Bioavailability of a once daily-administered theophylline preparation. A comparison study.

To evaluate the bioavailability of a new theophylline preparation suitable for once-a-day (od) oral administration, we performed a nonrandomized crossover study in which the absorption of the OD and a standard twice-a-day (bid) preparation were compared. Eight stable asthmatic patients, after having achieved steady-state, received an average of 975 mg of OD preparation at 8 PM. The protocol was later repeated with the same subjects receiving 487.