Batch placebo method
9.4 Batch placebo method
Note: This method relies on the manufacture of a placebo batch which is then checked for carry-over of the previous product. It is an expensive and laborious process. It is difficult to provide assurance that the contaminants will be dislodged from the equipment surface uniformly. Additionally, if the particles of the contaminant or residue are large enough, they may not be uniformly dispersed in the placebo batch.
9.4.1 The batch placebo method should be used in conjunction with rinse and/or surface sampling method(s).
9.4.2 Samples should be taken throughout the process of manufacture.
Traces of the preceding products should be sought in these samples. (Note that the sensitivity of the assay may be greatly reduced by dilution of the contaminant.)