Kerry John Hartauer

Influence of peroxide impurities in povidone and crospovidone on the stability of Raloxifene hydrochloride in tablets : Identification and control of an oxidative degradation product

The purpose of this study was to identify a degradation product in a tablet formulation of raloxifene hydrochloride (R-HCl), delineate the role of excipients in its formation, and develop a rational strategy for its control. The degradant was identified as an N-oxide derivative of the drug substance based upon spectroscopic characterization and chromatographic comparison to the synthetic N-oxide. To identify the factors contributing to the formation of N-oxide, binary mixtures of each excipient with R-HCl were exposed to 125°C in open containers. Raloxifene hydrochloride underwent an order of magnitude increase in conversion to the N-oxide in the presence of two excipients, povidone and crospovidone, as compared with its conversion in the presence of other excipients. To confirm a hypothesis that peroxide impurities in these two excipients contributed to the oxidation of the drug substance, tablet lots were spiked with quantities of H2O2 equivalent to 200, 400, 600, and 800 ppm peroxide over the intrinsic levels present in povidone and crospovidone. A strong correlation was observed between the total peroxide level and the quantity of the N-oxide formed upon accelerated storage. From these experiments a rational limit test for peroxide content in povidone and crospovidone was adopted as part of a control strategy to limit formation of the degradation product.

Summary Workshop Report: Bioequivalence, Biopharmaceutics Classification System, and Beyond

The workshop “Bioequivalence, Biopharmaceutics Classification System, and Beyond” was held May 21–23, 2007 in North Bethesda, MD, USA. This workshop provided an opportunity for pharmaceutical scientists to discuss the FDA guidance on the Biopharmaceutics Classification System (BCS), bioequivalence of oral products, and related FDA initiatives such as the FDA Critical Path Initiative. The objective of this Summary Workshop Report is to document the main points from this workshop. Key highlights of the workshop were (a) the described granting of over a dozen BCS-based biowaivers by the FDA for Class I drugs whose formulations exhibit rapid dissolution, (b) continued scientific support for biowaivers for Class III compounds whose formulations exhibit very rapid dissolution, (c) scientific support for a number of permeability methodologies to assess BCS permeability class, (d) utilization of BCS in pharmaceutical research and development, and (e) scientific progress in in vitro dissolution methods to predict dosage form performance.

Summary Workshop Report: Facilitating Oral Product Development and Reducing Regulatory Burden Through Novel Approaches to Assess Bioavailability/ Bioequivalence

This summary workshop report highlights presentations and over-arching themes from an October 2011 workshop. Discussions focused on best practices in the application of biopharmaceutics in oral drug product development and evolving bioequivalence approaches. Best practices leverage biopharmaceutic data and other drug, formulation, and patient/disease data to identify drug development challenges in yielding a successfully performing product. Quality by design and product developability paradigms were discussed. Development tools include early development strategies to identify critical absorption factors and oral absorption modeling. An ongoing theme was the desire to comprehensively and systematically assess risk of product failure via the quality target product profile and root cause and risk analysis. However, a parallel need is reduced timelines and fewer resources. Several presentations discussed applying Biopharmaceutics Classification System (BCS) and in vitro–in vivo correlations in development and in post-development and discussed both resource savings and best scientific practices. The workshop also focused on evolving bioequivalence approaches, with emphasis on highly variable products (HVDP), as well as specialized modified-release products. In USA, two bioequivalence approaches for HVDP are the reference-scaled average bioequivalence approach and the two-stage group-sequential design. An adaptive sequential design approach is also acceptable in Canada. In European Union, two approaches for HVDP are a two-stage design and an approach to widen Cmax acceptance limits. For some specialized modified-release products, FDA now requests partial area under the curve. Rationale and limitations of such metrics were discussed (e.g., zolpidem and methylphenidate). A common theme was the benefit of the scientific and regulatory community developing, validating, and harmonizing newer bioequivalence methodologies (e.g., BCS-based waivers and HVDP trial designs).