The effect of food on the absorption of controlled-release theophylline in mini-swine.

The effect of differing fat contents of food on the bioavailability of theophylline following a 400-mg single dose of Theo-24 was studied in mini-swine. The pharmacokinetics of theophylline, following the intravenous administration of aminophylline equivalent to 5 mg/kg as a single dose, were also studied in the same animals. The terminal plasma half-life of theophylline following an i.v. dose was found to be approximately 24 hr. The volume of distribution, Vdext, and clearance following the i.v. dose were approximately 0.7 liter/kg and 0.023 liter/hr/kg, respectively. The terminal half-life of theophylline following the administration of theophylline capsules under fasting conditions was 21 hr. The average bioavailability under fasting conditions was approximately 80% compared to the i.v. dose. Food appeared to have decreased the rate of absorption but no significant effect on the extent of absorption.