Pharmacokinetics of whole and half Theo-Dur tablets

The bioavailability and absorption patterns of whole and divided sustained-release theophylline tablets, Theo-Dur, were investigated. Both whole and divided tablets were well absorbed. The rates of absorption differed. The mean absorption time for whole tablets was 5.7 h and for divided tablets 4.2 h. The influence of these differing mean absorption times on the appearance of the serum curves is negligible, and the sustained action is maintained also after breaking the tablets. The present investigation shows that Theo-Dur tablets can be broken for dosage convenience, still maintaining the sustained action.