Pore structures for reduced pressure aerosolization

Abstract

A nozzle comprising a thin, flexible substantially planar polymeric film having a plurality of pores with structures allowing for generation of an aerosol at reduced extrusion pressure is disclosed. The pores can comprise at least two sections, or steps, in which the thickness of the membrane is reduced in stepwise fashion, or the pores can be tapered. Nozzles formed comprising pores having such structures permit aerosol generation at lower extrusion pressures, thereby allowing for decreased weight of aerosolization devices, increased efficiency, increased portability and increased battery life. The pore structures also allow for the use of thicker, more easily processed polymeric films in manufacturing while having a thinner, more efficient aerosolization area. The use of decreased extrusion pressures also results in increased uniformity in aerosol generation and improved reliability of other components.

1 - 27 . (canceled) 
   
   
       28 . A method of producing a porous sheet, the method comprising:
 directing laser energy onto an entrance surface of a sheet and continuing to direct the energy until the laser has created a pore having an entrance aperture and an exit aperture having a pore entrance aperture size and a pore exit aperture size, wherein the ratio of pore entrance aperture size to pore exit aperture size is at least about 10:1, and repeating the directing a plurality of times,   wherein the laser is a yttrium aluminum garnet laser.   
   
   
       29 . The method of  claim 28 , wherein the ratio of pore entrance aperture size to pore exit aperture size is at least about 15:1. 
   
   
       30 . The method of  claim 29 , wherein the ratio of pore entrance aperture size to pore exit aperture size is at least about 25:1. 
   
   
       31 . The method of  claim 28 , wherein the yttrium aluminum garnet laser is a neodymium-yttrium aluminum garnet laser. 
   
   
       32 . The method of  claim 28 , wherein the laser is configured to provide a pulsed ultraviolet wavelength light. 
   
   
       33 . The method of  claim 32 , wherein the beam profile from the laser is radially symmetric. 
   
   
       34 . The method of  claim 33 , wherein the pores are tapered in configuration, gradually narrowing from the entrance aperture to the exit aperture. 
   
   
       35 . The method of  claim 33 , wherein each of the pores comprises two or more pore steps. 
   
   
       36 . The method of  claim 28 , wherein the laser frequency is tripled. 
   
   
       37 . The method of  claim 36 , wherein the laser frequency is tripled using a lithium triborate crystal. 
   
   
       38 . An aerosol delivery device, comprising
 a) a sheet, said sheet having a plurality of pores, wherein each of said pores has an entrance aperture size and an exit aperture size, and wherein the ratio of said entrance aperture size to said exit aperture size is at least about 10:1; and   b) a container with a flowable liquid formulation, wherein said sheet has an entrance side to which said formulation is applied.   
   
   
       39 . The device of  claim 38 , wherein the amount of liquid formulation in the container is from about 10 micro-liters to about 100 milliliters. 
   
   
       40 . The device of  claim 39 , wherein the amount of liquid is from about 10 milliliters to about 90 milliliters. 
   
   
       41 . The device of  claim 39 , wherein the amount of liquid is from about 20 microliters to about 100 microliters. 
   
   
       42 . The device of  claim 39 , wherein the sheet is rigid. 
   
   
       43 . The device of  claim 41 , wherein the sheet is a flexible membrane. 
   
   
       44 . The device of  claim 42 , wherein the container is refillable. 
   
   
       45 . The device of  claim 43 , wherein the container is disposable. 
   
   
       46 . The device of  claim 44 , wherein the formulation is applied to the entrance side of the sheet by the application of force to at least one wall of the container. 
   
   
       47 . The device of  claim 46 , wherein the force leads to a pressure inside the container of less than about 725 psi. 
   
   
       48 . The device of  claim 47 , wherein there is a low resistance filter positioned between the sheet and the container. 
   
   
       49 . The device of  claim 43 , wherein the exit apertures of the pores are surrounded by elevated areas. 
   
   
       50 . The device of  claim 48 , wherein the filter has a porosity such that the presence of the filter does not substantially increase the pressure required to generate an aerosol. 
   
   
       51 . The device of  claim 45 , wherein the container includes an opening which leads to an open channel which channel includes a peelable seal which is peeled open upon the application of a force which is created by formulation being forced from the container. 
   
   
       52 . A method of delivery of a drug to a patient comprising:
 inhaling from the device of  claim 38 .