In-line quantification of two active ingredients in a batch blending process by near-infrared spectroscopy: influence of physical presentation of the sample.

The aim of this study was to apply near-infrared (NIR) spectroscopy to the simultaneous in-line monitoring of two active pharmaceutical ingredients (APIs) in a pharmaceutical batch blending process. The formulation under study consisted of a high load API (A1), one polymer, a second API (A2) and one lubricant. Additionally, the effects of the presentation of A1 on the spectral data were evaluated. For this purpose, the high load active was blended either as a cohesive powder or as a free flowing material. For improving the flow behavior of the high load active a melt-granulation (MG) step was performed. The NIR spectra of the high load API (A1) before and after MG showed that the polymer wavelength absorption band was the most affected, this wavelength range was also associated with the water band region. Thus, these frequencies carried information from the melt-granulation process and could be influenced by the water content. For the APIs quantification, independent partial least squares (PLS-1) models for each API were generated. Furthermore, a PLS-2 model was also developed for the simultaneous quantification of each API. The PLS models were used for the in-line blend uniformity monitoring of both APIs.