A quantitative ¹H nuclear magnetic resonance (qHNMR) method for assessing the purity of iridoids and secoiridoids.

This paper utilized a quantitative (1)H nuclear magnetic resonance (qHNMR) method for assessing the purity of iridoids and secoiridoids. The method was fully validated, including specificity, linearity, accuracy, precision, reproducibility, and robustness. For optimization of experimental conditions, several experimental parameters were investigated, including relaxation delay (D1), scan numbers (NS) and power length (PL1). The quantification was based on the area ratios of H-3 from analytes relative to aromatic protons from 1,4-dinitrobenzene (internal standard) with methanol-d4 as solvent. Five iridoids and secoiridoids (sweroside, swertiamarin, gentiopicroside, geniposide, genipin) were analyzed. Furthermore, the results were validated by the high performance liquid chromatography coupled with ultraviolet detection (HPLC-UV) method. It can be concluded that the qHNMR method was simple, rapid, and accurate, providing a reliable and superior method for assessing the purity of iridoids and secoiridoids.

A universal quantitative ¹H nuclear magnetic resonance (qNMR) method for assessing the purity of dammarane-type ginsenosides.

INTRODUCTION: Quantitative (1)H-NMR (qNMR) is a well-established method for quantitative analysis and purity tests. Applications have been reported in many areas, such as natural products, foods and beverages, metabolites, pharmaceuticals and agriculture. The characteristics of quantitative estimation without relying on special target reference substances make qNMR especially suitable for purity tests of chemical compounds and natural products. Ginsenosides are a special group of natural products drawing broad attention, and are considered to be the main bioactive principles behind the claims of ginsengs efficacy. The purity of ginsenosides is usually determined by conventional chromatographic methods, although these may not be ideal due to the response of detectors to discriminate between analytes and impurities and the long run times involved. OBJECTIVE: To establish a qNMR method for purity tests of six dammarane-type ginsenoside standards. METHODS: Several experimental parameters were optimised for the quantification, including relaxation delay (D1), the transmitter frequency offset (O1P) and power level for pre-saturation (PL9). The method was validated and the purity of the six ginsenoside standards was tested. Also, the results of the qNMR method were further validated by comparison with those of high performance liquid chromatography. CONCLUSION: The qNMR method was rapid, specific and accurate, thus providing a practical and reliable protocol for the purity analysis of ginsenoside standards.

A novel fast disintegrating tablet fabricated by three-dimensional printing.

BACKGROUND: Based on computer-aided models, three-dimensional printing (3DP) technology can exercise local control over the material composition, microstructure, and surface texture during it layer-by-layer manufacturing process to endow the products with special properties. It can be a useful tool in the development of novel solid dosage forms. METHOD: In this study, a novel fast disintegrating tablet (FDT) with loose powders in it was designed and fabricated using 3DP process. The inner powder regions were formed automatically by depositing the binder solutions onto selected regions during the layer-printing processes. RESULTS: Environmental scanning electron microscope images clearly showed that the printed regions were bound together. The particle size was reduced or individual particles could no longer be distinguished. In contrast, the unprinted regions were uncompacted with cracks and fissures among the loose powders. The tablets had a hardness value of 54.5 N/cm(2) and 0.92% mass loss during the friability tests. The disintegration time of the tablets was 21.8 seconds and the wetting time was 51.7 seconds. The in vitro dissolution tests showed that 97.7% acetaminophen was released in the initial 2 min. CONCLUSION: 3DP process is able to offer novel methods for preparing FDTs.