This is a Phase I, single centre, open label study to assess the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of intravenous AZD3043 after single ascending doses in healthy male volunteers.

Inclusion Criteria:

• Healthy male subjects aged 18 to 45 years with suitable veins for cannulation or repeated venepuncture
• Pre-dose assessment judged without remarks by the investigator
• Have a Body Mass Index (BMI) between 19 and 30 kg/m2 and weight at least 50kg and no more than 100kg

Exclusion Criteria:

• After adequate time (at least 15 minutes) of rest in supine position, abnormal vital signs defined as any of the following:·
• Systolic blood pressure (BP) >140 mm Hg.·
• Diastolic BP >90 mm Hg.
• Heart rate <=55 or >85 beats per minute
• Subjects with compromised airway or respiratory function as evidenced by the presence of Class 3 or 4 Airway, Sleep Apnoea, Neck circumference > 16.5 inches (42 cm), Asthma, Active or recent (2 weeks) respiratory infection, or known chronic respiratory infection, or known chronic respirator
• Lack of a normal phenotype for butyrylcholinesterase (pseudo-cholinesterase)