Investigation of the Variability of NIR In-line Monitoring of Roller Compaction Process by Using Fast Fourier Transform (FFT) Analysis

Abstract

Abstract. The purpose of this research was to investigate the variability of the roller compaction process while monitoring in-line with near-infrared (NIR) spectroscopy. In this paper, a pragmatic method in determining this variability of in-line NIR monitoring roller compaction process was developed and the variability limits were established. Fast Fourier Transform (FFT) analysis was used to study the source of the systematic fluctuations of the NIR spectra. An off-line variability analysis method was developed as well to simulate the in-line monitoring process in order to determine the variability limits of the roller compaction process. For this study, a binary formulation was prepared composed of acetaminophen and microcrystalline cellulose. Different roller compaction parameters such as roll speed and feeding rates were investigated to understand the variability of the process. The best-fit line slope of NIR spectra exhibited frequency dependence only on the roll speed regardless of the feeding rates. The eccentricity of the rolling motion of rollers was identified as the major source of variability and correlated with the fluctuations of the slopes of NIR spectra. The off-line static and dynamic analyses of the compacts defined two different variability of the roller compaction; the variability limits were established. These findings were proved critical in the optimization of the experimental setup of the roller compaction process by minimizing the variability of NIR in-line monitoring.

Evaluation of Three Approaches for Real-Time Monitoring of Roller Compaction with Near-Infrared Spectroscopy

“…The interest in understanding the effect of operating parameters and material properties has also lead to research efforts for real-time monitoring of ribbon density, where nearinfrared spectroscopy (NIRS) has been the principal analytical technique used (12)(13)(14)(15). Real-time monitoring with subsequent control of roller compaction parameters is being followed to minimize the effects of density variation and control the properties of manufactured tablets.…”

Process Analytical Technology for continuous manufacturing of solid-dosage forms

“…The fact that dust and the rather low detection sensitivity might lead to inconsistent collection of in-line NIR spectra was also recognized by Feng et al [27]. They determined the sources of variability in in-line collected NIR spectra during roller compaction (i.e., motion of the rollers) and designed a new in-line control kit.…”

Application of Near-Infrared Spectroscopy in Real-Time Monitoring of Product Attributes of Ribbed Roller Compacted Flakes

“…9d) of the flakes. Variations between these offline and real-time spectral data could be attributed to the effect of 3 days relaxation time and temperature effect (15).…”

“…Several nondestructive monitoring techniques have been reported for monitoring the roller compaction process and they include acoustic relaxation emissions from compacted powder (12)(13)(14), thermal effusivity (9), and near-infrared (NIR) spectroscopy (15)(16)(17). Among these methods, NIR spectroscopy has gained the most interest due to its many advantages.…”

“…There have been considerable reports on the successful application of NIR for in-line monitoring of the roller compaction process (15,16). Gupta et al reported that content uniformity, density, and tensile strength (TS) of the flakes could be predicted in-line with appropriate design of experiments and calibration model (16,18).…”