The development of pulmonary insulin formulation offers an attractive alternative to the current requirement of repeated subcutaneous (s.c.) injections for insulin administration. Technosphere/Insulin is a formulation of regular human insulin that was designed to produce an efficient transport of insulin across the respiratory epithelium into the systemic circulation. Several studies using the euglycemic clamp technique were performed in healthy volunteers and patients with Type 2 diabetes to assess the pharmacokinetic and pharmacodynamic properties of Technosphere/Insulin. The investigations revealed a very rapid systemic insulin uptake (insulin T(max) approximately 12-14 min), a fast onset of action (maximum activity approximately 20-30 min), and a short duration of action (approximately 2-3 h) in healthy volunteers and in patients with Type 2 diabetes. In the first study, employing a commercially available inhaler, the relative bioavailability (compared with s.c. injections) was initially reported to be 26% for the first 3 h and 16% for the entire observation period of 6 h. With the development of a specific inhaler adapted to the physical properties of Technosphere/Insulin, the MedTone Inhaler, relative bioavailability was 50% for the first 3 h and 30% over the entire 6-h period. A clear linearity of systemic insulin uptake was observed in a study employing 12 healthy volunteers inhaling doses of 25, 50, and 100 IU. Repeated inhalation of 100 IU of Technosphere/Insulin by 12 patients with Type 2 diabetes revealed a lower variability in comparison with published s.c. injection data from healthy volunteers. This new Technosphere/Insulin formulation was well tolerated, and no serious adverse events were reported in any of the investigations. Given its attractive time-action profile, Technosphere/Insulin may become a suitable alternative to s.c. injection for prandial insulin delivery, especially in patients with Type 2 diabetes, if the long-term safety, tolerability, and efficacy of this pulmonary insulin are established and confirmed in future studies.