 Part B: A total of 44 patients will be enrolled. Subjects will be randomized to a 4-period cross-over study aiming at comparing the performance of BC Lispro and Humalog after a prandial bolus administration with two different CSII systems Roche Accu-Chek Spirit and Medtronic Paradigm VeoTM or with a syringe. Pharmacodynamics, pharmacokinetics, pump compatibility and safety will be analyzed. 