Methods and devices for delivering a dose, such as a medicament, for inhalation. A dose may be stored by a delivery device and dispersed and delivered in a metered fashion to a subject, such as by the subject inhaling via a mouthpiece of the delivery device. One or more chambers of the device may have a toroidal shape and may be arranged to be selectively opened for fluid communication with a flow path of the delivery device, such as by sliding the chamber relative to a portion of the flow path. The flow path may include a restriction that permits air to bypass the chamber, and/or the chamber may be arranged so that fluid entering the chamber interacts with fluid exiting the chamber so as to enhance dispersion of the dose.