Pharmacokinetics of sustained release and conventional tablets of theophylline plus hydroxyethyltheophylline and its comparison with tablet aminophylline.

Pharmacokinetics of a sustained release (SR) and conventional formulations of theophylline plus hydroxyethyltheophylline was compared with tablet aminophylline. Time concentration curve of serum theophylline with the three formulations after single and multiple dosage schedules revealed significantly retarded absorption with the SR preparation. SR tablet was also seen to produce uniform steady state levels with fluctuation of serum concentrations within the therapeutic range for a duration of over 12 hours. In comparison, aminophylline and conventional theophylline hydroxyethyltheophylline tablets produced sharp swings in steady state levels with trough levels dipping to subtherapeutic concentrations within 4-6 hours. SR formulation, therefore, is likely provide consistent serum levels and better therapeutic control in comparison to the other two conventional tablets.