Application Of Infrared Spectroscopy In Pharmaceutical Analysis

In this paper, near infrared (NIR) spectrometry combined with chemometrics has been applied for quantitative and qualitative analysis of the components in drugs; mid-infrared spectroscopy combined with second derivative, self-deconvolution and curve fitting also has been used for study the changes of the secondary conformation of bovine serum albumin (BSA) when binding with drug molecules, and satisfying results have been obtained. The main contents of the paper are described as follows:1. Determination of three enantiomeric compositions of ehiral compounds by NIR spectrometry and chemometric analysisThe NIR spectrometry combined with partial least squares regression (PLS) was used to determine the D-isomer compositions of ehiral compounds, such as histidine, menthol and tryptophane, discriminated by BSA. The PLS model was compared with principal component regression model and multiple linear regression model. To optimize models, the range of wavenumber and the preprocessing methods were screened, and the parameters were optimized. The results show that NIR spectrometry combined with PLS can correctly predict the D-isomer compositions in the mixture. The accuracy of the model for D-histidine is higher than models for D-menthol and D-tryptophane, this difference may relate to the specific recognition of BSA to ehiral compounds.2. Simultaneous determination of general flavone and polysaccharide in Sophora japonica by NIR spectrometryThe support vector regression (SVR) was applied to construct the mathematic model to correlate near infrared spectral features with the composition of general flavone and polysaccharide, and the results were compared with PLS. The range of wavenumber and the preprocessing methods were screened. The radial basis function was used as kernel function for SVR, the parameters of SVR were optimized by grid search technique. The results show that SVR model performs significantly better than PLS for general flavone; and for polysaccharide determination, the performance of SVR is slightly better than PLS. Compare general flavone and polysaccharide, two kinds of model both show better performance for general flavone.3. Quantitative analysis of nicorandil powder via NIR spectrometryThe NIR spectrometry combined with SVR was used to determine the concentration of nicorandil. Principal component analysis (PCA) and independent component analysis (ICA) were used to compress information. The results show that two methods can both improve the performance of SVR model and can accelerate the speed of modeling. In particular, ICA can improved the performance of SVR model significantly, and made the performance of SVR better than that of PLS.4. Identification of Banlangen Granules from different manufacturers via NIR spectrometryBased on near infrared data of Banlangen Granules, two methods, i.e. clustering analysis and support vector classification (SVC), were used to identification of Banlangen Granules from three different manufacturers. With appropriate preprocessing methods and parameters setting, two methods both can get satisfactory results in proper wavenumber ranges. SVC show better performance than clustering analysis for the accuracy rates of it can get to100%in several wavenumber ranges. The high accuracy also shows that the manufacturing process and product quality of these three manufacturers are stable. Comparing two data collection methods, when the sample slowly rotated in watch glass, the near infrared data is easier to get satisfactory results.5. Study on the interaction of tran-resveratrol and polydatin with BSA by spectroscopyThe fluorescent spectrometry was used to study the interaction of BSA with trans-resveratrol and polydatin respectively and the bonding mechanisms were speculated. The mid-infrared spectra in amide I were processed with second derivative, self-deconvolution and curve fitting methods, the results can used to analyze the changes of protein major secondary structures after interact with trans-resveratrol and polydatin. The results of mid-infrared analysis can assist fluorescent spectrometry to study the interaction mechanisms. Trans-resveratrol and polydatin are all interact with BSA through static quenching procedures, and the procedures happen spontaneously, the interaction made the protein major secondary structures changes. However, the binding constant of trans-resveratrol with BSA is greater than that of polydatin with BSA, and the main interaction forces are different.