Unit Dose Sampling: A Tale of two Thieves

AbstractAs a consequence of the United States vs. Barr Laboratories decision, pharmaceutical companies are now compelled to demonstrate the uniformity of unit dose samples of final powder blends. This investigation was initiated in response to a previously reported failed attempt to validate a process for lower strengths of a currently marketed product. This process has a long history of providing high-quality commercial tablets at the higher strength. The failure occurred because the unit dose samples of the final powder blend were indisputably subpotent. Interestingly, during the validation effort, 799 tablets of various strengths were assayed and exhibited outstanding content uniformity and potency. It was hypothesized that this failure was due to sampling bias which occurred when small (unit dose) samples were extracted with a thief from a static powder bed that was 7 orders of magnitude greater in size. The purpose of this two-part investigation was to test this hypothesis. In both of these studies, ...