[Pharmaceutical and biologic availability of chlorpromazine from macromolecule-containing tablets]

The use of sufficiently high concentrations of polyvinylpyrrolidone (PVP), hydroxyethyl cellulose (HEC) and methyl cellulose (MC) in tablet formulations leads to depot preparations of the prolonged- or sustained-release type. Having swollen up with the dissolution medium, the tablets form a hydrated matrix from which the active agent diffuses for a considerable time at constant speed. The verification of the bioavailability of chlorpromazine from PVP-, MC- and HEC-containing tablets and of a macromoleculefree standard preparation on rabbits showed considerable differences among the plasma curves. With reference to the standard preparation, the cellulose-containing preparations have a relative bioavailability of 38.8 and 45.7%, respectively. The constancy of the plasma level values for almost 8 h is remarkable. The plasma level profile of these formulations corresponds to that of a depot form of the sustained-release type.