Dry powder inhalers

A dry powder inhalation device comprising:

• a chamber;
• a patient port in communication with the chamber;
• an elongate carrier preloaded with a plurality of doses of finely divided powder comprising a biologically active substance, wherein the elongate carrier does not comprise a lid component, said powder being releasably retained on a surface of the carrier;
• an advancement mechanism for advancing a portion of the carrier to within the chamber so that the powder associated with an advanced area of the carrier can be released from the carrier for inhalation by the patient through the patient port;
• and
• a first clamping system and a second clamping system, wherein the first and second clamping systems are configured and arranged such that they are moved into a clamping configuration at least prior to release of the powder associated with the area of the carrier, so that the area of the carrier will be clamped between the first and the second clamping systems during release of the powder associated with the area of the carrier, and wherein at least one of the first and second clamping systems comprises a seal.