The purpose of this study is to determine the effect of pain relief with AeroLEF in adult patients, following 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.