Evaluation of RETESTING In Pharmaceutical (Quality Control) Industry.

Evaluation of RETESTING In Pharmaceutical (Quality Control) Industry.

Evaluate the company’s retesting SOP for compliance with scientifically sound and appropriate procedures. A very important ruling in one recent court decision sets forth a procedure to govern the retesting program. This district court ruling provides an excellent guide to use in evaluating some aspects of a pharmaceutical laboratory, but should not be considered as law, regulation or binding legal precedent. The court ruled that a firm should have a predetermined testing procedure and it should consider a point at which testing ends and the product is evaluated. If results are not satisfactory, the product is rejected.

Additionally, the company should consider all retest results in the context of the overall record of the product. This includes the history of the product. The court ordered a recall of one batch of product on the basis of an initial content uniformity failure and no basis to invalidate the test result and on a history of content uniformity problems with the product., type of test performed, and in-process test results. Failing assay results cannot be disregarded simply on the basis of acceptable content uniformity results.

The number of retests performed before a firm concludes that an unexplained OOS result is invalid or that a product is unacceptable is a matter of scientific judgment. The goal of retesting is to isolate OOS results but retesting cannot continue ad infinitum.

In the case of nonprocess and process-related errors, retesting is suspect. Because the initial tests are genuine, in these circumstances, additional testing alone cannot contribute to product quality. The court acknowledged that some retesting may precede a finding of nonprocess or process-based errors. Once this determination is made, however, additional retesting for purposes of testing a product into compliance is not acceptable.

For example, in the case of content uniformity testing designed to detect variability in the blend or tablets, failing and non-failing results are not inherently inconsistent and passing results on limited retesting do not rule out the possibility that the batch is not uniform. As part of the investigation firms should consider the record of previous batches, since similar or related failures on different batches would be a cause of concern.

Retesting following an OOS result is ruled appropriate only after the failure investigation is underway and the failure investigation determines in part whether retesting is appropriate. It is appropriate when analyst error is documented or the review of analyst’s work is “inconclusive” , but it is not appropriate for known and undisputed non-process or process related errors.

The court ruled that retesting:

– must be done on the same, not a different sample

– may be done on a second aliquot from the same portion of the sample that was the source of the first aliquot

– may be done on a portion of the same larger sample previously collected for laboratory purposes




Pharmaceutical Quality Control Labs (7/93)


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