Multivariate model for in-line monitoring of moisture content in a high shear mixer using near infrared spectroscopy

Abstract

Wet granulation process in a high shear mixer is a complex unit operation widely used in the pharmaceutical and food industry where moisture content is a critical factor since it affects the growth of granules or particles. The granule size affects flow ability, drug delivery, and tablet hardness; therefore, it is important to monitor and to control the quantity of liquid in the mixer. In this work a mixer was equipped with a near infrared (NIR) spectrometer to monitor the moisture content during granulation. Initially, pharmaceutical excipients were homogenized in a mixer. Next, water was added to the powder mixture to initiate wet granulation, and NIR spectra were collected each minute. The aim of this work was to evaluate the near infrared spectroscopy as an in-line technique for monitoring the moisture content of pharmaceutical powders during wet granulation process in a laboratory-scale high shear mixer. The results confirm the ability of NIR spectrometer to take full in-line and off-line spectra of pharmaceutical powders at different levels of added binder. The multivariate model developed for determining the in-line spectra variation during granulation was capable of measuring the moisture content with high precision (0.207% w/w).