A polychromator-type near-infrared spectrometer with a high-sensitivity and high-resolution photodiode array detector for pharmaceutical process monitoring on the millisecond time scale

Abstract

In the fine chemicals industry, particularly in the pharmaceutical industry, advanced sensing technologies have recently begun being incorporated into the process line in order to improve safety and quality in accordance with process analytical technology. For estimating the quality of powders without preparation during drug formulation, near-infrared (NIR) spectroscopy has been considered the most promising sensing approach. In this study, we have developed a compact polychromator-type NIR spectrometer equipped with a photodiode (PD) array detector. This detector is consisting of 640 InGaAs-PD elements with 20-μm pitch. Some high-specification spectrometers, which use InGaAs-PD with 512 elements, have a wavelength resolution of about 1.56 nm when covering 900-1700 nm range. On the other hand, the newly developed detector, having the PD with one of the world's highest density, enables wavelength resolution of below 1.25 nm. Moreover, thanks to the combination with a highly integrated charge amplifier array circuit, measurement speed of the detector is higher by two orders than that of existing PD array detectors. The developed spectrometer is small (120 mm × 220 mm × 200 mm) and light (6 kg), and it contains various key devices including the high-density and high-sensitivity PD array detector, NIR technology, and spectroscopy technology for a spectroscopic analyzer that has the required detection mechanism and high sensitivity for powder measurement, as well as a high-speed measuring function for blenders. Moreover, we have evaluated the characteristics of the developed NIR spectrometer, and the measurement of powder samples confirmed that it has high functionality.

An identification method for defective tablets by distribution analysis of near infrared imaging

“…7,[24][25][26] We developed a portable NIR imaging device, D-NIRs. 27,28 For an 8 mm tablet sample, D-NIRs can monitor two-dimensional spectra in the 900-1700 nm region within 5 s. D-NIRs' potential as a PAT tool has been discussed in previous studies, [29][30][31] which have demonstrated that the concentration of components in a tablet can be estimated by D-NIRs with high quantitative accuracy. We found that D-NIRs is useful to determine the optimised blending period of pharmaceutical samples.…”

“…P-NIRs has also been developed by our group for process monitoring in the pharmaceutical field. 28 The spectrometer is equipped with a newly developed high-density photodiode array detector of 640 elements with a 20 µm pitch. An indium gallium arsenide (InGaAs) photodiode is used in this spectrometer and has sensitivity in the 900-1700 nm region and can measure a target spectrum in 1.25 nm intervals in that region.…”

“…The characteristics of D-NIRs and its applications have been reported elsewhere. 27,28 Although we have not yet published this information, a 5 s D-NIRs monitoring time has been achieved.…”

Image Monitoring of Pharmaceutical Blending Processes and the Determination of an End Point by Using a Portable Near-Infrared Imaging Device Based on a Polychromator-Type Near-Infrared Spectrometer with a High-speed and High-Resolution Photo Diode Array Detector

“…Our research group has been involved in PAT studies through the development of new NIR instruments, particularly, imaging instruments [15,19,20,21]. We recently developed a distribution type NIR spectrometer (D-NIRs), which is an NIR imaging instrument based on a polychromator-type NIR spectrometer with a high sensitivity and high-resolution photodiode array detector (PDA).…”

Recent Progress of Near-Infrared (NIR) Imaging —Development of Novel Instruments and Their Applicability for Practical Situations—

“…22,23 Although conventional NIR spectrometers are generally equipped with an InGaAs-photodiode (PD) array that has 256 or 512 elements, P-NIRs is equipped with a PD array that has 640 elements. P-NIRs, therefore, can measure spectra in the 900 -1700 nm region with a wavelength resolution of 1.25 nm.…”