Application of Quality by Design Principles for the Definition of a Robust Crystallization Process for Casopitant Mesylate

Abstract

GlaxoSmithKline (GSK) has identified casopitant as a potent NK1 antagonist. It was selected for its potential activities on a number of therapeutic targets such as inflammatory bowel disease, overactive bladder, CNS disorders and others. The mesylate salt of casopitant was selected for full development using a quality by design (QbD) approach in which a control strategy was developed from a design space, underpinned by process understanding and risk analysis for an enhanced level of quality assurance. As the concepts of design space and control strategy in the QbD framework move on from their inception to implementation, the ambiguity of definition has led to considerable discussion, diversity of opinions and uncertainty around how best to define these ideas. This contribution provides an outline of the sequential experimentation and analyses that led to the construction of a Bayesian approach to the ICH Q8 definition of Design Space. This uses a predictive approach for multiple response surface optimisat...