Zhou X, Hines P, Borer M W
Eli Lilly and Company, Lilly Research Laboratories, Indianapolis, IN 46285, USA.
J Pharm Biomed Anal. 1998 Jun;17(2):219-25. doi: 10.1016/s0731-7085(97)00182-9.
The moisture level in a hygroscopic drug substance was successfully determined by near infrared spectroscopy using coulometric Karl Fischer titration as the reference method. The importance of sample handling and proper application of the reference technique are stressed for this difficult sample type. Samples were prepared with moisture levels from 0.5 to 11.4% (w/w) and reflectance spectra were collected over the spectral range 1100-2500 nm. Calibration models were built using partial least squares (PLS) regression analysis. Optimum models were found by choosing proper spectral ranges and number of PLS factors. The best calibration models were built using first derivative spectra, a spectral range of 1850-1936 nm and 5 PLS factors. The corresponding standard error of prediction was 0.11% (w/w) water.
采用库仑卡尔费休滴定法作为参考方法，通过近红外光谱法成功测定了吸湿性药物中的水分含量。对于这种难处理的样品类型，强调了样品处理和参考技术正确应用的重要性。制备了水分含量为0.5%至11.4%（w/w）的样品，并在1100 - 2500 nm光谱范围内收集反射光谱。使用偏最小二乘法（PLS）回归分析建立校准模型。通过选择合适的光谱范围和PLS因子数量找到最佳模型。使用一阶导数光谱、1850 - 1936 nm的光谱范围和5个PLS因子建立了最佳校准模型。相应的预测标准误差为0.11%（w/w）水。
