Effect of relative humidity on drug release from phenytoin sodium tablets and capsules. Part 1: Commercial...

In this study the release rate of the active substance from different lots of commercial tablets and capsules of phenytoin sodium kept in different relative humidities (56, 75, 95%) was studied. It was observed that in both tablets and capsules, the effect of relative humidity and ageing was evident on the in vitro dissolution rate when compared with the in vitro dissolution profiles obtained before storage. The release rate differed from one lot to another after storage, the lots with higher release rates before storage in general showing a decrease and the ones with lower dissolution rates showing a higher release rate after storage.