All six tablets for a dissolution test were dropped in about one minute, but were withdrawn over a period of two minutes. The last two samples were taken beyond the time limit specified for the dissolution test. Sustained released dissolution samples which required change from SGF for the 1st hour time point to SIF for the 2nd hour time point were observed to take six minutes for the changeover and ten minutes to restart. The first vessels were in SIF for more than one hour and the last vessels were in SGF for more than one hour. Start and stop times for dissolution tests are not documented to ensure that aliquots are taken within specified time limits.
Media change at the one-hour time point involved changing the dissolution vessels.
The numbers marked on the vessels indicated that the vessels were not replaced in the same order. After the first time point sample was removed, the paddle blades were wiped, resulting in the removal of some material from the paddles. After withdrawal of the sample for the first time point, the excess sample in the syringe was discharged back into the vessel causing agitation of the remaining tablet fragments. The filters used for filtering dissolution samples have not been checked for adsorptive loss of drug. The potential for cross-contamination of samples was incurred since the same filter was used to filter all samples within a dissolution run.