Effect of food on the bioavailability and pattern of release of a sustained-release theophylline tablet

The effect of food on the bioavailability, time to peak level, and pattern of release of a sustained-release theophylline preparation was examined in six normal volunteers. The average bioavailability for the 100- and 300-mg tablets was 98 +/- 0.03% (S.E.M.). This is consistent with previously published data. Food decreased measured theophylline concentration during the first 4 hours for the 100-mg tablets and at the fourth-hour sample following the 300-mg tablets. The decreased rate of absorption resulted in a shift of the absorption curve to the right with a delay in the time to peak level. Peak serum concentrations for tablets given with a meal occurred 6 hours after the 100-mg tablets and 8 hours after the 300-mg tablets, as opposed to 4 and 6 hours, respectively, for tablets in the fasting state. The release pattern of the theophylline preparation approximated zero-order kinetics for all fasting and food treatments.