US 20060011196 A2
Abstract of the Disclosure
An apparatus for use in conjunction with a metered dose inhaler which includes a novel valve system to aid in the delivery of aerosolized medicament to a subject. The apparatus also includes a novel rotational flow generator to aid in the useable delivery of said medication and avoid its loss either in the apparatus or by non-useful delivery to said subject.
1. An apparatus for aerosol medication delivery, comprising:
a holding chamber having a first and second ends, the first end being adapted to accept a source of aerosol medicament; and
a mouthpiece member provided at the second end of the holding chamber, for delivering aerosol medicament to a subject, the mouthpiece member comprising:
a housing defining a passage through which aerosol medicament can be supplied to a subject and comprising a sidewall in which an opening is formed that opens to the outside of the housing; and
a one-piece valve member comprising a first valve element in fluid communication with the mouthpiece and the holding chamber, the first valve element within the passage to permit delivery of aerosol to a subject during inhalation and blocks the passage during exhalation and a second valve element in fluid communication with the mouthpiece and the opening in the side wall, the second valve element to prevent air from reaching the subject through the opening in the sidewall of the housing during inhalation and permits the flow of air to the outside of the housing from the passage during exhalation,
wherein the first valve element extends axially away from the housing when the apparatus is in a rest position.
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the adaptor member is provided at the second end of the holding chamber, and
the delivery member is releasably connected to the adaptor member.
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38. A mouthpiece member for aerosol medicament delivery, having first and second ends, the first end being adapted to accept a source of aerosol medicament and the second end being adapted for delivering aerosol medicament to a subject, the mouthpiece member comprising:
a housing defining a passage through which aerosol medicament can be supplied to a subject and comprising a sidewall in which an opening is formed; and
a one-piece valve member comprising a first valve element that permits delivery of aerosol to a subject during inhalation and blocks the passage during exhalation and a second valve element that blocks the opening in the sidewall of the housing during inhalation and permits the flow of air to the outside of the housing from the passage during exhalation, wherein the first valve element extends axially away from the housing in a rest position.
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40. An apparatus for aerosol medication delivery, comprising:
a mouthpiece member for delivering aerosol medicament to a subject,
a holding chamber having first and second ends, the mouthpiece member being disposed at the second end of the chamber and
a receptacle member being disposed at the first end of the chamber, the receptacle member comprising:
an opening adapted to accept a source of aerosol medicament,
a vent permitting fluid communication for the entry of outside air into the holding chamber, and
a means for imparting a rotational flow to the outside air entering the holding chamber,
wherein at least a portion of the means for imparting rotation flow is spaced from
the vent and at least partially obscuring the vent when the receptacle member is viewed
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The present invention is directed to apparatus for delivering aerosol medicament to a subject in need of the medicament. Delivery systems start with an aerosol-generating device. One common example of such devices is a pressurized metered dose inhaler (MDI). MDIs use pressurized gases to disperse medicament as tiny particles or droplets for delivery to the subject. By depressing the MDI, a known quantity of gas, and thereby of medicament, is ejected from the MDI. MDIs have been used with various types of diverse apparatus, in attempts to improve the delivery of this known quantity of medicament to the subject. Some problems associated with the delivery of medicament in an aerosol form include, but are not limited to, wastage of medicament in the delivery apparatus, delivery at too high speeds so that medicament sticks to the back of the subject's throat or is inhaled into the subject's sinuses rather than being received into the lungs, ejection of medicament out of the apparatus towards a subject without inhalation thereby, and ejection of medicament from the MDI upon exhalation by the subject into the apparatus prior to inhalation.
In one aspect, the present invention provides a mouthpiece with a valve for controlling the delivery of aerosolized medicament to a subject. The mouthpiece includes a housing that defines a passage through which the medicament flows to the subject. The housing has a one-piece valve system that permits passage of medicament aerosol to the subject during inhalation, but does not permit the passage of the subject's breath in the upstream direction during exhalation, with the exhaled breath being expelled through an opening in the sidewall of the housing.
Another aspect of the present invention combines this mouthpiece and valve system with a holding chamber, which is disposed between the mouthpiece and the source of aerosol. In a further feature of this aspect of the invention, the interior of the holding chamber has anti-electrostatic properties to reduce the amount of medicament adhering to the walls of the holding chamber and thereby increase the delivery efficiency of the system.
In a further aspect of the present invention, a holding chamber is provided with a receptacle member adapted to accept a source of aerosol medicament. The receptacle member may aid in the efficient delivery of medicament to the subject, for example by being vented to allow outside air to be mixed with the medicament aerosol in the holding chamber. In addition, if a rotation is imparted to the outside air brought into the holding chamber, the adhesion of medicament to the walls of the holding chamber can be reduced and the effort necessary to inhale through an apparatus of this type may be reduced.
