Pharmacokinetics of a novel liquid controlled release codeine formulation

Codeine is an important opioid anti-tussive agent whose short half-life (2.9 ± 0.7 h) requires that it be administered at 4-h intervals when formulated as a simple aqueous solution. Liquid controlled release codeine formulations such as an older Codipertussin® formulation, which contained codeine bound to an ion exchange resin and coated with a retardant polymer, achieved an equivalent bioavailability when administered every 12 h. An accompanying paper described the development and in vitro characterization of a novel Codipertussin® formulation containing a non-coated codeine:ion exchange resin (Amberlite IR 69 F) complex. In this study, the bioavailability of codeine from this new liquid controlled release formulation was investigated in an open label, single center, randomized, steady-state, cross-over study in healthy male volunteers. Participants received either 69.7 mg codeine as the controlled release liquid form every 12 h or 23.2 mg codeine in solution every 4 h. Controlled release from the suspen...