NIR Spectroscopy and Chemical Imaging of Low Concentration Blends

The distribution of sucrose was evaluated in three different mixtures of sucrose and dextrose using (0.5% Sucrose+ 99.5% Dextrose, 1% Sucrose + 99% Dextrose, 1.5% Sucrose + 98.5 Dextrose). The study was performed to better understand the analysis of these blends by FT-NIR spectroscopy and and NIR-CI (Near Infrared Chemical Imaging). Drug formulations are becoming more potent where low drug quantities have a strong therapeutic effect. Thus, the distribution and mixing of drugs in low concentrations is becoming more important.  All the NIR chemical images were collected with the software Pixys and binary images were prepare in order to identify the different concentration of dextrose in a specific region of the spectra. The data obtained by FT-NIR were analyzed with Pirouette version 4.0 and Origin version 5.0.53 software.  The spectra were pretreated by SNV (Standard Normal Variate), first derivative and second derivative to remove baseline differences. Single point FT-NIR spectra were compared were obtained for all samples and chemical imaging was used to evaluate the distribution of particles in the blends. Single point FT-NIR and PCA (Principal Component Analysis),were not able to fully discriminate between the three mixtures, however, the differences were clearly observed after averaging the spectra obtained. The results clearly show the challenges of analyzing blends where one of the components is at a low level.