Bioequivalence of oxycodone hydrochoride extended release tablets to marketed reference products OxyContin® in Canada and US

INTRODUCTION: Oxycodone is a semisynthetic opioid agonist used for the relief of moderate to severe pain. A new generic oxycodone hydrochloride (HCl) extended release (ER) tablet is currently being developed by Ranbaxy Pharmaceutical Inc., New Brunswick, NJ, USA. OBJECTIVE: To assess relative bioavailability of a new generic (test) formulation of oxycodone hydrochloride (HCl) extended release (ER) tablets with that of marketed reference products, OxyContin®, in Canada and USA, in healthy adult subjects under fasting and fed conditions. METHODS: Five studies were conducted in all, three of which were designed to comply with the regulatory criteria for marketing a new generic formulation of OxyContin® in Canada and the remaining two to comply with regulatory criteria for marketing a new generic formulation of OxyContin® in the USA. Each study was a balanced, randomized two-period, two-treatment, two-sequence, crossover design. A single oral dose of test or reference product was given in Period 1, followed by a 7-day washout period, after which subjects received the alternative product in Period 2. In order to block the pharmacological effects of oxycodone, subjects were administered naltrexone HCl (1 × 50 mg tablet) 12 hours prior to oxycodone HCl administration, concurrent with oxycodone HCl administration, and 12 hours after oxycodone HCl administration. Throughout the confinement portion of the study, adverse events were closely monitored. Serial blood samples were collected, following which oxycodone in plasma was estimated using a validated analytical procedure. RESULTS: Oxycodone was well tolerated by subjects in both periods of each study under both fed and fasted conditions. No serious adverse events were observed. The ratios of geometric means for AUC0-t and Cmax and the affiliated 90% confidence intervals for AUC were within acceptance range recommended by Health Canada. These criteria were met for both the raw data as well as data corrected for measured drug content (potency). The ratios of geometric means and the 90% confidence intervals for AUC0-t, AUC0-∞ and Cmax were within acceptance range recommended by United States Food and Drug Administration (FDA). CONCLUSIONS: Results demonstrate that the test formulation of oxycodone HCl ER tablets is bioequivalent to marketed OxyContin® reference formulations in Canada and USA, when administered both under fasted and fed conditions. Additionally, oxycodone HCl ER tablets were well tolerated as a single oral dose when administered to healthy adult subjects under fasted and fed conditions.