Real-time determination of blend uniformity in veterinary products using near infrared (NIR) spectra

This study presents a new multivariate analytical strategy for real-time assessment of blend uniformity in powder mixtures using Near Infrared Spectroscopy (NIRS) as a Process Analytical Technology (PAT). The proposed method, called the Intensity Ratio (IR), monitors spectral variability at selected wavelengths corresponding to the excipient and the Active Pharmaceutical Ingredient (API). The approach was compared to established statistical strategies, including Relative Standard Deviation (RSD), F-test, Standard Deviation (SD), PC Score Distance Analysis (PC-SDA), and Conformity Index (CI).

For this study, a binary mixture of an active pharmaceutical ingredient (API) and excipient, together with three industrial batches used as Golden Batch (GB), according to the rationale for the number of batches for different residual risk levels described on Stage 2, ISPE [1] have been used to build the model, where the uniformity of the mixture has been determined at a predefined time and the analysis has been carried out using the reference technique, High Performance Liquid Chromatography (HPLC).

These findings suggest that PAT-based strategies can improve efficiency in pharmaceutical manufacturing by enabling real-time blend uniformity assessment, potentially reducing both process time and cost. The IR method, in particular, offers a robust and fast alternative when a characteristic API absorption peak can be reliably monitored.