INHALERS

1 . A dry powder inhaler comprising at least one medicament reservoir containing a bulk quantity of a powdered medicament, and a metering mechanism by which unit doses of said medicament can be dispensed from the medicament reservoir for inhalation by a user of the inhaler, wherein said at least one medicament reservoir is formed from polyester material.

2 . An inhaler as claimed in claim 1 , wherein the polyester material used in the manufacture of the medicament reservoir is polyethylene terephthalate (PET) or a related material.

3 . An inhaler as claimed in claim 2 , wherein the polyester material is glycol-modified PET.

4 . An inhaler as claimed in claim 3 , wherein the glycol-modified PET is a form of PET that contains cyclohexane dimethanol residues in place of ethylene glycol units.

5 . An inhaler as claimed in claim 1 , wherein the polyester material is the glycol-modified PET sold under the trade name EASTAR MN200.

6 . An inhaler as claimed in claim 1 , wherein the polyester material is the glycol-modified PET sold under the trade name EASTAR MN005.

7 . An inhaler as claimed in claim 2 , wherein the polyester material contains isophthalic acid (benzene-1,3-dicarboxylic acid) and/or phthalic acid (benzene-1,2-dicarboxylic acid) residues in place of some of the terephthalic acid (benzene-1,4-dicarboxylic acid) residues.

8 . An inhaler as claimed in claim 1 , wherein the polyester material is polycarbonate or polybutyrate.

9 . An inhaler as claimed in claim 1 , which comprises a medicament reservoir and a metering member that closes an opening in the reservoir and which is adapted to transfer a unit dose of medicament from the reservoir to a position from which the dose of medicament can be inhaled by the user of the device.

10 . An inhaler as claimed in claim 9 , which comprises a rotatable metering member that is formed with a series of cups that are sized such that they can hold a unit dose of the medicament, such that rotation of the metering member moves a cup from a first position in which it fills with medicament to a second position, external to the reservoir, at which the cup is positioned adjacent to the path of an airflow through the device, by means of which the dose can be entrained in the airflow and inhaled.

11 . An inhaler as claimed in claim 10 , wherein the rotatable metering member takes form of a frustoconical member that is urged into close engagement with the lower part of the medicament reservoir.

12 . An inhaler as claimed in claim 9 , wherein the metering member moves in a linear or reciprocating manner.

13 . An inhaler as claimed in claim 9 , wherein the metering member is formed from polyester material.

14 . An inhaler as claimed in claim 13 , wherein the medicament reservoir is formed from glycol-modified PET sold under the trade name EASTAR MN200, and the metering member is formed from glycol-modified PET sold under the trade name EASTAR MN005.

15 . A method of reducing the ingress of moisture into the medicament reservoir of a dry powder inhaler, which method comprises forming the medicament reservoir from polyester material.

16 . A method of use of polyester material in the manufacture of the medicament reservoir of a dry powder inhaler comprising forming the medicament reservoir of a dry powder inhaler from polyester material.

17 . A method of improving the fine particle fraction of medicament dispensed from a dry powder inhaler comprising a medicament reservoir containing a bulk quantity of a powdered medicament, which method comprises forming the medicament reservoir from polyester material.

18 . A method as claimed in claim 15 , wherein the inhaler is formed from polyethylene terephthalate or a related material.

19 . A method as claimed in claim 16 , wherein the inhaler is formed from polyethylene terephthalate or a related material.

20 . A method as claimed in claim 17 , wherein the inhaler is formed from polyethylene terephthalate or a related material.