Abstract: An in vitro intestinal drug disposition device (1) comprises a donor chamber (2) for a donor solution and having a bottom end (18) and a top end (19). The device (1) also comprises a receiver chamber (3) for an absorption solution and an absorption membrane (4) arranged in between and separating the chambers (2, 3). A first side (5) of the absorption membrane (4) is to be in contact with the donor solution and a second side (6) of the absorption membrane (4) is to be in contact with the absorption solution. A ratio of an internal volume of the donor chamber (2) to an area of the first membrane side (5) is equal to or smaller than 3 ml/cm2. A cross-sectional area of the donor chamber (2) at the bottom end (18) is larger than a cross-sectional area of the donor chamber (2) at the top end (19).