Quantitative evaluation of pharmaceutical effervescent systems II: Stability monitoring by reactivity and porosity measurements

The stability of selected effervescent tablet systems was monitored by means of mercury intrusion porosimetry and by a cantilever beam/proximity transducer balance. The porosity measurements proved to be useful in elucidating tablet pore structure changes over time. The measured parameter, percent pores greater than the experimental range, was a useful measure of porosity for statistical evaluations. The study showed that compression pressure and manufacturing conditions are not significant factors in the stability of an effervescent tablet system when nonhygroscopic materials are used.