Single dose study of the bioequivalence of two sustained-release theophylline formulations.

The relative bioavailability of theophylline (CAS 58-55-9) was evaluated after a single dose administration of two sustained-release theophylline tablet formulations: Controfilina-200 as test preparation (test) and a commonly used reference preparation (reference). The design of the study was crossover in twelve healthy volunteers, with a series of two experimental sessions. The two sessions were carried out at weekly intervals. Theophylline concentrations were measured by HPLC (high performance liquid chromatography). The bioavailability was compared using the parameters: AUC0-infinity (area under the concentration-time curve), Cmax (maximal theophylline concentration), tmax (time after drug intake at which the maximal concentration is reached) and Cmax/AUC0-infinity. The results of this study indicated that the new generic sustained-release tablet and the reference are bioequivalent when the same dosage is administered.