A Safety and Efficacy Study of Different Injections Volumes of Botulinum Toxin Type A, Azzalure, in the Glabellar Lines

Key Inclusion Criteria: * Women, 18 to 64 years of age * Subjects seeking treatment for moderate to severe glabellar lines when the severity of these lines has an important psychological impact on the subject, as determined by the investigator. Key Exclusion Criteria: * Subjects previously treated with any botulinum toxin product. * Pregnant or breast feeding women or women intending to get pregnant in the next 12 months. * Subjects with signs and symptoms of eyelid or brow ptosis or signs of compensatory frontalis muscle activity, as judged by the investigator. * Subjects with clinical or subclinical neuromuscular junctional disorders (e.g. myasthenia gravis, Lambert Eaton syndrome or amyotrophic lateral sclerosis) or a history of dysphagia or aspiration. * Subjects with previous or current diagnosis of Bell's paresis. * Subjects with known bleeding disorders or subjects who are taking thrombolytics or anticoagulants. * Subjects who are taking anticholinergics or aminoglycoside antibiotics. * Any prior surgery in the facial area that, in the opinion of the investigator, may interfere with the results. * Subjects treated with fillers, HA filler or permanent filler, in the upper face one year or less from screening.