To estimate the pharmacokinetics and relative bioavailability of oxycodone after administration of 40 mg doses of PF-00345439 formulations taken whole under fed conditions and after chewing under fasted conditions in healthy volunteers

This study will estimate the pharmacokinetics and relative bioavailability of oxycodone following oral administration of single 40 mg doses of PF-00345439 Formulations J and K compared with the reference PF-00345439 Formulation A, all taken whole and under fed conditions in healthy volunteers.

In addition, the study will estimate the pharmacokinetics and relative bioavailability of oxycodone followingoral administration of single 40 mg doses of PF-00345439 Formulation J or K (to beselected based on Periods 1-3) after chewing under fasted conditions compared to that taken whole in the fed state in healthy volunteers, and assess the single-dose safety and tolerability of oxycodone inPF-00345439 formulations in healthy volunteers when administered under a naltrexone block.

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.
• Positive urine drug test