Study to Determine Efficacy and Safety of Inhaled AeroLEF in the Treatment of Acute Post-op Pain in Adult Patients Undergoing Elective Orthopedic Surgery

Inclusion Criteria: * male and female 18 to 70 years * patient alert and capable of self-administering an opioid anaglesic * Patient is scheduled for orthopedic surgery under general anesthesia * Patient has normal laboratory values * Physical examination with no clincially relevant findings * Patient in general good health based on medical history and clincially acceptable * Patient is able to understand the requirements of the study * Patient is able to communicate effectively with study personnel \_Patient voluntarily gives written approval. Exclusion Criteria: * During Part 2 (randomized period) which involves the use of placebo, patients who are undergoing a major orthopedic procedure that normally requires multimodal analgesia to achieve adequate postoperative pain control (e.g. major spine surgery, total knee arthoplasty) will be excluded. * Patient is taking opioid or non-opioid analgesics on a chronic basis at doses which in the opinion of the investigator would interfere with evaluations of post-operative fentanyl efficacy. * History of pulmonary, cardiovascular, neurologic, endocrine, hepatic, gastrointestinal (GI), or kidney disease or therapy that would jeopardize the patient's well-being by participation in this study. * Patient has documented or self-reported medical history of sleep apnea. * Patient has a documented hypersensitivity to fentanyl or other opioid analgesics. * Patient has a documented hypersensitivity/allergy to the components of the liposomes used in the AeroLEF formulation, including hypersensitivity to soya lecithin or related food products such as soya bean and peanut. * Patient is currently receiving treatment, or has received treatment in the previous two weeks, with monoamine oxidase inhibitors. * Patient has a history of malignancy within the past 5 years, with the exception of successfully treated non?metastatic basal cell or squamous cell carcinomas of the skin and/or localized carcinoma in situ of the cervix. * Patient was dosed with another investigational drug within 30 days prior to the Screening Visit. * Patient has current therapy with CNS-depressant medications (other than stable doses of analgesics and drugs used with surgical anesthesia). * Patient has current evidence of alcohol abuse (regularly drinks more than 4 units of alcohol per day; 1 unit = ½ pint of beer, 1 glass of wine, or 1 ounce of spirit). * Patient has a history of abuse of licit or illicit drug substances. * Patient, who in the opinion of the Investigator, is mentally or emotionally unsuitable to participate, or unable/unwilling to comply with the study assessments.