Polymeric acid compounds have been used for this purpose with some success. This topic and the area of sustained release products has been discussed in more detail in other courses. Benefits for short half-life drugs, sustained release can mean less frequent dosing and thus better compliance. Problems More complicated formulation, may be more erratic in result. A failure of the controlled release mechanism may result in release of a large toxic dose.
Osmotic pressure pushes the drug out at a controlled rate.