Pharmacokinetic study of controlled-release choline theophyllinate in elderly patients

Controlled-released choline theophyllinate tablets (Sabidal SR 270, Zyma) were administered to 17 elderly patients aged between 68 and 86 years (mean 76 +/- 7 years) until steady state was obtained. The dosage form was one tablet every 12 hours for four days. Plasma theophylline concentrations were measured by high-performance liquid chromatography after the first dose and during the fourth day for a 12-hour period. The tablets showed evidence of controlled-release properties: the maximum plasma concentration (10.8 +/- 2.5 mg/l) was obtained after 3.4 +/- 1.6 hours. The mean trough level was 6.6 +/- 1.5 mg/l and the difference between the peak and trough levels was 4.1 +/- 1.2 mg/l. The mean steady-state plasma theophylline concentration was 8.5 +/- 2.2 mg/l. The mean elimination half-life was 14 +/- 7 hours. The mean volume of distribution was 0.8 +/- 0.4 l/kg. The mean total body clearance was 0.05 +/- 1/h/kg. All values, the half-life excepted, were found to be within the ranges for the patients reported in the literature. The values show the usual interindividual variation.