A novel approach to determine water content in DMSO for a compound collection repository

The quality of a corporate compound collection can be significantly affected by a complex combination of storage and operational processing factors. Water content in DMSO solutions is one factor that is of great interest as it can affect solubility, degradation, and freeze-thaw cycle parameters. To the authors' knowledge, this is the first report of using near-infrared (NIR) spectroscopy to assess water content in DMSO compound stock solutions within the common storage vessel format of polypropylene microtubes. The precision and accuracy of the NIR technique was benchmarked against a Karl Fisher titration method, and a correlation coefficient was determined to be 0.985 over a range of 1% to 10% water in DMSO by weight. The advantages of the NIR technique include accuracy, precision, speed, nondestructiveness, and the capability of assessing compounds under in situ storage conditions within microtubes. In this report, the authors demonstrate the accuracy and precision of using NIR to assess water content in DMSO solutions and present a case study to demonstrate the utility of the technique to aid in assessing a pharmaceutical compound collection.