Canisters for use in metered dose inhalers

Abstract

A canister suitable for use in metered dose inhalers and fitted with a metering valve characterised in that its walls are formed of a laminate comprising a first layer which is composed of a metal and a second layer which is composed of a strengthening material.

1 . A canister suitable for use in metered dose inhalers and fitted with a metering valve characterised in that its walls are formed of a laminate comprising a first layer which is composed of a metal and a second layer which is composed of a strengthening material.  
     
     
         2 . A canister as claimed in  claim 1  wherein the second layer of strengthening material is a plastics material selected from: polyester, polypropylene, acetonitrile-styrene copolymer, high-impact styrene, nylon or polyacetal, optionally reinforced with a material selected from carbon fibres, filaments of glass, metal, boron, aluminium silicate, calcium carbonate, talc and barium sulphate, and wherein the first metal layer is composed of a material selected from aluminium and steel and characterised in that the first metal layer forms the internal surface of the canister and is optionally coated with one or more coating layers and an adhesive layer is optionally used between the plastics material layer and the first metal layer.  
     
     
         3 . A canister as claimed in  claim 1  wherein the second layer of strengthening material is a plastics material selected from: polyester, polypropylene, acetonitrile-styrene copolymer, high-impact styrene, nylon or polyacetal optionally reinforced with material selected from carbon fibres, filaments of glass, metal, boron, aluminium silicate, calcium carbonate, talc and barium sulphate, and wherein the second layer is optionally coated with one or more coating layers and the first metal layer is composed of a material selected from aluminium and steel and characterised in that the first metal layer forms the external surface of the canister and is optionally coated with one or more coating layers and an adhesive layer is optionally used between the plastics material layer and the first metal layer.  
     
     
         4 . A canister according to  claim 2  or  claim 3  wherein the plastics material is reinforced.  
     
     
         5 . A canister according to  claim 4  wherein the plastics material is reinforced with a material selected from carbon fibres and metal.  
     
     
         6 . A canister according to  claim 1  characterised in that its walls are formed of a laminate wherein the laminate comprises a first metal layer of material forming the external surface of the canister selected from the list of metals consisting of: aluminium, brass, copper, chromium, iron, tin and steel, optionally coated with one or more coating layers, and a second layer of material selected from the list of strengthening materials consisting of aluminium, brass, copper, chromium, chromium oxide, iron, tin and steel, optionally coated with one or more coating layers.  
     
     
         7 . A canister according to  claim 1  characterised in that its walls are formed of a laminate wherein the laminate comprises a first metal layer of material forming the internal surface of the canister selected from the list of metals consisting of: aluminium, brass, copper, chromium, iron, tin and steel, optionally coated with one or more coating layers and a second layer of material selected from the list of strengthening materials consisting of aluminium, brass, copper, chromium, chromium oxide, iron, tin and steel, optionally coated with one or more coating layers.  
     
     
         8 . A canister according to  claims 1  to  7  wherein the first metal layer is aluminium or stainless steel.  
     
     
         9 . A canister according to  claim 8  wherein the first metal layer is aluminium.  
     
     
         10 . A canister according to any one of  claims 1  to  9  wherein canister is formed from a laminate comprising a layer of steel sandwiched between two layers of aluminium and optionally the internal and/or external aluminium walls are provided with one or more coating layers.  
     
     
         11 . A canister according to any one of  claims 1  to  10  containing a formulation comprising medicament and hydrofluoroalkane propellant.  
     
     
         12 . A canister according to  claim 11  wherein the propellant is selected from 1,1,1,2-tetrafluoroethane, 1,1,1,2,3,3,3-heptafluoro-n-propane and mixtures thereof.  
     
     
         13 . A canister according to  claim 12  wherein the propellant is 1,1,1,2-tetrafluoroethane.  
     
     
         14 . A canister according to any one of  claims 9  to  13  wherein the formulation is a suspension formulation free of all excipients besides propellant and the particulate drug.  
     
     
         15 . A canister according to any one of  claims 11  to  14  wherein the medicament is selected from fluticasone propionate, beclomethasone dipropionate, salmeterol, albuterol and salts or solvates thereof and mixtures thereof.  
     
     
         16 . A canister according to  claim 15  wherein the medicament is fluticasone propionate in combination with salmeterol xinafoate.