Abstract: A capsule device with thermally-stable specific gravity control is disclosed. The capsule device comprises a capsule unit adapted to be swallowable by a human subject and an inflatable balloon comprising a thermally-stable effervescent formulation inside the inflatable balloon, where the thermally-stable effervescent formulation has a particular particle size between a first mesh size and a second mesh size, and the inflatable balloon is attached to the capsule unit. After the capsule unit with the inflatable balloon attached is swallowed, the inflatable balloon starts to inflate so as to lower specific gravity of a combination of the capsule unit and the inflatable balloon when the inflatable balloon is exposed to body fluid and the body fluid gets in touch with the thermally-stable effervescent formulation inside the inflatable balloon.