Metered dose valves and dispensers

1. A metered dose valve comprising an interior conduit, a metering chamber and at least one porous, fluid permeable, particulate semi-permeable body, said at least one porous body being positioned within a region of the interior conduit of the valve to hold medicament particles substantially uniformly dispersed within a volume of the porous body; wherein the porous body is permeable to at least particulates having a particle size of 250 microns or less and the porous body is impermeable to at least particulates having a particle size of 2 mm or more, and wherein the valve is a medicament-dispensing pressurized meter dose dispenser valve that dispenses a metered dose of an aerosol formulation comprising the medicament particles suspended in liquefied propellant.

2. A valve according to claim 1 , wherein the at least one porous body is positioned within an internal chamber or within an internal channel within the valve leading to the metering chamber or within both said internal chamber and channel.

3. A valve according to claim 2 , wherein the at least one porous body is positioned within an internal chamber, and wherein the internal chamber is the metering chamber or a pre-metering chamber.

4. A valve according to claim 1 , wherein the valve comprises an internal channel leading into the metering chamber, wherein the at least one porous body is positioned within said internal channel.

5. A valve according to claim 4 , wherein the valve comprises at least two porous bodies, wherein at least one porous body is positioned within said internal channel and at least one porous body is positioned within the metering chamber.

6. A valve according to claim 1 , wherein the valve comprises a pre-metering chamber and the at least one porous body is positioned within the pre-metering chamber.

7. A valve according to claim 6 , wherein the at least one porous body is positioned within the pre-metering chamber directly adjacent to the outlet(s) of the pre-metering chamber leading to the metering chamber—or the entrance(s) of a passageway from the pre-metering chamber to the metering chamber.

8. A valve according to claim 6 , wherein the valve comprises an internal channel between the pre-metering chamber and the metering chamber and the at least one porous body is positioned within the pre-metering chamber and the internal channel.

9. A valve according to claim 8 , wherein the valve comprises at least two porous bodies, wherein at least one porous body is positioned within the pre-metering chamber and at least one porous body is positioned within the internal channel.

10. A valve according to claim 6 , wherein the valve comprises at least one additional porous body, said at least one additional porous body being positioned within the metering chamber.

11. A valve according to claim 1 , wherein the porous body has a plurality of pores in particular 10 or more pores.

12. A valve according to claim- 1 , wherein the porous body has a relative density of 50% or less.

13. A valve according to claim 1 , wherein the porous body comprises a material having a filamentous, fibrous and/or ligamentous structure.

14. A valve according to claim 1 , wherein the porous body comprises a material having a relative density of 50% or less.

15. A valve according to claim 1 , wherein the porous body comprises a material providing tortuous paths for passage of aerosol formulation.

16. A valve according to claim 1 , wherein the porous body comprises a material selected from the group consisting of nonwovens, open-cell foams and reticulate open-cell foams.

17. A pressurized metered dose dispenser for dispensing a metered dose of an aerosol formulation comprising particles of a medicament suspended in liquefied propellant, optionally in combination with one or more excipients, the dispenser comprising an aerosol container equipped with a metered dose valve according to claim 1 .