Analysis of residual moisture in a lyophilized pharmaceutical product by near-infrared spectroscopy

This Application Bulletin describes an approach for developing near-infrared methods for the determination of residual moisture in typical lyophilized pharmaceutical products. In this case, samples were contained in sealed 30 mL serum vials (3 cm o.d.). The average cake weight of this product was 1.6 g with a target moisture level of 1% and acceptable moisture limit of not more than 2% by weight. A calibration sample set was prepared by spiking sample vials with varying amounts of water. Diffuse reflectance nearinfrared spectra of these calibration samples were acquired and multiple linear regression (MLR) algorithms applied to correlate spectral changes to experimentally measured moisture values as determined by Karl Fischer titration.