Dissolution behavior of commercial Theodur 50.

Dissolution behavior of a newly designed, commercially available sustained-release tablet of theophylline containing 50mg (Theodur® 50) was measured according to the J. P. X dissolution test procedures in pH 1.2, 6.8, and pH1.2 adding 0.25% Tween 80 solutions.The following results were obtained: The release from Theodur® 50 was pH-independent, but was much affected by wet and rotating velocity of dissolution test.The required time for 50% dissolution at 100rpm was about 2 times as large as at 200rpm.