Theophylline bioavailability following oral administration of six sustained-release preparations.

Plasma theophylline concentrations were measured in 20 adults after single doses of 8 mg/kg of each of six oral sustained-release theophylline preparations. Twelve subjects were studied in a multiple-dose trial. Comparison of bioavailability and absorption characteristics suggest usefulness of some of these products for the purpose of maintaining safe and effective blood levels with twice-a-day dosing.