Comparison of near-infrared methods for pharmaceutical product drying:: In situ vs. effluent sampling

Previous studies showed how the end point of drying can be determined by using on-line near-infrared (NIR) spectroscopy. These methods either place a probe directly into the dryer in contact with the material being dried or monitor the evolved vapor stream as the drying process proceeds. This report demonstrates the comparability of these methods in detecting the end point of the drying process by measuring both values simultaneously during the drying of a pharmaceutical product.