The invention provides a formulation to be administered as a dry powder for inhalation suitable for efficacious delivery of active ingredients into the low respiratory tract of patients suffering from a pulmonary disease such as asthma. In particular, the invention provides a formulation to be administered as dry powder for inhalation freely flowable, which can be produced in a simple way, is physically and chemically stable and capable of delivering both accurate doses and high fine particle fraction of low strength active ingredients by using a high- or medium resistance device.