inverted for insertion into a conventional metered dose inhaler body  7 . The body  7  includes a nozzle  8  defining a mouthpiece  8 . The portion  9  of the body  7  into which the vial  1  is inserted may be composed of transparent or translucent material so that the vial  1  can be observed without removal from the body  7 . 
       FIG. 4  illustrates the vial  1  inverted for insertion into a Norton EASI-BREATHE (Registered Trade Mark) metered dose inhaler. The inhaler comprises a body portion  10  adapted to receive the vial  1  and having a pivotable cap  11  which may be opened to facilitate dispensing of the drug. A cap  12  secured to the body  10  may be twisted to prime the metered dose inhaler mechanism (not shown). 
     In use, the cap  12  may be removed from the body  10  to allow inspection of the vial  1 . Alternatively a window (not shown) may be provided in the side of the body  10  to facilitate inspection of the vial  1  without removal from the body  10 . 
       FIG. 5  illustrates a nasal spray device in accordance with an embodiment of this invention. The vial  1  is engaged in a cap  21  having an outlet  22  for insertion into the nasal cavity. The base  20  into which the body of the vial  1  is received incorporates a window  24  having gradations  25 . In use the window  4  is aligned with the window  24  so that the level of liquid within the vial  1  may be observed without removing the latter from the base  20 . 
     In this embodiment, the gradations  5  are optional but may serve to confirm to a patient by alignment with the gradations  25  that the vial is correctly inserted into the spray cap  21  and base  20 .