At the second end is a mouthpiece member 100 for delivering aerosol medicament to a subject through a valve 150. The mouthpiece member includes a housing 101 that defines a passage 102 through which aerosol medicament can be supplied to a subject and has an opening 103 that opens to the outside of the housing. The valve, discussed below, is of one-piece construction. During inhalation the valve permits the flow of aerosol medicament from the holding chamber to the subject, while blocking the inflow of outside air to the passage 102 through the sidewall of the housing of the mouthpiece member. During exhalation, the valve blocks the flow of exhaled air upstream in the direction of the holding chamber, and permits the exhaled air to be exhausted through the sidewall of the housing.
In an exemplary embodiment, the housing 101 is composed of a delivery member 110 and an adaptor member 170. The opening 103 may be defined, as it is in part in the exemplary embodiment, by a notch 186 in the adaptor member. The delivery member and adaptor member may be releasably connected by a quick release mechanism 182. In the exemplary embodiment, the quick release mechanism is a flexible wall, upon which a positioning element 175 may be located. Also, in the exemplary embodiment, the housing is transparent. This has the advantage that it allows for the subject to visually verify the operation of the valve, to ensure opening and closing during treatment.
The duck-bill is a shape predominantly that of a wedge with a very narrow split across the apex of the wedge. The split is narrow enough that the two edges forming the ends of the duck-bill are substantially in contact when there is no external pressure on the duck-bill. The duck-bill has a span, a height, and a thickness. The height of the duck-bill is the vertical distance between the apex of the wedge where the split is located and the base. The span is the distance of the split across the thin edge of the wedge and the height. The span is sufficiently narrow that the apex of the duck bill will fit within the delivery member without contacting it. Thus, the dead zone within the delivery member is minimized by the valve extending therein. The valve may be as wide as possible to provide for easier inhalation, but just narrower than the passage so that the duck-bill sides do not receive pressure and the lips of the duck-bill are not parted except by inhalation.
Dead space refers to the volume of the apparatus containing air which is rebreathed. Dead space is inherent in any valve-based system enclosed within a mouthpiece or mask; it is the space between the mouth of a subject and the valve. Any subject has a limited volume of air that may be inhaled, and which then is exhaled. This is the subject's tidal volume. The inhalation air will contain both oxygen and medicament. The exhalation air will contain carbon dioxide. In a sealed system, all inhalation air will come through the valve and will contain a preferable mixture of medicament laden air. However, this inhalation air will be combined with whatever gases remain sealed within the dead space on their way to being actually inhaled into the subject's respiratory tract. Similarly, when the subject exhales, all air must pass through this dead zone on the way out the exhaust portion of the valve system.
Because the subject will be incapable of forcing a complete vacuum within this sealed system, the dead space will contain gases that then will be re-inhaled during the next breathing cycle. Given that the volume of the subject's lungs is fixed, the larger the volume of the system's dead space, the smaller the volume of medicament laden air the subject will receive with each breathing cycle. Thus, the larger the volume of dead space, the less efficient the system because increasing dead space causes a buildup of carbon dioxide and rebreathing. Rebreathing carbon dioxide can have an adverse effect on breathing rates and patterns, especially for small children who have very small tidal volumes. Duck-bill valves are more efficient than diaphragm valves because the volume encompassed by the duck-bill is subtracted from space that otherwise would be dead space in a diaphragm-based system.
The duck-bill is thin enough that the sides of the wedge will flex when the atmospheric pressure on the opposite side of the base from the duck-bill is greater than that above the duck-bill. This causes the edges of the duck-bill to part, letting air flow through the duck-bill in the direction from the base to mouthpiece. Thus, in the present embodiment, air is permitted to flow through the mouthpiece to a subject during inhalation. The duck-bill closes automatically at the end of inhalation when the atmospheric pressure differential is removed. Thus, the flow of exhaled air upstream of the valve to the holding chamber is prevented during exhalation.
The exemplary embodiment of the present invention provides two hinged flaps 153 extending from on or near the perimeter of the base. Each hinged flap 153 is sized so as to be able to cover a corresponding notch 147 when assembled. Each flap is placed on the base at such a position and at such an angle that when the base is placed onto the positioning pins of the mouthpiece, the flap covers one of the notches 147. The flap is hinged onto the base so that it may cover the notch 147 during inhalation, thereby preventing the flow of outside air into the interior of the housing through the opening in the sidewall of the housing. When the mouthpiece of the apparatus of the exemplary embodiment is assembled, the notch of the delivery member 147 and the aforementioned notch of the adaptor member 186 may be aligned radially, and the hinged outgas flap 153 is disposed between these notches. The flexible material forming each of the outgas flaps is sufficiently thin to allow an outgas flap to flex through at least a few degrees of flexibility when differences in relative atmospheric pressure caused by human breathing exert flexing pressure on said flap, thereby moving the flap away from the notch 147 during exhalation and allowing exhaled air to pass out of the mouthpiece through the notch 186.
