Correlation between in vivo mean dissolution time and in vitro mean dissolution time of ampicillin products.

The mean in vitro dissolution times (in vitro MDT) of ampicillin products were evaluated from the dissolution curves in distilled water using the USP-XX dissolution apparatus, and were compared with the mean in vivo dissolution times (in vivo MDT) reported previously. In both in vivo and in vitro cases, MDT of the trihydrate capsule was greater than those of the anhydrate capsules. A good linear correlation was observed between in vivo and in vitro MDT (r = 0.999, p less than 0.001).