Pharmaceutical aerosol composition containing HFA 227 and HFA 134a

Abstract

In a solution composition for use in an aerosol inhaler which comprises an active material, a propellant containing a hydrofluoroalkane, a cosolvent and optionally a low volatility m compound the use of a mixture of HFA 134a and HFA 227 allows to modulate the mass median aerodynamic diameter (MMAD) of the aerosol particles on actuation of the inhaler to target specific regions of the respiratory tract. Moreover the fine particle dose (FPD) of the active ingredient in the composition increases by reducing the metering chamber volume.

1 . A composition in form of solution for use in an aerosol inhaler, the composition comprising an active material, a propellant containing a hydrofluoroalkane (HFA), a cosolvent, optionally a low volatility component characterized in that the propellant consists of a mixture of HFA 227 and HFA 134a.  
     
     
         2 . A composition according to  claim 1 , wherein the ratio of HFA 227/HFA 134a ranges from 10:90 to 90:10.  
     
     
         3 . A composition according to  claim 1  or  2 , wherein the low volatility component has a vapour pressure at 25° C. lower than 0.1 kPa.  
     
     
         4 . A composition according to  claim 3 , wherein the low volatility component has a vapour pressure at 25° C. lower than 0.05 kPa.  
     
     
         5 . A composition according to any preceding claim, wherein the cosolvent has' a vapour pressure at 25° C. lower than 3 kPa.  
     
     
         6 . A composition according to any preceding claim, wherein the cosolvent has a vapour pressure at 25° C. lower than 5 kPa.  
     
     
         7 . A composition according to any preceding claim, wherein the cosolvent is an alcohol.  
     
     
         8 . A composition according to any preceding claim, wherein the low volatility component includes a glycol, oleic acid or isopropyl myristate.  
     
     
         9 . A composition according to any preceding claim, wherein the composition includes not more than 20% by weight of the low volatility component.  
     
     
         10 . A composition according to any preceding claim, wherein the composition includes at least 0.2% by weight of the low volatility component.  
     
     
         11 . A composition according to any preceding claim, the composition being such that, on actuation of the aerosol inhaler in use, the MMAD of the aerosol particles is not less than 2 μm.  
     
     
         12 . An aerosol inhaler containing a solution composition comprising an active material, a propellant containing one or more hydrofluoroalkane, a cosolvent and optionally a low volatility component wherein the particle MMAD is greater than 2 μm and the fine particle dose (<4.7 μm) is >30%.  
     
     
         13 . An aerosol inhaler according to  claim 12  wherein the particle MMAD is greater than 2 μm and the fine particle dose (<4.7 μm) is >40%.  
     
     
         14 . An aerosol inhaler according to claims  12  and  13  wherein the particle MMAD is greater than 0.2 μm and the fine particle dose. (<4.7 μm) is >50%.  
     
     
         15 . An aerosol inhaler according to  claims 12  to  14  having a chamber volume ranging from 25 to 50 μl yielding an increase of FPD compared to inhalers having chamber volumes larger than 50 μl.  
     
     
         16 . An aerosol inhaler according to  claims 12  to  15  containing the compositions of claims  1 - 11 .  
     
     
         17 . An aerosol inhaler according to  claims 12  to  16  having part or all of the internal surfaces consisting of stainless steel, anodised aluminium or lined with an inert organic coating.  
     
     
         18 . A delivery system for the administration of drugs to the lung consisting of aerosol drug solution in a mixture of 134a and 227 HFA propellants, a cosolvent and optionally a low volatility component, in an aerosol inhaler having a chamber volume ranging from 25 to 50 μl.