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.