The purpose of this research study is to evaluate the effect of AZD1981 on the electrical activity of the heart, in particular when the heart muscle is relaxed during a heart beat cycle. The effect of AZD1981 will be compared to a licensed antibiotic (moxifloxacin) which is well known to affect the electrical activity of the heart, but this effect is known to be at levels that are safe at the dose used in this study. The investigators will also compare the effects of AZD1981 with a "dummy drug" (placebo). The investigators will also be evaluating how safe and well tolerated AZD1981 is and how much AZD1981 enters the blood circulation by collecting blood during the study.

Inclusion Criteria:

• Healthy male volunteers aged 18 to 55 years (inclusive)
• Subjects must be willing to use barrier methods of contraception during study and for 3 months after last dosing.
• Be a non-smoker or ex-smoker who has stopped smoking for >6 months

Exclusion Criteria:

• Any clinically significant disease or disorder (eg, cardiovascular, pulmonary, gastrointestinal, liver, renal, neurological, musculoskeletal, endocrine, metabolic, malignant, psychiatric, major physical impairment)
• History of additional risk factors for Torsade de Pointes (eg, heart failure, hypokalemia, personal or family history of arrhythmia or long QT syndrome)