title: Comparative bioavailability of sustained-release and conventional tablets of hydroxyethyltheophylline in man.
abstract: The comparative bioavailability of sustained-release and conventional tablets of hydroxyethyltheophylline was studied in normal subjects. In a single dose study on 7 subjects, 3 conventional tablets or 2 sustained-release tablets were administered orally after a light breakfast and blood samples taken for 6 and 12 hours respectively. With conventional tablets the mean peak concentration (8.10 +/- 0.751 microgram/ml) was reached at 3 hours and concentrations less than 5 microgram/ml were observed in 4 out of 7 subjects at 6 hours. In contrast, with sustained-release tablets of theophylline and hydroxytheophylline complex the mean peak concentration (8.90 +/- 0.88 microgram/ml) was reached at 6 hours and levels above 5 microgram/ml were observed in 4 out of 7 cases at 12 hours. Administration of 2 sustained-release tablets twice a day produced trough plasma concentrations varying between 6.9-13.8 microgram/ml, i.e. within the therapeutic range in all the 5 subjects. It is concluded that this new oral sustained-release preparation provides therapeutic plasma theophylline concentration on a 12 hourly dosage schedule.
mesh_terms: D001682:Biological Availability; D003692:Delayed-Action Preparations; D005260:Female; D006801:Humans; D008297:Male; D013607:Tablets; D013806:Theophylline / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D013997:Time Factors
chemical_list: D003692:Delayed-Action Preparations; D013607:Tablets; D013806:Theophylline