Yang Lu

Development of a new certified reference material of diosgenin using mass balance approach and Coulometric titration method

Certified reference materials (CRMs) can be used as a valuable tool to validate the trueness of measurement methods and to establish metrological traceability of analytical results. Diosgenin has been selected as a candidate reference material. Characterization of the material relied on two different methods, mass balance method and Coulometric titration method (CT). The certified value of diosgenin CRM is 99.80% with an expanded uncertainty of 0.37% (k=2). The new CRM of diosgenin can be used to validate analytical methods, improve the accuracy of measurement data and control the quality of diosgenin in relevant pharmaceutical formulations.

Purity determination and uncertainty evaluation of a new certified reference material of Pinocembrin

This study introduces a purity determination and uncertainty evaluation method for a new certified reference material (CRM) of Pinocembrin (GBW09554), using a mass balance method and differential scanning calorimetry (DSC). Sample preparation, homogeneity and stability studies, value characterization, and evaluation of uncertainty of a new CRM of Pinocembrin are presented in this paper. The homogeneity and stability are checked using a mass balance method and the stability is tested under different storage conditions. The CRM described above was found to be homogeneous and stable at 25 °C for at least one year. The certified value of Pinocembrin CRM is 99.7% with an extended uncertainty of 0.5% (k = 2). A DSC method is used for purity determination of Pinocembrin for the first time in this paper. The new CRM of Pinocembrin can be used to validate analytical methods, improve the accuracy and comparability of measurement data, establish meteorological traceability of analytical results as well as control the quality of Pinocembrin in relevant food and pharmaceutical formulations.

8-Meth­oxy-3,4-methyl­enedi­oxy-10-nitro­phenanthrene-1-carboxylic acid

In the crystal structure of the title compound, C17H11NO7, the phenanthrene ring system and the five-membered ring are almost coplanar. The carbxadoxy and nitro groups lie above and below the plane, respectively, owing to steric effects. The hydrxadoxy groups form strong interxadmolecular O—H⋯O hydrogen bonds with the carbonyl group O atom. The carbxadoxy groups of pairs of molecules form centrosymmetric rings via pairs of interxadmolecular hydrogen bonds.

Study on four polymorphs of bifendate based on X-ray crystallography.

Bifendate, a synthetic anti-hepatitis drug, exhibits polycrystalline mode phenomena with 2 polymorphs reported (forms A and B). Single crystals of the known crystalline form B and 3 new crystallosolvates involving bifendate solvated with tetrahydrofuran (C), dioxane (D), and pyridine (E) in a stoichiometric ratio of 1:1 were obtained and characterized by X-ray crystallography, thermal analysis, and Fourier transform infrared (FT-IR) spectroscopy. The differences in molecular conformation, intermolecular interaction and crystal packing arrangement for the four polymorphs were determined and the basis for the polymorphisms was investigated. The rotation of single bonds resulted in different orientations for the biphenyl, methyl ester and methoxyl groups. All guest solvent molecules interacted with the host molecule via an interesting intercalative mode along the [1 0 0] direction in the channel formed by the host molecules through weak aromatic stacking interactions or non-classical hydrogen bonds, of which the volume and planarity played an important role in the intercalation of the host with the guest. The incorporation of solvent-augmented rotation of the C–C bond of the biphenyl group had a striking effect on the host molecular conformation and contributed to the formation of bifendate polymorphs. Moreover, the simulated powder X-ray diffraction (PXRD) patterns for each form were calculated on the basis of the single-crystal data and proved to be unique. The single-crystal structures of the four crystalline forms are reported in this paper.

Development of new reference material neohesperidin for quality control of dietary supplements.

BACKGROUNDnNeohesperidin is an important natural flavanone glycoside distributed in several citrus species. This compound is widely used as a raw material for food additives in the food industry. The request for certified reference materials (CRMs) in dietary supplements was stipulated by the National Administrative Committee for CRMs and was underpinned by the need to improve the accuracy and comparability of measurement data and to establish metrological traceability of analytical results.nnnRESULTSnThis paper reports the sample preparation methodology, homogeneity and stability studies, value assignment and uncertainty estimation of a new certified reference material of neohesperidin (GBW09522). Differential scanning calorimetry, coulometric titration and mass balance methods proved to be sufficiently reliable and accurate for certification purposes. The certified value of neohesperidin CRM is 994 g kg(-1) with an expanded uncertainty of 4 g kg(-1) (k = 2). The reference material described above was homogeneous and stable for 12 months at a storage temperature of 25 °C.nnnCONCLUSIONnThe new CRM of neohesperidin can be used to validate analytical methods and improve the accuracy of measurement data as well as quality control of neohesperidin-related dietary supplements, foods, traditional herbs and pharmaceutical formulations.

