A Study to Evaluate the Efficacy and Safety of Meptin® Swinghaler and Berotec N® Metered Aerosol in Mild to Moderate Stable Asthma Patients

Inclusion Criteria: * Male or females outpatients aged ≥18 years old with uncontrolled or partly controlled asthma; Stability was assessed during the past 14 days the patients remained in the same severity class by 2006 GINA guideline (uncontrolled, partly controlled) and had no acute exacerbations by investigator judgment; * Pulmonary function test: Improvement ≥12% reversibility in FEV1 or FVC following administration of an inhaled β2-agonist before the study or ; Positive result of Brocho-provocation test; Exclusion Criteria: * Hypersensitivity to β2-agonist or lactose; * Hospitalization due to asthma during the previous 3 months; * Respiratory tract infection requiring treatment with antibiotics in the previous 4 weeks; * Oral or systemic corticosteroids in the previous 4 weeks; * Inadequately controlled hyperthyroidism; * Subjects with any clinically significant disorder of the cardiovascular, neurologic, hematologic, gastrointestinal, cerebrovascular, or immunologic system or respiratory disease other than asthma(e.g. COPD), or any other disorder which may interfere wth the study evaluations or affect subject safety; * Patients receive an investigational drug within 30 days prior to admission to the study; * Patients with significant alcohol, drug or medication abuse as judged by the investigator; * Females who are pregnant or breast-feeding; (exception: Females of child-bearing age might be included, if in the opinion of the investigator, they are using adequate contraceptive precautions); * Subjects who are heavy smoker (more than 10 packs year) or who are smoking within previous 6 months.