A pharmaceutical composition is described. The composition comprises: (i) at least one formoterol compound selected from formoterol, pharmaceutically acceptable salts of formoterol, prodrugs of formoterol, solvates of formoterol, solvates of pharmaceutically acceptable salts of formoterol and solvates of prodrugs of formoterol; (ii) at least one corticosteroid; (iii) a surfactant component comprising at least one surfactant compound; and (iv) a propellant component comprising 1,1 - difluoroethane (R-152a).