Process for providing a filled canister for an inhaler

A process for providing a filled canister (138) for an inhaler with has not been purged prior to filling is disclosed. In particular it is a process for supplying a canister (138) and filling the canister (138) with components of a medicament, which canister (138) is suitable for use in a pressurised metered dose inhaler, preferably a breath-actuate inhaler. The process comprises providing a canister (138) that is substantially filled with air at ambient conditions and sealing the opening of the canister (138), for example with a metering valve (134). A filling device dispenses a pressurised liquid and/or gas into the sealed, air-filled canister (138) through the metering valve (134). The pressurised liquid and/or gas comprises at least a propellant. The sealed, air-filled canister (138) is substantially devoid of propellant prior to the step of dispensing the pressurised liquid and/or gas. Thereafter the sealed canister (138) is substantially filled with at least some propellant and some air. Preferably the sealed canister (138) also contains a medicament. In the art, pressure-filled canisters are purged with propellant immediately before sealing to remove the air. The present process excludes the purging step and the sealed canisters (138) contain air and no propellant prior when sealed which prevents unnecessary release of the propellant into the atmosphere.