LC‐MS/MS analysis of Gegen Qinlian Decoction and its pharmacokinetics after oral administration to rats

A liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method was developed and validated for the simultaneous determination of 12 constituents of Gegen Qinlian Decoction (GQD), namely puerarin, daidzein, baicalin, wogonoside, wogonin, liquiritin, liquiritigenin, berberine, jatrorrhizine, palmatine, coptisine and glycyrrhetic acid, in rat plasma. The plasma samples were spiked with the internal standard (IS) carbamazepine acidified with HCl and extracted by liquid–liquid extraction with ethyl acetate. Chromatographic separation was achieved on a Shiseido Capcell PAK C₁₈ column utilizing a gradient elution profile and a mobile phase consisting of (A) 0.1% formic acid in water and (B) acetonitrile. Detection was performed in the multiple reaction monitoring mode using electrospray ionization in the positive ion mode at a flow rate of 0.3 mL/min and a run time of 8 min. All of the calibration curves gave good linearity (r > 0.9930) over the concentration range from 0.6–360 to 16.2–9720 ng/mL for all components. The intra‐ and inter‐day precisions were <15.0% in terms of the relative standard deviation, and the accuracies were within ±13.7% in terms of the relative error. The method was successfully applied to investigate the pharmacokinetics of the major active compounds of Gegen Qinlian Decoction after its oral administration to rats. Copyright © 2014 John Wiley & Sons, Ltd.     

Yolk‐Shell Porous Microspheres of Calcium Phosphate Prepared by Using Calcium L‐Lactate and Adenosine 5′‐Triphosphate Disodium Salt: Application in Protein/Drug Delivery

A facile and environmentally friendly approach has been developed to prepare yolk‐shell porous microspheres of calcium phosphate by using calcium L ‐lactate pentahydrate (CL) as the calcium source and adenosine 5′‐triphosphate disodium salt (ATP) as the phosphate source through the microwave‐assisted hydrothermal method. The effects of the concentration of CL, the microwave hydrothermal temperature, and the time on the morphology and crystal phase of the product are investigated. The possible formation mechanism of yolk‐shell porous microspheres of calcium phosphate is proposed. Hemoglobin from bovine red cells (Hb) and ibuprofen (IBU) are used to explore the application potential of yolk‐shell porous microspheres of calcium phosphate in protein/drug loading and delivery. The experimental results indicate that the as‐prepared yolk‐shell porous microspheres of calcium phosphate have relatively high protein/drug loading capacity, sustained protein/drug release, favorable pH‐responsive release behavior, and a high biocompatibility in the cytotoxicity test. Therefore, the yolk‐shell porous microspheres of calcium phosphate have promising applications in various biomedical fields such as protein/drug delivery.     

The High Energy X-ray telescope (HE) onboard the Insight-HXMT astronomy satellite

The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments.     

Facile preparation of boronic acid‐functionalized magnetic nanoparticles with a high capacity and their use in the enrichment of cis‐diol‐containing compounds from plasma

The use of bronate affinity adsorbents is a new separation method that appeared recently with great potential for specific extraction of cis‐diol‐containing compounds. In this work,a new strategy for the facile construction of boronic acid‐functionalized Fe₃O₄ magnetic nanoparticles (Fe₃O₄@FPBA MNPs) with a high capacity was described. The extraction capacity of the Fe₃O₄@FPBA MNPs was determined to be 66.0 ± 2.7 µmol/g for catechol and 80.6 ± 2.0 µmol/g for dopamine, being higher than that for the reported methods. The Fe₃O₄@FPBA MNPs were used to extract four cis‐diol drugs: caffeic acid isopropyl ester, caffic acid bornyl ester, isopropyl 3‐(3,4‐dihydroxyphenyl)‐2‐hydroxypropanoate and 3‐(3, 4‐dihydroxyphenyl)‐2‐hydroxylpropionic acid – from the spiked rabbit plasma, and the recoveries of four drugs were between 87.29 and104.37% with relative standard deviations ranging from 1.34 to 8.81%. Under the most favorable conditions, the solid‐phase extraction combined with HPLC‐UV for the analysis of four drugs in plasma could eliminate interferences from endogenous components of the biological fluids and exhibited sufficient precision and accuracy. These results showed that the prepared Fe₃O₄@FPBA MNPs were qualified for efficiently enriching and determining the trace cis‐diol substances from biological samples. Copyright © 2014 John Wiley & Sons, Ltd.     

From single‐chain folding to polymer nanoparticles via intramolecular quadruple hydrogen‐bonding interaction

Single‐chain folding via intramolecular noncovalent interaction is regarded as a facile mimicry of biomacromolecules. Single‐chain folding and intramolecular crosslinking is also an effective method to prepare polymer nanoparticles. In this study, poly(methyl methacrylate‐co?2‐ureido‐5‐deazapterines functionalized ethylene methacrylate) (P(MMA‐co‐EMA‐DeAP)) is synthesized via free radical polymerization. The single‐chain folding of P(MMA‐co‐EMA‐DeAP) and the formation of the nanoparticles in diluted solution (concentration <0.005 mg/mL) are achieved via supramolecular interaction and intramolecular collapsing during the disruption‐reformation process of the hydrogen bonding triggered by water. The size and the morphology of the nanoparticles are characterized by dynamic light scattering, transmission electron microscope, and atomic force microscope. The results show that the size of the nanoparticles depends on the molecular weight of the polymer and the loading of 2‐ureido‐5‐deazapterines functionalized ethylene methacrylate (EMA‐DeAP) on the polymer backbone. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1832–1840