Comparative pharmacokinetic analysis of a novel sustained-release dosage form of theophylline in humans.

The pharmacokinetics and relative bioavailability of theophylline from a new sustained-release formulation ( Theotard ) and from a standard sustained-release formulation (Theo-Dur) were compared in 6 healthy, adult, male volunteers. After a single oral dose of 300 mg Theotard , a mean maximal plasma concentration ( Cbmax of 3.49 +/- 1.05 mg/l was obtained after 8 h (tmax). After an identical dose of Theo-Dur, a peak plasma concentration of 4.68 +/- 1.33 mg/l was obtained after 6.33 h. The mean relative bioavailability of theophylline from Theotard was 1.02 +/- 0.16 relative to that of Theo-Dur. In 5 of the volunteers the Theotard formulation exhibited a more prolonged and uniform absorption rate and yielded more sustained plasma levels.