Dose proportionality and the effects of food on bioavailability of an immediate-release oxycodone hydrochloride tablet designed to discourage tampering and its relative bioavailability compared with a marketed oxycodone tablet under fed conditions: a single-dose, randomized, open-label, 5-way crossover study in healthy volunteers.

BACKGROUND: An immediate-release oxycodone hydrochloride formulation (IRO-A) indicated for moderate to severe pain was designed (by adding functional excipients) to discourage tampering associated with intranasal and intravenous abuse of prescription opioids.

OBJECTIVES: The primary objective of this study was to determine the dose proportionality of oxycodone in IRO-A tablets under fasted conditions. Secondary objectives were to assess food effects on the pharmacokinetics of IRO-A tablets, to compare the relative bioavailability of oxycodone in IRO-A tablets versus marketed oxycodone hydrochloride (IRO) tablets under fed conditions and to evaluate the single-dose safety profile of the IRO-A tablets in healthy volunteers pretreated with naltrexone.

METHODS: This open-label, single-dose, randomized, 5-way crossover study was conducted in healthy adults who received each of the following treatments, separated by a washout period of ≥7 days: IRO-A 1 × 5 mg, 2 × 5 mg, and 2 × 7.5 mg under fasted conditions, and IRO-A 2 × 7.5 mg and IRO 1 × 15 mg after a high-fat, high-calorie breakfast. Naltrexone was administered to minimize untoward pharmacologic effects of oxycodone. Dose proportionality (IRO-A), food effects (IRO-A), and relative bioavailability in a fed state (IRO-A and IRO) were assessed by using bioequivalence criteria (90% CIs between 80% and 125% for C(max) and AUC).

RESULTS: Of the 35 adults enrolled in the study, 33 completed at least 1 dosing period. Most participants were male (54%) and white (69%), with a mean (SD) age of 32.6 (11.1) years and mean weight of 75.5 (12.3) kg. Plasma levels of oxycodone in IRO-A suggested dose-proportional pharmacokinetics; 90% CIs for dose-normalized C(max), AUC(0-last), and AUC(0-∞) fell within the 80% to 125% range. Concomitant food intake with IRO-A resulted in an ~14% reduction in oxycodone C(max) and an ~21% increase in AUC(0-last). The bioavailability of oxycodone from IRO-A tablets in the fed state was comparable with IRO tablets based on AUC parameters, although C(max) was ~16.5% lower. Reported or observed treatment-emergent adverse events were monitored throughout the study and were similar for IRO-A and IRO tablets. Nausea, headache, abdominal pain, and dizziness were the most common and are consistent with known effects of oxycodone after naltrexone blockade.

CONCLUSIONS: Plasma levels of oxycodone in IRO-A tablets were compatible with proportional single-dose pharmacokinetics from 5 to 15 mg under fasted conditions. Administration of IRO-A with food suggested increased overall bioavailability relative to fasting conditions and a reduction in peak systemic exposure of oxycodone that is not expected to be clinically significant. When comparing IRO-A tablets with IRO tablets in the fed state, the overall systemic exposure of oxycodone was comparable, and peak systemic exposure was lower.