20 eligible subjects will be enrolled into the treatment phase of the trial.

Trial objectives are to determine the safety & pharmacological response of MKC253 Inhalation Powder.

Inclusion Criteria:

• Non-smoking males and females between 18 and 70 years of age
• Body Mass Index (BMI) of < 32 kg/m2
• Diabetes managed on a stable regimen of diet and exercise within the preceding 8 weeks and/or metformin and/or a sulfonylurea or meglitinide or alpha glucosidase inhibitors, without any dose adjustments within the preceding 8 weeks. For subjects taking both metformin and sulfonylurea or meglitinide or alpha glucosidase inhibitor, one or both oral agents must be less than 1/2 the maximal allowable dose as cited in the product label.
• HbA1c = 6.2 to = 8.5%. Fasting C-peptide = 0.5 ng/mL. On the last 3 days of the washout period (Day -3, -2, and -1) subjects should have a FBG (finger stick) = 13.5 mmol/L.
• Normal pulmonary function and performance on pulmonary function tests
• Written Informed Consent
• Treatment with any type of anti-diabetic therapy other than metformin, sulfonylurea, meglitinide and alpha glucosidase inhibitors within the preceding 12 weeks [ie, thiazolidinediones (TZDs), dipeptyl peptidase inhibitors (DPP-IV), Symlin (pramlintide acetate) and or Byetta (exenatide)].

Exclusion Criteria:

• Exposure to any investigational medications or devices within the previous 90 days prior to trial entry or participation in another clinical trial while participating in this trial.
• Use of any prescription medication within 90 days prior to screening, other than allowed anti-diabetic therapy, that has not been approved by the PI and Sponsor. The use of alpha blockers, antihypertensives, proton pump inhibitors and cholesterol medication as co-medications is allowed throughout the study.
• Significant improvement in pre- to post-bronchodilator spirometry (defined as an increase of 12% AND 200 mL in either FVC OR FEV1).
• Serum creatinine above Upper Limit of Normal (ULN) as defined by the laboratory
• Any other condition which, in the opinion of the PI, makes the subject unsuitable for the clinical trial, or could limit the validity of the informed consent and/or impair the subject's ability to participate in the trial.