Publications by authors named "Richard K Burdick"

Comparison of two analytical procedures is the primary objective of a method transfer or when replacing an old procedure with a new one in a single lab. Guidance for comparing two analytical procedures is provided in USP <1010> based on separate tests for accuracy and precision. Determination of criteria is somewhat problematic for these comparisons because of the interdependence of accuracy and precision.

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Product specifications are ideally based on knowledge of patient needs or requirements of subsequent manufacturing steps. However, in most applications, knowledge of patient needs is neither precise nor comprehensive enough to fully define specifications. The prevailing practice is to base specifications on process experience, setting limits to assure consistency of future results with initial results representative of clinical material.

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Tolerance intervals are used to statistically derive the acceptance limits to which drugs must conform upon manufacture (release) and throughout shelf-life. The single measurement per lot in release data and repeated measurements per lot longitudinally for stability data have to be considered in the calculation. Methods for the one-way random effects model by Hoffman and Kringle (HK) for two-sided intervals and Hoffman (H) for one-sided limits are extended to a random-intercept, fixed-slope model in this paper.

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In pharmaceutical analysis, the precision of the reportable value, i.e. the result which is to be compared to the specification limit(s), is relevant for the suitability of the analytical procedure.

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Unlabelled: Analytical similarity is the foundation for demonstration of biosimilarity between a proposed product and a reference product. For this assessment, currently the U.S.

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In this article, the use of statistical equivalence testing for providing evidence of process comparability in an accelerated stability study is advocated over the use of a test of differences. The objective of such a study is to demonstrate comparability by showing that the stability profiles under nonrecommended storage conditions of two processes are equivalent. Because it is difficult at accelerated conditions to find a direct link to product specifications, and hence product safety and efficacy, an equivalence acceptance criterion is proposed that is based on the statistical concept of effect size.

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Individual agreement between two measurement systems is determined using the total deviation index (TDI) or the coverage probability (CP) criteria as proposed by Lin (2000) and Lin et al. (2002). We used a variance component model as proposed by Choudhary (2007).

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The equivalence of two assays is determined using the sensitivity and specificity relative to a gold standard. The equivalence-testing criterion is based on a misclassification rate proposed by Burdick et al. (2005) and the intersection-union test (IUT) method proposed by Berger (1982).

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Bioequivalence studies are conducted to demonstrate equivalence in the bioavailability of the active ingredient in different formulations. The U.S.

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