NZ544519A - A nebulizer including an aerodynamically profiled nozzle - Google Patents

Abstract

A nebulizer including an aerodynamically profiled nozzle formed from a hypodermic needle curved and splayed into a crook shape.

Description

" HAvS\<=\ Patents Act 1953 Complete Specification intellectual property office of n.2. 3 1 AUG 2007 RECEIVED A LOW PRESSURE MICROMIST NEBULIZER FOR SMALL VOLUME DOSIMETRIC AEROSOL GENERATION I MARK PHILIP BEST of 2 Pateke PI.,Bromley, Christchurch New Zealand, a New Zealand Citizen HEREBY declare the invention for which I pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement- 1 Nebulizer designs for generation of aerosol micromists are of interest for increased dispensing efficiency and favourable deep lung administration of inhaled pharmaceuticals and dispersal of very small volume liquids for misting and spraying applications.

A nebulizer unit is described which is driven by low pressure pneumatic means and a mist produced of one micron diameter from less than 0.5ml of feed solution and a lag volume of less than 0.05ml contributing to it's efficiency and lending itself to nebulization and respiratory delivery of expensive and researched agents such as those produced by pharmaceutical chemistry and biotechnology.

A low pressure (8-101/min)domicillary air pump or cylinder widely found in routine respiratory health care situations and misting applications is used to drive the device. A number of driving gases other than air are useful and agents in the anaesthetic situation,operating theatres,intensive care and clinics with a slow moving stream of mist being produced for easy patient administration. Nebulizers are of widespread interest in respiratory medicine for pneumonia,asthma,cystic fibrosis,emphysema,cancer and dosimetric drug delivery eg antibiotics and nicotine where these powerful agents are required in the H5N1 bird flu pandemic and smoking 2 intellectual property office of n.z. 31 AUG 200? RECEIVED cessation situations to avoid toxicity. (Byron PR and Patton JS Journal of Aerosol Medicine Vol 7 No 11994 pp49-75) It is well known that inhalation of coarse aerosol mists results in impaction at the back of the large airways and adverse localized reactions such as coughing and a sore throat result, also medications will miss their target from the adverse delivery of the larger droplets. Nebulizers available at this time vary considerably in their operation,output,efficiency,size and utility. Some rely on ultasonic generation known to be harsh on sensitive proteins with heat generation and cavitation (Waldman 3 et al Chemical breakdown Technetium 99m DTPA during nebulization.) whilst others utilize bulky sedimentation chambers, feed conduit systems, baffles, inefficient dosage delivery especially with small volumes and are difficult to breath from.(McArthur AW From Proceedings of the Third World Congress of Nuclear Medicine and Biology Paris France Ed C Raynaud Pergamon Press pp 2569-2572 1982) The most widely used aiijet nebulizer is based on an internal turret design utilizing a vertical air supply from the bottom and is capable of quickly generating a dense fog in a bowl chamber with baffles and utilizes a 3D fountain effect and swirling to create it's mist and is widely used effectively in airways humidification and can hold a large volume. 3 intellectual property office of n.z. 31 AUG 2007 RECEIVED Particle size is characteristically large requiring baffles and size separation modification is described in the art. The turret unit is relatively bulky,with an operating volume and system loss and produces a dense static mist which the patient also adversely experiences requiring more breathing effort and pneumatic loss with regard to drug delivery this being important in an acute asthma attack.

A nebulizer described herein utilizes a configured bluff aerodynamic nozzle formed from hypodermic needle curved and splayed into a shallow crook shape to create in use a negative pressure wake effect with airflow around it and containing slot opening internal feed within the nozzle reacting and suctioning with this air sourced from an inlet barb and ducted into the compact airstream chamber within a housing body thus powered by the low pressure air supply. The nozzle comprising a standard needle whose end has been narrowed and flattened to form a slot shaped opening, the end of the needle also being bent so that the needle forms, in profile, the shallow crook shape to form a smooth aerodynamic bluff body around and over which a stream of air may pass,while medicament fluid flows upwards through the needle from conduit connected to the tapered reservoir and out through the slot opening producing in combination suctioning and 4 intellectual property office of n.z. 31 AUG 2007 RECEIVED dispersal into the generated airstream within the chamber.

Constructed with no moving paits the disclosed nebulizer unit relies on mist generation from an aerodynamic nozzle with filamentous feed from within it's internal slot orifice and staged separation path to produce the mist within the small narrow cylindrical chamber and it's downstream aerodynamic flowfield.

