This trial was conducted in North America. The aim of this clinical trial was to investigate if two formulations of NN1250 (insulin degludec) have the same level of drug exposure to the body.

Inclusion Criteria:

• Considered generally healthy upon completion of medical history, physical examination, vital signs and ECG (electrocardiogram), as judged by the Investigator
• Body mass index 18.0-27.0 kg/m^2 (both inclusive)

Exclusion Criteria:

• Subject who has donated any blood or plasma in the past month or more than 500 mL within 3 months prior to screening
• Smoker (defined as a subject who is smoking more than 5 cigarettes or the equivalent per day)
• Not able or willing to refrain from smoking and use of nicotine gum or transdermal nicotine patches during the inpatient period