Determination of solvents in compounds of pharmaceutical importance using diffuse reflectance near infrared Fourier transform spectroscopy

Loss on Drying assay (LOD) is the test most used to determine the amount of solvent residues. The assay provides the industry with high precision and accuracy the total amount of solvent residues. This test has the disadvantage that it consumes a long time.; Near infrared spectroscopy makes it possible to analyze pharmaceutical samples using the technique of diffuse reflectance and the method of Partial Least Squares (PLS). This feasibility study has the purpose of evaluating the possibility of determining on-line the concentration of solvent residues in the laboratory.; Pharmaceutical samples and lab-prepared samples were determinate their solvent residues. The pharmaceutical samples contained solvent residues such as methyl tert-butyl ether and water. The samples prepared in the laboratory were obtained adding the ether and were dried before making the assay. The analysis showed a good correlation (R2 > 0.96) between the LOD assay and the method of near infrared to build the calibration curve. The curve is used for determination of solvent residues in the validation samples.