To evaluate the bioavailability of a single oral dose of the Acetylsalicylic Acid containing dry powder 500 mg in comparison to the bioavailability of a single oral dose of aspirin tablets and aspirin effervescent tablets in healthy adults.

Inclusion Criteria:

• Healthy ,male and female subjects 18 to 55 years of age, inclusive
• Body Mass Index (BMI) of approximately 18 to 30 kg/m2, and a total body weight >50 kg (110 lbs)
• Results of screening and clinical laboratory tests are within normal limits or considered not clinically significant by the Principal Investigator or Sponsor
• Female subjects of childbearing potential must be using a medically acceptable form of birth control for at least 1 month prior to screening (3 months on oral contraceptives), e.g., oral or patch contraceptives, intrauterine device, intramuscular injection or double-barrier and have a negative pregnancy test at Screening and on Day 0 of each treatment period. Female subjects of nonchildbearing potential must be amenorrheic for at least 2 years or had a hysterectomy and/or bilateral oophorectomy.

Exclusion Criteria:

• History of hypersensitivity to acetylsalicylic acid (ASA), naproxen sodium, acetaminophen, other non-steroidal anti-inflammatory drugs (NSAIDs), and similar pharmacological agents or components of the products
• History of gastrointestinal bleeding or perforation, including bleeding related to previous NSAID therapy. Active, or history of recurrent peptic ulcer/hemorrhage (two or more distinct episodes of proven ulceration or bleeding).
• Have taken ASA, ASA-containing products, acetaminophen or any other NSAID (OTC or prescription) seven days prior to dosing or during the Treatment Periods, other than study product
• Loss of blood in excess of 500 mL within 56 days of the first dose of trial treatment (e.g., donation, plasmapheresis, or injury)
• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic disease, or malignancies
• Positive alcohol or drug screen at Screening or on Day 0 of Treatment Periods 1,2 and 3
• Females who are pregnant or lactating