title: A cross-over study of oral and intravenous administration of theophylline in male volunteers. Absolute bioavailability of theophylline tablets.
abstract: Seven normal male volunteers each received an injection of 208 mg theophylline anhydride for 4 min, and a 185-mg single oral dose theophylline anhydride (Broncho-Afonilum) on separate occasions. The concentrations of unchanged theophylline was analyzed over a 24-h period in plasma and a 48-h period in urine after both dosage forms. A 2-compartment model was required to describe the intravenous plasma concentration-time course in all seven subjects. A 1-compartment model sufficed to account for the decay of the oral plasma concentrations in all subjects. The mean plasma t1/2 after i.v. dosing was 6.5 h (3.5-9 h), and the mean plasma t1/2 after oral doses was 5.7 h (3-12 h). The calculated total of 23% (11-70%) of the intravenous dose was excreted in urine, and the mean total excretion after the oral dose was 12% (7-19%). The absolute bioavailability of oral theophylline was 94 +/- 20%
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D013607:Tablets; D013806:Theophylline / Q000008:administration & dosage* / Q000378:metabolism
chemical_list: D013607:Tablets; D013806:Theophylline