The present invention relates to a dispenser cap arrangement for enclosing a portion of a dispenser of a medicament. In particular, the present invention relates to a dispenser cap arrangement, a dispenser cap a dispenser cap closure device, a method of closing a dispenser, and a closure arrangement. The dispenser cap arrangement comprises a dispenser cap (71) comprising a hollow body having a lower open end for engaging with a body portion of a dispenser, and an upper open end for receiving a cap closure device for closing the upper open end, the upper open end comprising an engageable portion； and a cap closure device, comprising: an upper cap closure portion (101) for engaging with the upper open end of the dispenser cap to close the upper open end of the dispenser cap； a lower cap closure portion (102) for engaging with the engageable portion to secure the cap closure device to the dispenser cap； and a bistable portion (111, 112, 113) connecting the upper cap portion and the lower cap closure portion, the bistable portion being switchable between a first stable form in which the bistable portion is extended, and a second stable form in which the bistable portion is collapsed, wherein, when the bistable portion is in the second stable form, the upper cap closure portion engages with the upper open end of the dispenser cap to close the dispenser cap.
