Calibration transfer and maintenance in the pharmaceutical industry: a systematic review

Effective calibration transfer is essential for ensuring accurate and reliable measurements on altering one or more components of spectroscopic measurements, including the spectrometers, sample characteristics, environmental conditions, and measurement settings. Taking a unique perspective, this review aims to provide a guide for pharmaceutical researchers, offering insights into calibration transfer and maintenance applications. The systematic review lists all documented applications of calibration transfer and maintenance algorithms in the pharmaceutical industry up until the time of manuscript preparation. These studies covered various types of calibration transfer scenarios, including intravendor, intervendor, different spectral technologies, and transfers from benchtop to miniaturized instruments. Calibration maintenance cases revealed sources of variation like production scale, temperature changes, sample physical properties, and varied dynamic nature of processes. The review links algorithms to practice while highlighting research gaps. These gaps include limited applications on semi-solid or liquid pharmaceutical products, limited inline applications, and a lack of consensus on best practices. By addressing these shortcomings, this review contributes to advancing calibration transfer in the pharmaceutical industry, supporting precise measurements, improved process control, and the development of high-quality pharmaceutical products.