In a recent publication from USP it is concluded that,
“Apparatus 1 results are stable over time. Those in Apparatus 2 show a decrease over time in the geometric mean but show no trend in variability”.
If all things being equal for testing except differences in apparatuses used, then is it not obvious that instability in results would reflect the instability of Apparatus 2? The conclusion from the USP supports the observation/results reported in the literature regarding poor performance of Apparatus 2. This poor performance in testing is a reflection of poor hydrodynamic environment within dissolution vessels as described extensively in literature. Thus, the use of Apparatus 2 would require caution.
