Application Note: In-line Raman spectroscopy for content uniformity

Raman monitoring of blended granule uniformity prior to tablet press…

The U.S. FDA’s Quality by Design (QbD) and Process Analytical Technology (PAT) initiatives encourage the pharmaceutical industry to adopt risk-based manufacturing approaches. Real-time PAT monitoring of pharmaceutical unit operations enables Quality by Design and improves process robustness. Raman spectroscopy is uniquely suited as a PAT tool because it can acquire data directly from the process line in real-time and with little or no sample preparation, often without a need for the probe to come into contact with the sample. The utility of Raman for in-line, real-time process monitoring and control is demonstrated for content uniformity. In this application, in-line, noninvasive Raman spectroscopy was used to monitor blended granule uniformity prior to tablet compression.

Experimental

Raman measurements were obtained during process-validation runs with a RAMANRXNTM analyser utilising PhAT technology from Kaiser Optical Systems. A non-contact Raman PhAT probe (785nm, 6mm spot size, 250mm focal length) mounted onto a Teflon holder was used to monitor the blended granule uniformity just upstream from the tablet press. The Raman probe analysed granule samples of approximately 140mg which correlates closely to the standard dosage unit of 160mg. Raman data were recorded continuously with a 30s exposure time and two accumulations. The mean square of differences (MSD) between two consecutive spectra was used to identify the time required to obtain a homogeneous mixture. The predicted quantitative blend uniformity was determined by Raman analysis of laboratory samples using a two-component partial leastsquares (PLS1) calibration model (RMSEC = 0.43, RMSECV = 0.52). Raman measurements were also collected during tablet compression.