Finally, Dr. Colon-Rivera discussed microextraction as a means of sample enrichment using either small volumes of, or no organic solvents, with no need for further concentration. These techniques—such as solid-phase microextraction, liquid phase microextraction, and microextraction in packed syringe—are fast, simple, some of them disposable, and cost-effective, Dr. Colon-Rivera said.
Bristol-Myers Squibb’s Gary McGeorge spoke in the conference on “Applications of chemical imaging,” a technique that has enjoyed rapid growth over the past decade as the required imaging and computer equipment has become widely available and robust computational software has been developed.
The technique provides both chemical information (spectra) and spatial information. For example, when molecules of a drug crystallize from solution, Raman spectra may show differences due to crystal structure variations, indicating polymorphism that can change pharmaceutical activity. Bristol-Myers Squibb also looks at images of blends during the blending process to measure performance.
A fundamental premise of chemical imaging, McGeorge told the conference, is that the relative location of components can be critical to pharmaceutical performance. Imaging of tablets can determine if aggregates of API influence the dissolution profile, measure the API particle size distribution, correlate laser line scan data with near infrared (NIR) image data, provide indices that can be used to describe spatial distribution and correlate these to dissolution characteristics, and determine why and how agglomerates influence the dissolution profile by imaging water uptake/ingress in situ.