Surgery – Respiratory method or device – Means for mixing treating agent with respiratory gas
Reexamination Certificate
2002-05-10
2004-08-31
Dawson, Glenn K. (Department: 3761)
Surgery
Respiratory method or device
Means for mixing treating agent with respiratory gas
C128S200140, C128S200230, C128S203210
Reexamination Certificate
active
06782887
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to medicament respiratory delivery devices including pulmonary, intranasal and buccal respiratory delivery devices having more efficient delivery of a medicament to the respiratory system of a patient.
BACKGROUND OF THE INVENTION
Inhalers and atomizers are now commonly used primarily to deliver various liquid medicaments via the patient's or user's nose or mouth. As used herein, “medicament” includes any powder or liquid medicament, drug or vaccine or combinations thereof which may be administered from an respiratory delivery device through the user's nose or mouth, sometimes referred to herein as a medicament respiratory delivery device. More recently, the prior art has proposed unit dose disposable powder medicament delivery devices, such as disclosed in U.S. Pat. No. 5,215,221, wherein a predetermined quantity or unit dose of a powder medicament is sealed in a reservoir formed between opposed thermoplastic sheets and expressed or delivered by application of manual force to a thermoformed blister which, upon activation, breaks a burstable seal between the sheets at the entrance to the reservoir and fluidizes the powder medicament in the reservoir through a delivery tube. The sealed delivery tube is cut prior to use.
There are several considerations affecting the design and efficacy of medicament respiratory delivery devices. First, it is important to ensure that a predetermined quantity or dose of medicament is consistently delivered to the user with each application. Second, because respiratory therapy often requires numerous applications, the cost of providing the dosage should also be considered. Thus, it is desirable that the medicament respiratory delivery device consistently express substantially all of the medicament to the user and that the delivery device is not susceptible to user error in operation. Third, it is important that the medicament be properly disbursed or entrained in the conveying fluid. Further considerations include the operating complexity, cost of the device, portability and size of the delivery device. It would also be desirable in certain applications to provide a reusable delivery device with a disposable standard medicament cartridge containing a unit dose of medicament which can be easily handled and replaced in the delivery device by the user without error. In other applications, a disposable delivery device is desirable.
The embodiments of the medicament respiratory delivery devices and medicament cartridge of this invention provide a reproduceable, high level of clearance of medicament or emitted dose from the cartridge upon manual actuation of the device with modest gas pressure as well as improved efficiency in the delivery of that medicament.
SUMMARY OF THE INVENTION
The cartridge for a medicament respiratory delivery device of this invention includes a body having opposed ends, a passage through the body and through the opposed ends, a medicament stored in the passage and burstable or pierceable membranes covering and sealing the passage at the opposed ends of the body. In the preferred embodiments, the opposed ends of the cartridge body surrounding the passage are convex and the burstable membranes are stretched taut over the convex opposed ends and bonded thereto, sealing the passage. In one disclosed embodiment, the opposed ends of the body are frustoconical surrounding the passage and the membranes comprise a thin polyolefin film heat-sealed or fused to the opposed frustoconical ends of the body. The term polyolefin is understood to mean a polymer containing olefin units such as, for example, ethylene, propylene or 1-butene units or any other alpha-olefin. Polyolefin as used herein includes polyethylene, polypropylene, ethylene- .alpha. olefin copolymer, wherein the alpha olefin having from 3 to 20, preferably 4 to 8 carbon atoms, polyolefin copolymers made by polymerizing olefins in the presence of a metallocene catalyst, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer. In particular, it is desirable to use polyethylene, such as low-density, linear-low-density, very-low-density, medium-density, or high-density polyethylene, or polypropylene, such as a polypropylene homopolymer, ethylene-propylene copolymer, or ethylene-propylene block copolymer.
In one preferred embodiment, the polymeric films which form the burstable membranes are preferentially oriented polyolefin films, preferably uniaxially oriented polyethylene films, angularly related, wherein the films oriented on the opposed ends of the cartridge are most preferably oriented at approximately right angles. It has been found by the applicant that burstable membranes formed of preferentially or uniaxially oriented polyolefin film, most preferably polyethylene film, wherein the films are oriented at approximately right angles, results in improved delivery of the medicament from the body passage or reservoir to the respiratory system of the user and results in a consistently greater emitted dose. Polyolefin films can be oriented by drawing in one or both mutually perpendicular directions in the plane of the film to impart strength thereto using methods known in the art. Oriented polyolefin films include machine direction and transverse direction orientation. Oriented polyolefin films include uniaxially or biaxially oriented films, with uniaxially films being preferred having a draw ratio of at least 1.2. Uniaxially-oriented films have properties to their advantage for use as the burstable membrane, including relatively high stiffness, as indicated by the tensile modulus in a particular direction, usually the machine direction, compared to the transverse direction. Properties of the oriented polyolefin film can be dependent to a certain degree on the particular process conditions under which the polyolefin film was manufactured. For example, a stiffer film with lower transverse burst pressure properties would result from an orientation process incorporating a larger machine direction orientation draw ratio. Thus, oriented polyolefins films can be tailored to provide an appropriate burst pressure property within a preferred film thickness range. Based upon computer modeling, consistently greater dosing is believed to result from turbulence or “turning” of the delivery fluid through the passage containing the medicament. Prototype testing indicates that the burstable membranes at the opposite ends of the cartridge in the delivery devices of this invention rupture nearly simultaneously using only a modest pressure. Where the membranes are preferentially or uniaxially oriented and perpendicular, the membranes each rupture in a slit near the center along the axis of the oriented films at approximately right angles to one another. This requires the fluid, such as a gas, to turn as the fluid is rapidly transmitted through the passage, entraining the medicament and expressing the entrained medicament through the slit formed in the second membrane. It has been found by the applicant that generally perpendicular orientation of the preferentially or uniaxially oriented films oriented at right angles resulted in an emitted dose of about 97%.
In another preferred embodiment, the burstable membranes are formed of a cast polyolefin copolymer of polyethylene and polyethylene methylacrylate copolymer film having a thickness of about 0.5 mil, wherein the films are stretched taut over the passage and heat sealed or fused to the opposed ends of the cartridge. Where the burstable membranes are formed of preferentially or uniaxially oriented polyethylene film, the film preferably has a thickness of about 1 mil. However, it is believed that the burstable membranes may also be formed of other polymers including, for example, polypropylene, acetate, polycarbonate, etc., wherein the film is preferably scored or embossed to reduce the required gas rupture pressure, thus having a rupture pressure of between 1.2 and 10 atmospheres, more preferably less than 5 atmospheres and most preferab
Becton Dickinson and Company
Dawson Glenn K.
Erezo Darwin P.
West Robert E.
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