Apparatus and method for generating and concentrating fine particle aerosols

Abstract

A system and a method for generating a respirable dry powder aerosol from a liquid solution or liquid suspension at a respirable dry powder aerosol volume flow. A liquid aerosol generating nozzle generates from the liquid solution or liquid suspension a liquid aerosol that is diluted by dilution gas and dried in a cylindrical evaporation chamber to generate a dry powder aerosol. The system and method include heliox as a gas, specifically dilution gas, for enhancing the drying process in the cylindrical evaporation chamber, but also as a nozzle gas for enhancing generating the liquid aerosol from the liquid solution or liquid suspension.

What is claimed is: 
     
         1 . An aerosol generating system for generating a respirable dry powder aerosol from a liquid solution or liquid suspension, comprising:
 a liquid aerosol generating nozzle having a nozzle input end designed to receive the liquid solution or liquid suspension, and having a nozzle heliox supply designed to receive nozzle heliox, the liquid aerosol generating nozzle further having a nozzle output end for outputting a liquid aerosol suspended in the nozzle heliox; and   a cylindrical evaporation chamber having a cylindrical evaporation chamber input end that is connected to the nozzle output end and connected to a dilution heliox supply for receiving both the liquid aerosol suspended in the nozzle heliox and for receiving the dilution heliox, and the cylindrical evaporation chamber having a cylindrical evaporation chamber output end outputting a first intermediate dry powder aerosol at a first intermediate dry powder aerosol volume flow and a first intermediate dry powder aerosol particle concentration.   
     
     
         2 . The system according to  claim 1  wherein the first intermediate dry powder aerosol volume flow is between 80 and 200 l/min. 
     
     
         3 . The system according to  claim 1  wherein the liquid solution or liquid suspension contains a surfactant. 
     
     
         4 . The system according to  claim 1  wherein the system is designed to output from the cylindrical evaporation chamber the first intermediate dry powder aerosol having fine particles of a size of 1.5-4 μm MMAD suspended in gas. 
     
     
         5 . The system according to  claim 1  wherein the system is designed to aerosolize the liquid solution or liquid suspension having a liquid solution or liquid suspension viscosity of 4 to 39 cSt. 
     
     
         6 . The system according to  claim 1  wherein the nozzle heliox has a nozzle heliox pressure between 207 and 414 kPa. 
     
     
         7 . The system according to  claim 1  further comprising a counter flow tube, an infrared radiation source, a reflector, and an aerosol collection cone. 
     
     
         8 . The system according to  claim 1  wherein the system is designed to receive the liquid solution or liquid suspension at a liquid solution or liquid suspension volume flow of 0.1-3 ml/min, delivering a medication at a medication mass flow rate of at least 150 mg/min at 3 ml/min in form of the solid particles having a dry powder aerosol mass median aerodynamic diameter (MMAD) of 3 μm or less. 
     
     
         9 . The system according to  claim 8  wherein the system is designed to receive the liquid solution or liquid suspension at a liquid solution or suspension viscosity exceeding 4 cSt. 
     
     
         10 . The system according to  claim 1  further comprising an aerosol concentrator or a series of aerosol concentrators having an aerosol concentrator input end that is connected to the cylindrical evaporation chamber output end, and an aerosol concentrator output end outputting a second intermediate dry powder aerosol at a second intermediate dry powder aerosol volume flow and a second intermediate dry powder aerosol particle concentration, the second intermediate dry powder aerosol volume flow being lower than the first intermediate dry powder aerosol volume flow and the second intermediate dry powder aerosol particle concentration being higher than the first intermediate dry powder aerosol particle concentration. 
     
     
         11 . A method for generating a respirable dry powder aerosol from a liquid solution or liquid suspension, comprising:
 feeding liquid solution or liquid suspension and nozzle heliox into a liquid aerosol generating nozzle;   outputting from the liquid aerosol generating nozzle a liquid aerosol suspended in the nozzle heliox into a cylindrical evaporation chamber;   feeding dilution gas into the cylindrical evaporation chamber; and   outputting from the cylindrical evaporation chamber a first intermediate dry powder aerosol having fine dry powder particles that allow respirable particles containing a medically active agent and are suspended in gas at a first intermediate dry powder aerosol volume flow and a first intermediate dry powder aerosol particle concentration.   
     
     
         12 . The method according to  claim 11  further comprising generating the first intermediate dry powder aerosol volume flow at between 80 and 200 l/min. 
     
     
         13 . The method according to  claim 11  further comprising providing a surfactant as a constituent of the liquid solution or liquid suspension. 
     
     
         14 . The method according to  claim 11  further comprising outputting from the cylindrical evaporation chamber the first intermediate dry powder aerosol at a fine particles of a size of 1.5-4 μm MMAD suspended in gas. 
     
     
         15 . The method according to  claim 11  further comprising aerosolizing the liquid solution or liquid suspension having a liquid solution or liquid suspension viscosity of 4 to 39 cSt. 
     
     
         16 . The method according to  claim 11  further comprising supplying the nozzle heliox at a nozzle heliox pressure between 207 and 414 kPa. 
     
     
         17 . The method according to  claim 11  further comprising providing a counter flow tube, an infrared radiation source, a reflector, and an aerosol collection cone. 
     
     
         18 . The method according to  claim 11  further comprising supplying the liquid solution or liquid suspension at a liquid solution or liquid suspension volume flow of 0.1-3 ml/min, delivering a medication at a medication mass flow rate of at least 150 mg/min at 3 ml/min in form of the solid particles having a dry powder aerosol mass median aerodynamic diameter (MMAD) of 3 μm or less. 
     
     
         19 . The method according to  claim 11  further comprising supplying the liquid solution or liquid suspension at a liquid solution or suspension viscosity exceeding 4 cSt. 
     
     
         20 . The method according to  claim 11  further comprising feeding the first intermediate dry powder aerosol into an aerosol concentrator or a series of aerosol concentrators having an aerosol concentrator input end that is connected to the cylindrical evaporation chamber output end, and an aerosol concentrator output end outputting a second intermediate dry powder aerosol at a second intermediate dry powder aerosol volume flow and a second intermediate dry powder aerosol particle concentration, the second intermediate dry powder aerosol volume flow being lower than the first intermediate dry powder aerosol volume flow and the second intermediate dry powder aerosol particle concentration being higher than the first intermediate dry powder aerosol particle concentration.