Cynthia Y. Robinson, PhD
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Christopher M. Rubino, PharmD
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Stephen J. Farr, PhD
Objectives: To assess the single-dose and steady-state pharmacokinetics of a single-entity hydrocodone extended-release (ER) formulation in patients enrolled in two separate phase 2 clinical studies.Setting: Both studies were multicenter clinical studies.Subjects and interventions: In study 1, 115 subjects with postsurgical pain (bunionectomy) received single doses of 10, 20, 30, or 40 mg hydrocodone-ER, 10 mg hydrocodone/325 mg acetaminophen immediate-release (IR), or placebo. In study 2, 37 subjects with osteoarthritic pain received doses of 10, 20, 30, or 40 mg of hydrocodone-ER twice-daily for 7 days. Venous blood samples were taken periodically up to 24 hours postdosing after the single dose (study 1) or after 7 days of dosing (study 2) and were assayed for concentrations of hydrocodone and its major metabolites.Main outcome measures: Standard pharmacokinetic parameters were estimated by noncompartmental analysis methods.Results: Following a single dose of hydrocodone-ER, Tmax was prolonged to approximately 6 hours at all dose levels of hydrocodone-ER compared with 2.9 hours for the IR formulation. All doses of hydrocodone-ER formulations provided prolonged and sustained release of hydrocodone throughout the 12-hour dosing interval with reduced peak-to-trough fluctuation at steady state compared with hydrocodone/acetaminophen-IR comparator. Both single-dose and steady-state mean Cmax and AUClast values showed reasonable dose-proportionality. Norhydrocodone and hydromorphone plasma concentrations were 32-38 percent and <2.1 percent, respectively, of hydrocodone concentrations in both studies.Conclusions: The sustained plasma concentrations of hydrocodone support twice-daily dosing with a 12-hour dosing interval.
Steady-state pharmacokinetics and bioavailability of immediate-release and extended-release formulations of lamotrigine in elderly epilepsy patients: Use of stable isotope methodology
