Under the Microscope: Philip Irving, FOSS NIRSystems Inc.

FOSS NIRSystems, Inc. has a long, complicated and rich history tracing back to 1966 when NEOTEC Corporation was founded. Through a number of acquisitions and mergers, NIRSystems was trademarked in 1989 and bought by Perstorp Analytical, before the company was bought by FOSS in 1997, strengthening the company’s pharmaceutical division.

Although Near Infrared (NIR) technology was discovered in the 19th century, the first industrial applications of the technology began in the 1960s, which Irving ascribes to the advent of small affordable computers. “It not only spurred the development of digital instru – mentation, but also made practical the use of chemometrics, the application of mathematics and statistics to spectroscopic analysis,” Irving surmises. So what exactly is NIR technology? It is a spectroscopic method that uses the near infrared region of the electromagnetic spectrum to analyse samples. NIR can be used on-line, at-line and in-line in the pharmaceutical industry. “For at-line analysis, the NIR analyser is placed near the process,” explains Irving. “The operator then takes a process sample and places it in the NIR analyser. For on-line and in-line analysis, an NIR probe is inserted into the process line. This probe is connected via fibre optics back to the NIR analyser. The difference between on-line and in-line is where in the process the NIR probe is placed. For in-line analysis, the probe is placed directly into the main process pipe, reactor, etc. For on-line analysis, the probe is placed in a sidestream off the main process pipe or reactor.”

“With perhaps the exception of the filterbased instruments, without modern chemo – metric software, NIR would still be used only by a handful academics,” Irving supposes. “NIR chemometric software made it possible to analyse samples containing complex matrices of chemical components without separation or sample preparation. Partial least squares methods coupled with fast personal computers made real-time process measurements possible in-line.”

“Our analysers are involved in the complete process, from incoming raw materials to finished products,” Irving clarifies. “We offer proven digital dispersive NIR analysers, which are fast, accurate and insensitive to vibration.” The benefits of NIR testing are numerous. It is nondestructive and requires no sample preparation. Samples are often measured directly through glass vials, plastic bags or other containers. No hazardous waste is created since NIR requires no solvents or reagents. NIR analysis can reduce the cost of routine testing substantially. The benefits of routine NIR testing include 100 per cent material inspection, improvement in product quality and consistency, and cycle-time reduction.

NIR is used predominantly in solid dosage form manufacturing within the pharmaceutical industry. “Major pharmaceutical manufacturers use NIR to measure content uniformity of active ingredients in capsules and tablets at-line and in the lab. FOSS’s XDS MasterLab can be placed next to a tablet press to ensure the quality of cores and the finished product,” Irving explains. “Other processes that are used for the same product or sample type again and again are good candidates for the time and labour saving of NIR analytical methods. Much work has been done in the biopharmaceutical industry to analyse bioreactors in situ real-time where common parameters such as glucose, lactate, glutamine and glutamate concentrations can be monitored. The creation of dissolution profiles of solid dosage forms based upon the concen tra – tion of release modulators has been published as have hardness and other parameters detected by NIR. Blend uniformity and assay methods have been developed using NIR, providing an alternative to awkward sample thief methods.”

The application of NIR to process monitoring and control has grown over the last decade. The pharmaceutical industry has implemented NIR at-line, on-line and in-line analysis for quality monitoring and closed-loop feedback control. Using statistical process control techniques, processes can be monitored and problems detected and corrected before discrepant material is produced. NIR is particularly well suited to in-line real-time analysis because it can be used with multiplexed fibre optic probes and is robust in industrial environments.

And what of the future for NIR? “The requirement for 100 per cent container inspection for raw material identification has increased interest in NIR ID-testing because it can save hours of wet chemistry lab work,” Irving says. “I also anticipate growth in process applications. In the pharmaceutical industry, NIR process monitoring and control will help to optimise extremely complex process parameters. NIR can measure multiple chemical and physical parameters from each spectrum.”

“From a quality perspective, as pharma – ceutical manufacturers reduce the number of time consuming, labour intensive measure ments, e.g., with HPLC, there will be a greater need for NIR measurements throughout the process stream for quality attributes like blend uniformity and content uniformity,” Irving continues. “In a global sourcing environment, qualitative analysis of raw materials at incoming inspection is increasingly important with the advent of identification of every container demanded by the European Union and Health Canada, and the need for the detection of counterfeit and contaminated products.”