Pharmacokinetics/Dynamics of Basal (Continuous) Insulin Infusion Administered Either Intradermally or Subcutaneously

20 Male Type 1 Diabetic Mellitus subjects on Continuous Subcutaneous Insulin Infusion (CSII) therapy. Inclusion Criteria: * Understood and signed informed consent obtained before any trial-related activities (trial-related activities are any procedures that would not have been performed during normal management of the subject) * Type 1 Diabetes mellitus, according to clinical judgment / ADA / WHO-definition (Diabetes Care 2003; 26: 5-20) for at least 1 year * Current treatment:Insulin Pump * Age in the range of greater than or equal to 18 and less than or equal to 55 years * Body mass index (BMI) less than or equal to 32 kg/m² * HbA1c less than or equal to 9.0 % * Able and willing to adhere to the study procedures for the entire trial period * Negative test results for hepatitis C antibodies, hepatitis B surface antigen and HIV at screening. Exclusion Criteria: * Previous participation in this trial or participation in a clinical trial within 3 months prior screening examination * Any symptoms suggestive of, or a diagnosis or treatment for gastroparesis * Abnormalities in renal function (e.g. serum creatinine \>1.2 mg/dl) or judged by the investigator that would pose a problem of clearance of injected insulin * Proliferative retinopathy or maculopathy that has required acute treatment within the last six months * Acute and severe illness apart from diabetes mellitus as judged by the investigator * Abnormalities in the laboratory parameters if judged as clinically significant by the investigator. In particular, subjects with GOT/GPT \>3x, thrombocyte count \<100/nL, INR \>1.3, PTT \>50 sec. will not be permitted to enter the study. * Clinically significant abnormalities in the ECG * Recurrent major hypoglycemia or hypoglycemic unawareness as judged by the investigator * Lipodystrophy which in the judgment of the investigator would pose a problem in terms of variability of absorption of injected insulin * Use of systemic corticoids for the last three months prior to screening examination or treatment with medication known to interfere with glucose metabolism such as non-selective ß-blockers, or mono amine oxidase (MAO) inhibitors, ACE-inhibitors or thiazides, unless medical treatment having existed for at least three month prior screening examination * Any disease requiring use of anti-coagulants * Impaired hepatic or renal functions as judged by the investigator * Cardiac problems as judged by the investigator * Uncontrolled hypertension (treated or untreated) as judged by the investigator (RRsyst. \>140 mmHg, RRdiast. \> 90 mmHg) * Mental incapacity, unwillingness or language barriers precluding adequate understanding or co-operation * Current addiction to alcohol or substances of abuse as determined by the investigator * Allergy to plaster/adhesive * Any other condition that the investigator feels would interfere with trial participation or evaluation of results. * Donation of any blood or plasma in the past month or in excess of 500 mL within the 12 weeks preceding screening * Subjects with a history of deep leg vein thrombosis or with frequent appearance of deep leg vein thrombosis in 1st degree relatives as judged by the investigator