Using Manufacturing Design Space Concepts for Stability Risk Assessment-Gabapentin NIPTE/FDA Case Study

Benefits of Fractal Approaches in Solid Dosage Form Development

Pharmaceutical formulations are complex systems consisting of active pharmaceutical ingredient(s) and a number of excipients selected to provide the intended performance of the product. The understanding of materials' properties and technological processes is a requirement for building quality into pharmaceutical products. Such understanding is gained mostly from empirical correlations of material and process factors with quality attributes of the final product. However, it seems also important to gain knowledge based on mechanistic considerations. Promising is here to study morphological and/or topological characteristics of particles and their aggregates. These geometric aspects must be taken into account to better understand how product attributes emerge from raw materials, which includes, for example, mechanical tablet properties, disintegration or dissolution behavior. Regulatory agencies worldwide are promoting the use of physical models in pharmaceutics to design quality into a final product. This review deals with pharmaceutical applications of theoretical models, focusing on percolation theory, fractal, and multifractal geometry. The use of these so-called fractal approaches improves the understanding of different aspects in the development of solid dosage forms, for example by identifying critical drug and excipient concentrations, as well as to study effects of heterogeneity on dosage form performance. The aim is to link micro- and macrostructure to the emerging quality attributes of the pharmaceutical solid dosage forms as a strategy to enhance mechanistic understanding and to advance pharmaceutical development and manufacturing processes.

Pharmaceutical "New Prior Knowledge": Twenty-First Century Assurance of Therapeutic Equivalence

Facilitating utility of prior knowledge to accelerate evidence-based new drug development is a focus of several communities of knowledge, such as clinical pharmacology. For example, progress has been made via modeling and simulation of pharmacokinetic and pharmacodynamic relationships in the more effective use of “End of Phase 2” regulatory meetings for a New Drug Application (NDA). Facilitating utility of prior “Chemistry, Manufacturing, and Controls” (CMC) knowledge to accelerate new drug development and regulatory review process is also a topic of significant interest. This paper focuses on facilitating the utility of prior pharmaceutical formulation knowledge to accelerate drug product development and regulatory review of generic and biosimilar products. This knowledge is described as New Prior Knowledge (NPK) because research is often needed to fill ontological (i.e., the domain of connectivity between concepts and phenomena), epistemological (i.e., distinguishing knowledge or justified belief from the opinion), and methodological gaps in information derived a decade or so ago. The corporate economic advantages of such knowledge are derived, in part, when significant portions remain a trade secret. The proposed NPK seeks to generate knowledge about critical aspects of pharmaceutical quality and failure modes to place it in the public domain and to facilitate accelerated and more confident development and regulatory review of generic products. The paradoxical combination of “new” and “prior knowledge” is chosen deliberately to highlight both a distinction from proprietary and trade secret information and to acknowledge certain historical dogmas inherent in the current practices. Considerations for operationalizing NPK are also summarized.