The moving stream of mist is subject to angular momentum separation and extraction of larger droplets within the 2-3mm radius cylindrical housing chamber with ground effect and reflection and interception as it is emitted and entrained from the nozzle from the device for administration and recycling. Structural components consist of a housing containing a conduit,the aerodynamic nozzle,flowfield chamber and fluid reservoir which are readily assembled. A holder with a negative structural impression as a base is also disclosed for accomadating the device for dosimetric weighing and storage. Fig 1. The nebulizer device in a cutaway lateral view showing housing,nozzle placement in flow aerosolization chamber the reservoir,conduit and emission and exit pathway out the top l.Reservoir 2.Screws tightening union of components 3.Housing top section 4.Barb gas connection 5.Aerodynamically profiled feed aerosolization nozzle in the chamber 6.Housing bottom section intellectual property office of n.z 3 1 m 2007 RECEIVED 7.Feed conduit from reservoir for fluidic access.

The mechanism of aerosolization within the chamber relies on airflow over the bluff aerodynamic shaped nozzle which is internally fluidly linked with the feed conduit to the reservoir. The aerodynamic shaped nozzle directs the airflow over if s surface and into it's generated vortex which extracts the fluid in filaments from within the hypodermic derived conduit connected to the reservoir. The nozzle is internally shaped in the shadow side as a slot within the bluff body profiled to allow filamentous feeding of the fluid from the reservoir conduit into the energized rotary vortex. This vortex created by the aerodynamics provided in the chamber imparts angular momentum on the moving coarse mist which allows separation and extraction by interception and contact on the chamber system surfaces recycling this liquid back into the feed reservoir and participation back into the nebulization process. The near wake effect generated by the aerofoil doublet airflow utilizing ground effect and aximetric rotation generated by the energized circulatory vortex is produced by the bluff nozzle body in intimate vacuous proximity to the internal feed. 6 intellectual property office of m.z. 31 AUG 2007 RECEIVED Size analysis utilizing US Patent No 4676973 shows particle size analysis with aerosol droplet diameter to be about one micron. ( Fig 2. Aerosol Droplet Size Distribution showing mist particle dimension com position/measurement producing one micron size particles.) Micromist aerosols remain suspended in the air for longer following aircurrents and brownian like motion and random diffusion and in the absence of air currents such in shipping containers as a fumigation procedure, settling eventually with gravity.

The nebulization rate of the device of 0.2ml per minute and minimal lag of 0.05ml allows small volume efficient handling and utilization of potent agents such as anticancer agents and radionuclides with compact shielding and biotechnology derived proteins are of interest in lung cancer delivery and specificity targets, eg monoclonal antibodies.

(Best M Method of Diagnosing Lung Abnormalities Using Radiolabelled Agents. US Patent 4,676,973 1987). Accurate measurement of dispensed output can be achieved by detachment and weighing the unit and base and use in dosimetric determination is able to be recorded and logged. With a horizontal air supply the unit can be detached and stored remotely without leakage and gravimetric weighing on a four figure balance. 7 [Intellectual property office of n.z 3 i A'J3 2® RECEIVED The nebulizer components are of surgical grade quality and with a compatibility and audit trail for Good Manufacturing Practice (GMP).

These are sourced from hypodermic needle intravenous inline surgical accessory suppliers and are readily available commercially at low cost. A housing body for the nebulizer consisting of the union of two machined sections to form the aerosolization chamber and allow fitting in of the nozzle and conduit and the tapered feed reservoir in the form of a centrifuge tube,and barb fitted. Fastening together of the two nebulizer body pieces is achieved with four screws countersunk and tapped. The two housing body sections can be each made from a solid plastic disc eg Lexan 1 cm thick which is machined in an autolathe from sheet or moulded. The two disc pieces are clamped together and the machining is done as the single unit and split at the end of the automated process to produce three drilled ducting holes in the housing body. The union of the two housing body pieces forms the aerosolization chamber and barb connection.(Fig 3.Housing and ducting with union of body pieces. Section view,inverse plan of the nebulizer body showing ducting and machining and shape construction.)(Fig 4.Aerodynamic nozzle from a lateral view and from downstream, positioned within the aerosolization chamber to facilitate filamentous release of liquid into airstream. 8 intellectual property office of n.z 3 ! AOS 2007 RECEIVED Nozzle profile and position in the aerosolization flowfield chamber.) The nozzle is formed by bending and splaying a hypodermic needle or tube into the microscopic aerodynamic wing shape and internal feed slot all done on a jig/jewelers clamp. Adjustment variants created by altering inclination profile of nozzle pitch angle of between twenty and fourty degrees and internal throat shape of a slot with ends to create filaments of solutions in production of various desired particle sized mists released. Size separation occurs downstream at two further bifurcations with the moving stream. The mist stream is first turned ninety degrees by the reservoir tube and again as emitted out of top with large droplets coalescing and dropping back into the reservoir for recycling. (Fig 5. Aerodynamic profile, airflow and mechanism of aerosolization) The cap on the nebulizer reservoir can be kept on to prevent evaporation whilst not in use in it's base (Fig 6. Base holder for the nebulizer) or standard valve set administration gear added as needed for a particular patient. 9 intellectual property office of n.z 3 1 AOS 2007 RECEIVED With no moving parts,self cooling,no electrical flashpoints it is safe to operate in volatile environments such as operating theatres with sterilizing solutions and anaesthetic vapours in the atmosphere. Sourced compatible componentry of surgical hypodermic needle and conduit link the reservoir and it's microscale guage contributes to minimal lag volume specifications and the nebulizer being cheap and simple to produce has wide application.

