title: Application of stable isotope methodology in the evaluation of sustained-release theophylline dosage forms.
abstract: We compared the kinetics of a single daily dosage form of theophylline (Theo-24) with the kinetics of a twice daily dosage form (Theo-Dur) while we controlled for intrasubject variation in theophylline clearance by use of stable isotope-labeled intravenous theophylline. The stable isotope methodology allowed correction for changes in patient clearance, which allowed more precise estimates of the bioavailability characteristics of these sustained-release theophylline products.
mesh_terms: D001682:Biological Availability; D003692:Delayed-Action Preparations; D006801:Humans; D007554:Isotopes; D013806:Theophylline / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D003692:Delayed-Action Preparations; D007554:Isotopes; D013806:Theophylline