Identification of the differentiation for substitution poly-dispersions of hydroxypropyl-β-cyclodextrins by spectroscopy characteristics

OBJECTIVE To study the differences of the nuclear magnetic resonance hydrogen spectrum(¹H-NMR) and Fourier transform infrared spectroscopy(FTIR) of hydroxypropyl-β-cyclodextrin(HP-β-CD), provide a basis for establishing a new quality evaluation method for HP-β-CD with discriminative power. METHODS Nine batches of HP-β-CD from Roquette were selected as the original products. After preprocessing the data, combined with hierarchical clustering analysis(HCA) and principal component analysis(PCA) stoichiometry methods, the HP-β-CD recognition model was established to study the classification of HP-β-CD. On the other hand, 18 batches of HP-β-CD from 3 domestic companies were collected as imitations and processed similarly. The data were analyzed in comparison with original products, and their species belonging status were observed for quality evaluation. RESULTS PCA results of NMR data showed that 9 batches of original products were divided into 3 categories, and there was no correlation with the average degree of substitution, but there were significant differences between products with the degree of substitution. The 18 batches of imitation products were divided into 4 categories, which were not completely related to the manufacturer and the degree of substitution, and there were distant batches that did not belong to any category. PCA results of FTIR data showed that 9 batches of original research products were divided into 4 categories, and all samples were divided into 3 categories together. There were discrete batches, and each category contained both original research products and imitations. Under the two methods, HP-β-CD was not completely separated according to the average degree of substitution or the manufacturer's standard, indicating that the substitution behavior of HP-β-CD had the characteristics of poly-dispersity. Although they all met the regulatory requirements, there were differences in the intrinsic quality of different batches. CONCLUSION The stoichiometric analysis based on NMR and FTIR spectral characteristics, the analysis of spectroscopy characteristics is of great significance to the quality evaluation of HP-β-CD and the optimization of imitation products.