LIST OF IMAGES Fig l.Nebulizer from a lateral view showing aerodynamic nozzle in the aerosolization chamber,housing body,reservoir,conduit and emission and exit pathway out the top.

Fig 2.Aerosol Droplet Size Distribution showing mist particle dimension composition/measurement producing one micron size particles. Fig 3.Section view,inverse plan of the nebulizer body showing ducting and machining and shape construction.

Fig 4.Aerodynamic nozzle from a lateral view and from downstream positioned within the aerosolization chamber to facilitate filamentous release of liquid into airstream. intellectual property OFFICE OF N.z 3 1 AU3 2007 RECEIVED Fig 5.Aerodynamic profile, airflow and mechanism of aerosolization within the nebulizer housing body around nozzle.

Fig 6. Base holder for the nebulizer to allow storage,remote preparation and weighing of the unit to determine dose nebulized.

REFERENCES CITED 1.Byron PR and Patton JS Journal of Aerosol Medicine Vol 7 No 11994 pp 49-75 2.McArthur AW From Proceedings of the Third World Congress of Nuclear Medicine and Biology Paris France Ed C Raynaud Pergamon Press pp 2569-2572 1982 3.Best M Method of Diagnosing Lung Abnormalities Using Radiolabeled Agents. US Patent 4676973 4.Best M Calculating Aerosol Droplets Dimensions US Patent No 4770052 .Waldman J et al Chemical breakdown Technetium 99m DTPA during nebulization.

Journal of Nuclear Medicine 28 pp 378-3921987 6.Rustad A et al Small Volume Nebulizer US Patent Application No 20040031485 11 intellectual property office of m.z 31 AUS 2007 RECEIVED

Claims (8)

What I claim is:

1. A nebulizer utilizing an aerodynamically profiled nozzle containing an internal slot throat feed positioned in a compact airflow chamber comprising: a pylon support as a connecting conduit and a configured bluff surface presenting aerodynamic nozzle; the nozzle being formed from hypodermic needle curved and splayed to in use form a negative pressure effect creating a microvortex reflecting wake and a slot like internal feed having an airflow inlet set in a supporting housing body with drilled ducting holes linking via tubing connection with the airflow chamber and a tapered fluid reservoir.

2. A nebulizer as claimed in claim 1 with a pylon support and fluidic conduit combined into an aerodynamic shaped microscopic nozzle utilizing generated aximetric airflow rotation and ground effect reflection produced from a feed input connected to a tapered reservoir which economically reduces the fluid feed quantity with a recycling pathway for aerosol dispensing of small volumes of fluids with the near wake formed by a split aerofoil airflow from around the pylon and nozzle.

3. A nebulizer as claimed in anyone of Claims 1 to 2 with the aerofoil nozzle set in the housing body formed from a union of two structural plastic D shaped sections resulting in a compact cylindrical linear chamber system 12 INTELLECTUAL PROPERTY OFFICE OF N.Z. 11 JUN 2008 RECEIVED which generates a microstaged flowfield sequentially separating and extracting larger aerosol droplets utilizing angular momentum from the resultant stream with low impedance for a small sized mist.

4. A nebulizer as claimed in any one of Claims 1-3. with a horizontal air/oxygen feed into a ducted barb positioned at the begining of the airflow chamber in the housing body as a moving stream low pressure aerosol mist dispenser of small volumes of fluids.

5. A nebulizer as claimed in any one of Claims 1-4. further including a base with the base acomadation consisting of a solid cylinder with a negative impression of the bottom of the nebulizer as a moving stream aerosol mist dispenser for misting and humidification applications including fumigation where measured dispensing can be accurately determined by weighing the unit in the base.

6. A nebulizer as claimed in Claim 1. capable of nebulizing small volumes typically about 0.5ml in a dosimetric fashion and with maximum system loss of less than 0.1ml.

7. A nebulizer as claimed in Claim 1. capable of nebulizing volumes down to 0.2ml in a dosimetric fashion and with system loss of less than 0.05ml. 13 INTELLECTUAL PROPERTY OFFICE OF N.Z. 1 1 JUN 2008 RECEIVED

8. A configured bluff aerodynamic nozzle formed from hypodermic needle or tube curved over about one hundred and twenty five degrees and splayed into a bluff aerodynamic crook shape with aerofoil characteristics to form in use a negative airflow pressure effect,creating a micro vortex wake, the nozzle having a slot shaped internal feed and the other end compatible with connection by catheter type conduit tubing. 14 END OF CLAIMS INTELLECTUAL PROPERTY OFFICE OF N.Z. 11 JUN 2008 RECEIVED