This is a single-center study incorporating 2 parts: A Multiple Ascending Dose Study (Part A) and a comparative Bioavailability/Bioequivalence and Food Effect study (Part B). Both parts of the study will be conducted in healthy adult subjects.

This study is intended to evaluate the pharmacokinetics of OxyContin (oxycodone ER) and PF614, as well as PF614 fragments, following administration of multiple ascending doses of PF614, and to compare to steady-state pharmacokinetics to those of OxyContin. (Part A)

In addition, oral bioavailability of oxycodone derived from single doses of PF614 of the to-be-marketed capsule formulation will be compared to that of the reference drug, OxyContin, in the fasted and fed condition. A pivotal food effect assessment will be incorporated into the study to determine the impact of a high fat meal on the bioavailability of oxycodone, following oral single-dose administration of PF614 (Part B).

Inclusion Criteria:

• Males or females, ages 18-50 years in good general health,
• BMI between 18 and 32 kg/m (inclusive)
• Subjects must have a negative screen for drugs of abuse, nicotine, alcohol, Hepatitis B, Hepatitis C, and HIV.
• Female subjects of child bearing potential must have a negative serum pregnancy test at randomization
• Females must be of non-child bearing potential (e.g. postmenopausal) or of childbearing potential and agree to use a highly effective form of contraception from the time of screening to two weeks after last dose of study medication.
• Subjects must have normal findings in a physical examination and 12 lead ECG and normal Vital Signs
• Clinical laboratory values must be Within Normal limits as defined by the clinical laboratory
• Subjects must be able to provide coherent written informed consent
• Subjects must be willing and able to follow study instructions and be likely to complete all study requirements.

Exclusion Criteria:

• History of allergy or sensitivity to oxycodone
• History of loud snoring or sleep apnea
• History of medical problems encountered with opioid therapy
• Urinary cotinine levels indicative of smoking or history of smoking or regular tobacco use with 2 months prior to screening
• History of alcoholism or drug abuse
• Use of prescription medications within 14 days of study drug administration with exception of contraceptives used by female subjects
• Use of any opioid within 30 days prior to screening
• History of allergy or sensitivity to naltrexone
• History of allergy or sensitivity to naloxone
• Donation of blood within 30 days prior to screening
• Donation of plasma within 30 days prior to screening
• Acute illness at admission of clinical study unit
• History of GI disturbance requiring use of antacid twice weekly or more
• Females who are breastfeeding
• Anticipated need for surgery or hospitalization during the study
• Enrollment in an investigational drug study within 30 days prior to screening
• Any condition that in the Investigator's opinion puts the subject at significant risk, could confound the study results, or may interfere significantly with the subject's participation in the study.