This is an open-label (both the physician and healthy volunteer know which medication will be administered), single-dose, 6- dosing period study to characterize the pharmacokinetics of oxycodone (process by which oxycodone is absorbed, distributed, metabolized, and eliminated by the body). This study will consist of three parts that will take place over approximately 90 days. Part 1 of the study has 4 dosing periods, while Parts 2 and 3 have one dosing period each.

This study will estimate the PK and relative BA of oxycodone following single oral 40-mg doses of 3 modified PF-00345439 Formulations E, F, and G compared with the reference PF-00345439 Formulation A under fed conditions in healthy volunteers in order to aid in selection of a final formulation.

Inclusion Criteria:

• Healthy male and/or female subjects between 18 and 55 years of age (inclusive).

Exclusion Criteria:

• Evidence or history of clinically significant disease.
• History of obstructive sleep apnea.
• Positive urine drug test.