A rapid UPLC‐MS/MS method for the determination of oleanolic acid in rat plasma and liver tissue: application to plasma and liver pharmacokinetics

A reliable high‐throughput ultra‐high performance liquid chromatography–tandem mass spectrometry (UPLC‐MS/MS) method was developed and validated for oleanolic acid (OA) determination in rat plasma and liver tissue using glycyrrhetic acid as the internal standard (IS). Plasma and liver homogenate samples were prepared using solid‐phase extraction. Chromatographic separation was achieved on a C₁₈ column using an isocratic mobile phase system. The detection was performed by multiple reaction monitoring mode via positive electrospray ionization interface. The calibration curves showed good linearity (R² > 0.9997) within the tested concentration ranges. The lower limit of quantification for plasma and liver tissue was ≤0.75 ng/mL. The intra‐ and inter‐day precision and accuracy deviations were within ±15% in plasma and liver tissue. The mean extraction recoveries ranged from 80.8 to 87.0%. In addition, the carryover, matrix effect, stability and robustness involved in the method were also validated. The method was successfully applied to the plasma and hepatic pharmacokinetics of OA after oral administration to rats. Copyright © 2015 John Wiley & Sons, Ltd.     

Sulfonylation from sodium dithionite or thiourea dioxide

The cheap and easily available sodium dithionite and thiourea dioxide have been used as the source of sulfonyl group in the synthesis of sulfones and sulfonamides recently.Compared with other methods for the sulfonylation reactions,the strategies using sodium dithionite or thiourea dioxide provide an alternative and complementary route to diverse sulfonyl compounds.During the reaction process,sulfur dioxide anion radical is the key intermediate,which is usually generated from a single electron transfer under suitable conditions.The advantages using sodium dithionite or thiourea dioxide in the sulfonylation reactions include mild conditions and broad substrate scope with excellent functional group compatibility.Further applications by using sodium dithionite and thiourea dioxide in organic transformations will be anticipated.     

Efficient conversion of fructose to 5-hydroxymethylfurfural over sulfated porous carbon catalyst

Sulfated porous carbon (PC-SO3H) catalyst was successfully synthesized from one-pot treatment of porous polydivinylbenzene in H2SO4 at 250 C, which exhibited very good catalytic performances in the production of 5-hydroxymethylfurfural from fructose.     

Ultrasound-assisted Extraction of Kamebakaurin from Rabdosia excisa by Response Surface Methodology

For the efficient extraction of kamebakaurin（KA）, the ultrasound-assisted extraction（UAE） of KA from Rabdosia excisa（R, excisa） via response surface methodology（RSM） was investigated with high-performance liquid chromatography（HPLC）. Effects of the experimental parameters such as extraction solvent, ratio of liquid to plant material, extraction time and extraction temperature on the extracting efficiency of KA from R. excisa were evaluated, and the purity of KA in residual was calculated. The optimized conditions were 65.5%（volume fraction） acetone, 35 ℃, time of 24.6 min with ultrasound of 80 W/L, 40 kHz, ratio of liquid to plant material at 30：1（mL/g）. The maximum yield of KA is 0.708 mg/kg, with mean purity of 6.09%, indicating that ultrasound-assisted extraction is a feasible and useful method for extracting KA from R. excisa.     

Synthesis and characterization of intrinsic high‐barrier polyimide derived from a novel diamine monomer containing rigid planar moiety

A new diamine monomer containing rigid planar fluorenone moiety, 2,7‐bis(4‐aminophenyl)‐9H‐fluoren‐9‐one, was synthesized through Suzuki coupling reaction. Then it was reacted with pyromellitic dianhydride to obtain a polyimide (FOPPI) via a conventional two‐step polymerization process. The prepared FOPPI exhibits excellent barrier properties, with the oxygen transmission rate and water vapor transmission rate low to 3.2 cm³·m^?2·day^?1 and 2.9 g·m^?2·day^?1, respectively. The results of wide angle X‐ray diffractograms, positron annihilation lifetime spectroscopy, and molecular dynamics simulations reveal that the excellent barrier properties of FOPPI are mainly ascribed to the crystallinity, high chain rigidity, and low free volume, which are resulted from the rigid planar moiety. FOPPI also shows outstanding thermal stability and mechanical properties with a glass transition temperature up to 420 °C, 5% loss temperature of 607 °C, coefficient of thermal expansion of 1.28 ppm K^?1, and tensile strength of 150.8 MPa. The polyimide has an attractive potential application prospect in the flexible electronics encapsulation area. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2373–2382     

Effects of additives and post‐treatment on the thermoelectric performance of vapor‐phase polymerized PEDOT films

Vapor‐phase polymerization (VPP) is an important method for the fabrication of high‐quality conducting polymers, especially poly(3,4‐ethylenedioxythiophene) (PEDOT). In this work, the effects of additives and post‐treatment solvents on the thermoelectric (TE) performance of VPP‐PEDOT films were systematically investigated. The use of 1‐butyl‐3‐menthylinidazolium tetrafluoroborate ([BMIm][BF₄], an ionic liquid) was shown to significantly enhance the electrical conductivity of VPP‐PEDOT films compared with other additives. The VPP‐PEDOT film post‐treated with mixed ethylene glycol (EG)/[BMIm][BF₄] solvent displayed the high power factor of 45.3 μW m^?1 K^?2 which is 122% higher than that prepared without any additive or post‐treatment solvent, along with enhanced electrical conductivity and Seebeck coefficient. This work highlighted the superior effect of the [BMIm][BF₄] additive and the EG/[BMIm][BF₄] solvent post‐treatment on the TE performance of the VPP‐PEDOT film. These results should help with developing the VPP method to fabricate high‐performance PEDOT films. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 1738–1744     

Molecular-scale drug delivery systems loaded with oxaliplatin for supramolecular chemotherapy

Smart strategies that can decrease the side effect and enhance the therapeutic efficacy of chemotherapy are in urgent need to meet the special demands of cance r therapy.Herein,two wate r-soluble macrocyclic hosts,i.e.,a carboxylated leaning tower[6]arene(CLT6) and a carboxylated [2]biphenyl-extended pillar[6]arene(CBpP6),are used to load chemotherapy drug oxaliplatin(OxPt) by forming inclusion complexes(OxPt■CLT6 and OxPt■CBpP6) through host-guest interactions.Interestingly,OxPt can be released from the macrocyclic cavities of these drug delivery systems(DDSs) via the competitive binding effect of spermine(SPM) because of the stronger binding abilities of CLT6/CBpP6 toward SPM as compared with OxPt,leading to enhanced cytotoxicity on SPM-overexpressed cancer cells,such as breast cancer MCF-7 cells.Moreover,compared to free OxPt,due to the low concentration of SPM in normal cells,OxPt■CGT6 and OxPt■CBpP6 demonstrated a decreased cytotoxicity on liver L02 cells,which is beneficial fo r reducing the side effect of anticancer drug during chemotherapy.Such a strategy might be extended to other antitumor drugs and water-soluble macrocycles with suitable cavity sizes to achieve controllable drug delivery and enhanced anticancer ability in supramolecular chemotherapy