Given that airway diameters decrease by almost two orders of magnitude between the trachea and the peripheral, gas-exchange regions of the lung, for a given particle length the interception mechanism will become increasingly significant moving deeper into the lung. Deposition by interception depends on the ratio between particle length and airway diameter, as well as on the orientation of a particle as it travels through an airway. In considering the inhalation of elongated, high aspect ratio particles, an additional deposition mechanism must be taken into account, this being the interception of the tip of a particle with an airway wall. In a given region of the respiratory tract, the probability of deposition due to these mechanisms is dependant on particle size and density, as well as on the airway geometry and flow patterns within that region. For compact, approximately spherical, aerosol particles, deposition primarily occurs through inertial impaction, gravitational sedimentation, or Brownian diffusion onto airway walls.
Respiratory tract deposition of inhaled pharmaceutical aerosols has been studied extensively due to its importance in determining drug dosages delivered to the lung.
Vmd fieldlines max length generator#
The apparatus of claim 15 in which the magnetic field generator is configured to provide an oscillating or rotating magnetic field.ĮNHANCED DRUG DELIVERY WITH ORIENTABLE PARTICLES The apparatus of claim 14 in which the magnetic field generator is configured to provide a time varying field.ġ6. Apparatus for targeted delivery of drug to the lung, the apparatus comprising: a drug delivery device containing magnetically orientable drug particles and a magnetic field generator.ġ5. The method of claim 11 in which the magnetic field is a rotating magnetic field.ġ4. The method of claim 11 in which the magnetic field is an oscillating field.ġ3. The method of claim 9 or 10 in which the magnetic field is a time varying magnetic field.ġ2. The method of claim 9 in which the magnetic field is generated by a solenoid and turned on at a chosen time.ġ1. The method of claim 7 or 8 in which the orientation of the particles is altered by a magnetic field external to the lung.ġ0. The method of claim 7 in which the particles comprise particles of any one of claims 1-6.ĩ. A method for delivery of a drug to a lung, the method comprising the steps of: directing particles comprising a drug into passageways of the lung and altering the orientation of the particles when the particles arrive at a selected location in the lung.Ĩ. The particle of any one of claim 2 - claim 5 in which the drug is contained in a drug particle attached to a surface of the particle.ħ. The particle of claim 1 or 2 in which the particle is acicular.Ħ. The particle of claim 3 in which the particle has a length to width ratio greater than 3.ĥ. The particle of claim 1 or 2 in which the particle has a length greater than its maximum width.Ĥ. The particle of claim 1 in which the orienting element is a magnetically susceptible material.ģ. A particle comprising a combination of orienting element and drug, and the orienting element is distributed in the particle to provide a torque on the particle in response to an external field.Ģ.
311, 2007, pages 372 - 375ĭOBSON, J.: "Magnetic nanoparticles for drug delivery", DRUG DEVELOPMENT RESEARCH, vol. WU ET AL.: "Effects of external magnetic field on biodistribution of nanoparticles: a histological study", JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, vol. MARTIN ET AL.: "Alignment of magnetite-loaded high aspect ratio aerosol drug particles with magnetic field", AEROSOL SCIENCE AND TECHNOLOGY, vol. MARTIN ET AL.: "Enhanced deposition of high aspect ratio aerosols in small airway bifurcations using magnetic field alignment", JOURNAL OF AEROSOL SCIENCE, vol. 311, April 2007 (), pages 367 - 371ĬHAN ET AL.: "Aerodynamic properties of elongated particles of cromoglycic acid", JOURNAL OF AEROSOL SCIENCE, vol. TAKEDA, SI ET AL.: "Development of magnetically targeted drug delivery system using superconducting magnet", JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, vol. 2, August 2007 (), pages 495 - 499ĪLLY, J ET AL.: "Magnetic targeting of aerosol particles for cancer therapy", JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, vol. DAMES, P ET AL.: "Targeted delivery of magnetic aerosol droplets to the lung", NATURE NANOTECHNOLOGY, vol.
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