Content uniformity and tablet hardness testing of intact pharmaceutical tablets by near infrared spectroscopy: A contribution to process analytical technologies

The use of process analytical technologies by the pharmaceutical industry is a response to its growing need for improved productivity in order to face the increasing competition in this field. In this work, we explored the use of near infrared spectroscopy (NIRS) for the determination of physical (tablet hardness) and chemical parameters (active principle and content uniformity) in intact individual pharmaceutical tablets. Quantization was done by using a Partial Least Squares 1 (PLS1) calibration model constructed from laboratory calibration samples that were prepared by mixing the active principle and excipients, and pressing the mixture into tablets. The compaction pressure to be applied to the powder was previously determined by using another PLS1 model that allows calculating it from production tablets. The NIRS method used to quantify the active principle is simpler as the calibration set encompasses the variability sources present in production samples; also, it allows individual tablets to be analysed. The proposed method was validated in accordance with the International Conference on Harmonization (ICH) and The European Agency for the Evaluation of Medicinal Products (EMEA) guidelines, and found to be fit for its intended purpose.