NMR is a well-established and powerful technique for elucidating molecular structures, determining degradation products/impurities and studying molecular dynamics. As such, NMR is routinely used in pharmocokinetic studies, drug metabolism and organic synthesis and natural product chemistry. Methods based on NMR can also be employed to analyze mixtures without physical separation, and measure molecular properties and bulk properties of the medium.
Process inputs can be readily verified against standard formulations before they are introduced into the process. This minimises waste and allows production processes to be optimised. Liquid materials can be fed automatically through the NMR system located on the production line, enabling rapid and continuous sampling. This will help to maximise plant utilisation and provides near-real time feedback for adjustment of process parameters and fits in well with PAT.
High sensitivity can be achieved by integrating LC with NMR. Analysing the fractions has the added advantage that no references are required and there will also be fewer peaks in the spectra making it easier to detect possible contamination or other undesirable components.
In line application need not be limited to production plants. In-line monitoring of reactions during the development process can minimise development time as reactions can be curtailed immediately when it is clear the reaction is not progressing as desired. Later NMR can be used in pilot plants to optimise production parameters.