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In this work, an integrated PAT approach was developed for monitoring a pharmaceutical (naproxen) and a polymer (eudragit) coprecipitation process: real-time in-line near-infrared (NIR) absorbance monitoring, real-time on-line turbidity monitoring, and in situ crystal size monitoring. The data and information obtained through these three monitoring techniques confirmed the observation of the onsets of three distinct stages: incubation, nucleation, and crystal growth. The process trajectory constructed based on results of applying principal component analysis (PCA) to either process NIR spectra data or process turbidity profile, clearly demonstrated that various distinguishable process events, including incubation, nucleation, and crystal growth, could be accurately tracked and differentiated. These findings were further supported by process knowledge and information, such as process design, process sequence, thermodynamic and mass-transfer analysis. Therefore, this work provides a case study that illustrated a rational approach to develop a science-based and knowledge-based process monitoring strategy, which is essential for establishing both a suitable process control strategy and an operational process space for a pharmaceutical unit operation. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1516–1534, 2010 [ABSTRACT FROM AUTHOR]

The objective of this study was to develop an integrated process monitoring approach for evaluating powder blending process kinetics and determining blending process end-point. A mixture design was created to include 26 powder formulations consisting of ibuprofen as the model drug and three excipients (HPMC, MCC, and Eudragit L100-55). The mixer was stopped at various time points to enable near-infrared spectroscopy scan of the powder mixture for obtaining the time course of the blending process. The evaluation of the blending process kinetics and process end-point was studied through three quantitative approaches: (1) Spectra linear superposition method; (2) Characteristic peak method; (3) Moving block standard deviation method. It was found that the powder blending experienced an initial rapid process to reach a quasi- end point within the first few minutes. Afterwards, a demixing occurred. Then, a real blending end-point was reached as characterized by an inflection point. ANOVA shows that the compositions of ibuprofen and MCC are the most statistically significant variables that impact the time required to reach the blending end-point. This highlighted the critical importance of developing quantitative chemometric approaches to extract critical process information and generate essential process knowledge to enable real-time release of the blending process. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2784–2798, 2009 [ABSTRACT FROM AUTHOR]