The dissolution rates of theophylline from four products (three sustained-release formulations and a conventional tablet) were determined by the rotating basket method and, the paddle method in JP 10 dissolution apparatus. From the data obtained under the condition of the rotating basket method at a stirring rate of 200rpm, there was no significant difference between two sustainedrelease formulations, Theo-dur^® tablet and E-0686 granule, as shown in the previous bioavailability studies. This condition was employed for the dissolution tests for sustained-release product of theophylline.
Dissolution studies of halved pd crushed sustained-released tablets, which are commonly dosed to children, revealed that the drug release rates from these tablets were significantly higher than those from the whole tablets.