To evaluate the bioavailability of a tablet of AZD1656.

Inclusion Criteria:

• Male or female, type I diabetes patients, female with non child-bearing potential.
• Treated with insulin for more than 3 years. Well controlled HbA1c.
• Have a body mass index (BMI) ≥19 and ≤35

Exclusion Criteria:

• Clinically significant illness except type I diabetes, or clinically relevant trauma, as judged by the investigator, within 2 weeks before the first administration of the investigational product
• Daily use of nicotine containing substances.