PHARMACOKINETIC EVALUATION OF SUSTAINED-RELEASE FORMULATIONS OF THEOPHYLLINE BY ANALOG HYBRID SIMULATION

Several new formulations of theophylline, loaded on polystyrene beads, were developed. Their sustained release performance was evaluated by in vitro dissolution test. Analog-hybrid simulation was carried out in order to evaluate the influence of some technological parameters on the pharmacokinetics of theophylline. Single- and multiple-phase processes of dissolution were proposed. Furthermore, predicted plasma levels in single- and multiple-dosage-regimen schemes were obtained. Formulations with a first-order release rate constant lower than 1.0 h-1 can be administered as a sustained release dosage form at 12-h intervals. © 1990.