Lumen insertable capsule

A capsule device (100) suitable for insertion into a lumen, such as a gastrointestinal lumen, of a subject. The capsule device (100) comprises: a capsule housing (110, 120), a drug chamber (B) configured to accommodate a drug substance, the drug chamber leading to a drug outlet (190), - an actuation chamber (A), - a movable separator (160) arranged between the actuation chamber and the drug chamber, wherein movement of the movable separator expels drug substance from the drug chamber (B) through the drug outlet (190), and - a gas generator (140, 150) configured actuatable to generate pressurized gas in the actuation chamber (A) for exerting mechanical load on the moveable separator (160) to expel the drug substance. A burst gate (170) is arranged between the gas generator (140, 150) and the movable separator (160), the burst gate (170) configured to release mechanical load onto the movable separator (160) upon increase in gas pressure in the actuation chamber (A) above a threshold pressure level to thereby initiate expelling of the drug substance.