Special Issues-08-01-2011
Using Real-Time FT-IR to Characterize UV Curable Optical Adhesives
August 1st 2011When combined with the rapid scan speeds of modern instruments, Fourier-transform infrared (FT-IR) spectroscopy provides a powerful real-time method for monitoring chemical changes (for example, the optical adhesive caused by illumination of a UV lamp). This article describes the characterization of several adhesives used in an optical assembly. Several different approaches to measuring the rate of change during the curing experiment are described. As the number of uses for UV curing and photopolymerization increases, real-time FT-IR should play a major role in characterizing these new materials and products.
NIR Monitoring of a Hot-Melt Extrusion Process
August 1st 2011Process analytical technology (PAT) and hot-melt extrusion (HME), commonplace in the food and polymer industries, are becoming increasingly deployed in the pharmaceutical industry. Herein the application of in-line, transmission mode, Fourier-transform near-infrared (FT-NIR) spectroscopy to the HME manufacturing platform for a drug product in development is detailed. NIR spectroscopy and partial least squares (PLS) models were developed for real-time active pharmaceutical ingredient (API) loading (%wt/wt) and surfactant loading predictions. These predictions were used for fault detection, isolation of suspect material, and real-time troubleshooting during HME. Additionally, the NIR/PLS output was used for real-time release of the intermediate drug product.
Contact and Orientation Effects in FT-IR ATR Spectra
August 1st 2011In recent years, attenuated total reflection (ATR) spectroscopy has become the preferred method for many routine infrared (IR) measurements. However, the simplicity of the technique has made it available to users who may not be aware of some effects that significantly influence the appearance of ATR spectra. This results in changes to the relative intensities of different absorption bands. The aim of this article is to explain the origin of these effects and to provide examples. In particular, it will focus on those effects that are not evident from inspection of the spectra.
