| Near infrared (NIR) diffuse reflectance spectrometry has aroused special interest in the pharmaceutical industry, due to its suitability for qualitative and quantitative determination of physical and chemical parameters, its ability to analyze solid samples with minimal or no manipulation and its compatibility with fiber optic probes as signal transmitters, which facilitates analyses.; In this work, NIR diffuse reflectance spectroscopy with a fiber optic probe was used for the determination (qualitative and quantitative) of residual solvents in an active pharmaceutical ingredient. The qualitative analysis was performed using Mahalanobis distance as criteria of pass or fail test. Partial least square (PLS) algorithm was used for quantitative analysis. The influences of the spectral mode and wavenumber range used are studied.; Qualitative and quantitative analyses demonstrated that the minimum amount of isopropyl alcohol found was 0.95% w/w. Although the analyses are carried out near the limit of quantitation of the instrument, the standard error of prediction obtained was 0.03% w/w. |
