Effects of time of dose in relation to food on the bioavailability of Theo-Dur Sprinkle at steady state in asthmatic children

The effects of administration of Theo-Dur Sprinkle in the fasting state (phase A), 10 minutes before food (phase B), and immediately after food (phase C) were investigated in 12 children with asthma aged 5 to 9 years at steady state. The AUC during the dosing interval was significantly reduced in phases B and C compared with phase A, and bioavailability relative to the fasting state was reduced to 77% ± 15% (range 61% to 104%) in phase B and 70% ± 16% (range 40% to 103%) in phase C. The average plasma theophylline concentration during the dosing interval and C_max were also significantly reduced in phases B and C compared with phase A. The morning predose plasma theophylline concentration in phase B was 22% lower than the predose concentration with Theo-Dur tablets taken 10 minutes before breakfast. The diurnal variation in predose plasma theophylline concentrations was increased from 28% in phase A to 63% in phase C. There was no significant difference in any parameter between administration 10 minutes before food and immediately after food.