Latent variable modeling to assist the implementation of Quality-by-Design paradigms in pharmaceutical development and manufacturing: a review.

The introduction of the Quality-by-Design (QbD) initiative and of the Process Analytical Technology (PAT) framework by the Food and Drug Administration has opened the route to the use of systematic and science-based approaches to support pharmaceutical development and manufacturing activities. In this review we discuss the role that latent variable models (LVMs) can play in the practical implementation of QbD paradigms in the pharmaceutical industry, and the potential they may have in assisting the development and manufacturing of new products. The ultimate scope is to provide practitioners with a perspective on the effectiveness of the use of LVMs in any phase of the development of a pharmaceutical product, from its design up to its commercial production. After an overview of the main regulatory paradigms the QbD initiative is founded on, we show how LVMs can be feasibly used to support pharmaceutical development and manufacturing activities while matching the regulatory Agencies' requirements. Three main areas are identified, wherein the use of LVMs can provide significant benefits: (i) process understanding, (ii) product and process design, and (iii) process monitoring and control. For each of them, the main contributions recently appeared in the literature are reviewed. Issues open for further research are also identified.