A mobile pharmacy compounding system is provided. The system includes a first module (101) having a first housing (105) defining a first inner space (103), in which at least a portion of the first inner space has a first cleanliness class. The first housing has a first opening (109) on a first wall (107) and a second opening (113) on a second wall (111). The system further includes a second module (121) having a second housing (125) defining a second inner space (123) of a second cleanliness class, wherein the first cleanliness class is higher than the second cleanliness class. The second module has a third opening (129) on a third wall (127) and a fourth opening (133) on a fourth wall (131). One of the first opening and the second opening of the first housing can be connected to one of the third opening and the fourth opening of the second housing by moving one of the first wall and the second wall of the first housing close to one of the third wall and the fourth wall of the second housing so that the first inner space is communicated with the second inner space.
