ABSTRACT
Pharmaceutical companies and regulatory agencies have more and more concerns for impurities in pharmaceuticals and their toxicity. In this work, heart-cutting two-dimensional ultrahigh-performance liquid chromatography (2D-UHPLC) in combination with high-resolution mass spectrometry (HRMS) was used, setting HRMS as positive mode of electrospray ionization to identify five impurities in pioglitazone hydrochloride preparations. With the heart-cutting 2D-UHPLC and online desalting technique, the structures of five impurities were deduced in an analysis of MSn data. And three of them, Impurity-2, Impurity-3, and Impurity-5, have never been reported before. The fragmentation patterns of five impurities were proposed on a basis of accurate mass and fragment ions in this study. Since the toxicity of impurities is relevant to their structures, toxicology of all five impurities was predicted by three software tools, and the result showed that these compounds have good safety profile.
ABSTRACT
Cuttlefish, a unique group of marine mollusks, produces an internal biomineralized shell, known as cuttlebone, which is an ultra-lightweight cellular structure (porosity, â¼93 vol%) used as the animal's hard buoyancy tank. Although cuttlebone is primarily composed of a brittle mineral, aragonite, the structure is highly damage tolerant and can withstand water pressure of about 20 atmospheres (atm) for the species Sepia officinalis Currently, our knowledge on the structural origins for cuttlebone's remarkable mechanical performance is limited. Combining quantitative three-dimensional (3D) structural characterization, four-dimensional (4D) mechanical analysis, digital image correlation, and parametric simulations, here we reveal that the characteristic chambered "wall-septa" microstructure of cuttlebone, drastically distinct from other natural or engineering cellular solids, allows for simultaneous high specific stiffness (8.4 MNâ m/kg) and energy absorption (4.4 kJ/kg) upon loading. We demonstrate that the vertical walls in the chambered cuttlebone microstructure have evolved an optimal waviness gradient, which leads to compression-dominant deformation and asymmetric wall fracture, accomplishing both high stiffness and high energy absorption. Moreover, the distribution of walls is found to reduce stress concentrations within the horizontal septa, facilitating a larger chamber crushing stress and a more significant densification. The design strategies revealed here can provide important lessons for the development of low-density, stiff, and damage-tolerant cellular ceramics.
Subject(s)
Biomimetic Materials/chemistry , Bone and Bones/chemistry , Sepia/chemistry , Animals , Biomechanical Phenomena , Ceramics/chemistry , Equipment Design , Hardness , PorosityABSTRACT
A HPLC-FLD method has been developed and validated for zearalenone (ZON) in 107 widely consumed Chinese medicinal herbs and related products collected from different regions of China. Samples were extracted with methanol/water (80 : 20, v/v), and the extracts were cleaned-up through immunoaffinity columns (IAC). ZON was quantified by HPLC with fluorescence detection. Recoveries from three different medicinal herbs spiked with ZON at levels ranging from 30 to 600 µg kg(-1) were from 80.8 to 98.3%. The limit of detection was 9.5 µg kg(-1), based on a signal-to-noise ratio of 3 : 1. Naturally occurring ZON was only found in coix seed medicinal herb (all nine samples), with levels ranging from 18.7 to 211.4 µg kg(-1). Positive results were confirmed by UV spectrum and LC-ESI-MS/MS. This is the first report of ZON contamination of a Chinese medicinal herb.
Subject(s)
Chromatography, High Pressure Liquid/methods , Drug Contamination , Drugs, Chinese Herbal/analysis , Estrogens, Non-Steroidal/analysis , Zearalenone/analysis , Animals , China , Coix/chemistry , Coix/toxicity , Drugs, Chinese Herbal/toxicity , Estrogens, Non-Steroidal/toxicity , Humans , Limit of Detection , Spectrometry, Fluorescence , Spectrometry, Mass, Electrospray Ionization , Spectrophotometry, Ultraviolet , Tandem Mass Spectrometry , Zearalenone/toxicityABSTRACT
OBJECTIVE: To provide scientific basis for the utilization and development of Herba Justiciae by setting up the quality control specification of Herba Justiciae. METHOD: Moisture and ash were determined by aquametry and method of ash determination. And the bioactive constituents were analyzed by HPLC. RESULT: The contents of total ash, acid-insoluble ash, and moisture of 28 samples from different origins were determined. The quantitative analysis of chinensinaphthol methyl ether by HPLC were preformed, respectively. CONCLUSION: The established method can be used for the quality control of Herba Justiciae.
