NMR ushers in new check weighing era

A new weighing system developed by BOC Edwards Pharmaceutical systems can be used in a pharmaceutical filling line but does not come into contact with the weighed materials.

The product, claimed to be the first non-contact check-weighing system to be used in this application, was developed for a major US pharmaceutical company. It uses nuclear magnetic resonance (NMR) technology and is said to allow increased quality control and efficiency.

Traditional methods of weighing on high-speed filling lines involve samples being periodically removed from the line and weighed on precision balances, both before and after filling. The new Non-Contact Check Weigher (NCCW) is incorporated into the filling line, so that every container is checked as it continues through the production process.

Any problems with the process are identified virtually immediately and corrected via process feedback to the BOC Edwards filling equipment - a real-time approach that lies at the heart of the US Food and Drug Administration (FDA)'s recently unveiled Process Analytical technology (PAT) initiative.

This reactive approach "greatly reduces the costs of waste product and downtime and providing greater assurance that each individual vial contains the correct amount," according to BOC Edwards.

NMR technology measures the magnetic properties inherent in atomic nuclei; the signal received from the MR system being proportional to the number of hydrogen atoms contained in the sample and hence also the mass of the sample. Although the technology is novel for this pharmaceutical application, NMR has already proved to be highly accurate and reliable within other industries, for example in diagnostic medical imaging and quality measurements of samples from oil wells.

"The pharmaceutical industry is under increased pressure to improve process monitoring and control while maintaining extremely high levels of throughput," explained Dr Paul Stewart, director of technology at BOC Edwards.

"I believe is the most significant innovation in check-weighing for over 50 years," he added.