[A comparative study of the pharmacokinetics and urinary metabolites of sustained-release theophylline syrup, granule and tablet preparations].
Three different theophylline preparations, theophylline syrup, granule and tablets, were examined to determine their pharmacokinetics and changes in urinary metabolites for each steady state phase. The theophylline syrup was as rapidly and as essentially bioavailable as the theophylline granule preparation. In addition, peak to trough differences in serum theophylline concentrations were largest for theophylline syrup and lowest for tablets. Tmax was greater in theophylline tablets and a significant difference was apparent in the tablet-syrup and tablet-granule populations. AUC and T1/2 were similar in these populations. Cmax and Cmin achieved satisfactory therapeutic theophylline levels in three different preparations, and t-test showed no significant difference between them. CL and Vd were also similar. The urinary metabolites of theophylline were expressed as internal standard equivalents on a molar basis. There were no significant changes between either tested preparations different or different age groups. Therefore, we concluded that theophylline syrup and granules should be administered on a 3-times-daily basis, considering trough plasma theophylline levels. Theophylline tablets are preferable, if they can be taken.
Horiuchi
Y
Y
Division of Pediatrics, National Sengokusoh Hospital.
Takemura
T
T
Ueno
K
K
D000293:Adolescent; D001249:Asthma / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003692:Delayed-Action Preparations; D004304:Dosage Forms; D005260:Female; D006801:Humans; D008297:Male; D013806:Theophylline / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000652:urine
D003692:Delayed-Action Preparations; D004304:Dosage Forms; D013806:Theophylline