Ridges 125 may be provided for placement of the subject's lips, or to aid in the placement of an adaptor mask on the outside of the delivery member. Shaped correctly, a ridge 125 may be used to seal and mount such a mask with a tight pressure fit. These ridges are placed approximately halfway down the upper section, and are wedge shaped in the exemplary embodiment. Specifically, they are formed by the upper and lower thickness measurements being equal at the side points and the lower thickness being greater than the upper thickness at the lip points.
The exterior wall 133 may be substantially parallel to the sidewall 128 and extends from the top surface in a direction away from the lip end of the subject side section. The exterior wall has an interior surface and an exterior surface, the interior surface being closer to the interior opening of the connecting ring. In the exemplary embodiment, there are two contact openings 134 in the top surface, which are disposed approximately equidistantly around the circumference of the top surface. Each contact hole is adapted to accept a portion of the adaptor member, to help hold the two members of the mouthpiece securely together. On the interior surface of the exterior wall, there may be provided two engaging members 136, or catches, each being below a contact hole. They are wedge shaped and oriented with the thin end of the wedge towards the adaptor side for ease in connecting and resistance to disconnecting. In the exemplary embodiment, each has a width less than that of the corresponding contact opening above the catch, a length less than that of the distance between the top and bottom of the exterior wall of the connecting ring, and a height less than the length.
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The delivery side end of the conical adaptor member may have an opening 185 of substantially the same size as the opening 155. An airtight seal may be formed between the opposing surfaces of the adaptor member and the delivery member by the valve. That is, the valve base 151 may have opposing surfaces arranged to meet those of the adaptor member and the delivery member and form an airtight seal when the apparatus is assembled. The exemplary embodiment's adaptor member 170 has a rim 180 around the opening 185 with four positioning openings 181 in the rim, one for each pin 141. Thus, when the two members are joined, the four pins of the delivery member drop into these openings in the exemplary embodiment.
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The use of such material reduces the risk of resistance to medicament flow by static attraction between the particles of medicament and the holding chamber wall. Alternatively, the surface of a holding chamber of any material may be treated with an anti-electrostatic coating or process to achieve this advantage. In the exemplary embodiment using a metal tube, the tube is anodized which provides the advantage of sealing the micro-porosity of such a tube's surface and stabilizing it against oxidation.
The opening 350 of the receptacle of the exemplary embodiment may be sized to accept several different types of aerosol medicament sources such as MDIs. The collar 370 is sufficiently long and flexible to form a seal with the aerosol medicament source when one is admitted into the receptacle. The supporting wall 340 of the exemplary embodiment is provided with cyclone baffles 330 placed upon the outside of the wall (relative to the opening) and support ribs 360 radially placed upon the inside of the wall. The support ribs 360 extend from the wall towards the collar 370. They are sized so that there is space for the collar to be pressed up against the ribs when a typical MDI is inserted into the opening. Thus, an airtight seal may be formed around the source of the aerosol medicament. The support ribs of the exemplary embodiment provide support to the source of aerosol medicament by holding that source against the structure of the collar.
The vents 320 allow outside air to be drawn into the holding chamber during inhalation. This helps to push the aerosol medicament to the subject during inhalation. Each cyclone baffle 330 extends towards the base and is aligned with a vent 320 so that the point where the baffle reaches the base is just beyond the vent. The baffle thus covers the vent. The baffle may have a width sufficient to form a seal between the supporting wall and the tube wall of the chamber. By using the baffle to direct airflow coming through the vents, a rotational flow is imparted to the air entering the chamber through the vents. In the exemplary embodiment, the placement of the cyclone baffles above the vents and next to the wall of the holding chamber wall directs outside air to and along the wall of the holding chamber. This reduces the tendency for medicament to adhere to the wall of the holding chamber. Although each of the four vents have been provided with a cyclone baffle in the present embodiment, this may not be necessary in all cases.
The exemplary embodiment of the present invention is steam autoclavable either assembled or disassembled. This advantage arises from both the choice of materials used, as herein discussed, and the materials and methods of assembling the components of the invention, such as the quick release mechanism 182 and the use of high-temperature adhesive at the junction of adaptor member 170 and holding chamber 200. Further, the present invention is easily disassembled for cleaning and parts replacement by a non-technical person.
While a detailed description of the present invention has been provided above, the invention is not limited thereto. Modifications that do not depart from the scope and spirit of the invention will be apparent to those skilled in the art. The invention is defined by the claims that follow.