A host–guest 1:2 inclusion compound of 1,1,6,6-tetra­phenyl­hexa-2,4-diyne-1,6-diol and 4-methoxy­benz­aldehyde

The inclusion method was used to isolate a single component from a volatile oil mixture (extracted from the natural medicine, fructus foeniculi) with 1,1,6,6-tetraxadphenylxadhexa-2,4-diyne-1,6-diol as the host molxadecule and 4-methoxyxadbenzxadaldehyde as the guest (an oil mixture component). Crystals of the host–guest inclusion complex were obtained as C30H22O2·2C8H8O2, with the host molxadecule residing on a crystallographic inversion centre and connected to the guest molxadecule by an intermolecular hydrogen bond [O⋯O = 2.846u2005(5)u2005A]. The host–guest molxadecules form a layer-type structure, which extends along the a axis and periodically arranges along the b axis.

Development of a New Certified Reference Material of Kaempferol by Using Differential Scanning Calorimetry, Coulometric Titration Method, and Mass Balance Method

AbstractDietary flavonols have been found to possess preventive and therapeutic potential against several kinds of cancers. According to epidemiologic investigation data, kaempferol is a major component of flavonols present in various natural sources such as herbs, vegetables, and fruits. The purity of kaempferol in candidate certified reference material (CRM) was based on the agreement of results obtained by three different methods, including differential scanning calorimetry (DSC), coulometric titration (CT), and mass balance method. The certified value of kaempferol CRM is 99.5xa0% with an expanded uncertainty of 0.2xa0% (ku2009=u20092). The new CRM of kaempferol can be used as a valuable tool to validate measurement methods, to evaluate analytical results, and to control the quality of kaempferol-related traditional herbs, foods, dietary supplements, and pharmaceutical formulations.n Graphical AbstractDevelopment of a New Certified Reference Material of Kaempferol

Certification of a new certified reference material of honokiol

Honokiol is the most important active pharmaceutical ingredient in Magnolia officinalis, which is a famous traditional Chinese medicine and commonly used in clinical practice. In order to control the quality of honokiol and related pharmaceuticals, a new certified reference material (CRM) of honokiol was developed. The studies of sample preparation, homogeneity, stability, value assignment, and uncertainty evaluation were accomplished in this paper. Three different methods, including differential scanning calorimetry (DSC), mass balance method (MB), and coulometric titration (CT), were employed to determine the purity of honokiol. Specifically, the DSC and CT methods for purity determination of honokiol were established for the first time. The purity of honokiol CRM, after validation and evaluation, was found to be 99.3xa0%, with an expanded uncertainty of 0.5xa0% (ku2009=u20092).

Quantitative analysis of trace level asbestos in pharmaceutical talc by powder X-ray diffraction

As a traditional Chinese medicine and excipient, talc is widely used in medical and pharmaceutical fields. It may be contaminated with asbestos (including tremolite and chrysotile). Asbestos is known to be a carcinogen and it can cause lung cancer. Therefore, it is important to determine the concentration of asbestos in talc. This paper reports the use of powder X-ray diffraction (PXRD) technology to establish a trace level concentration detection of asbestos in traditional medicinal talc at 0.3 to 0.8%. The results show that the method is reliable, sensitive and suitable for its intended use of detecting trace levels of asbestos in the talc. Among the fifty-four talc samples, nine of them were found to contain asbestos and were disqualified. The passing rate of the test is 83.3%, which means it is necessary to establish an effective method to determine trace level asbestos in talc.

2a,3a-Dihydroxy­androstan-16-one

The title compound, C19H28O4, is a new androstane steroid derivative. In the crystal, molecules are linked along the a axis by intermolecular O—H⋯O hydrogen bonds.