Liquid chromatography tandem mass spectrometry method for determination of fulvestrant in rat plasma and its application to pharmacokinetic studies of a novel fulvestrant microcrystal

Fulvestrant (‘Faslodex’), an estrogen receptor antagonist, is available for the treatment of advanced breast cancer. The oil-based vehicle of Faslodex can lead to various adverse effects. A novel fulvestrant microcrystal (aqueous suspension) was developed in this study to eliminate these adverse effects. A sensitive and robust liquid chromatography tandem mass spectrometry method was developed and validated for the determination of fulvestrant in rat plasma using supported-liquid extraction. The separation of fulvestrant was achieved on an Agilent SB-C₁₈ column (2.1 × 50 mm, 3.5 μm) with isocratic elution using fulvestrant-d3 as internal standard. Mass spectrometric detection was conducted in negative multiple reaction monitoring mode. Ion transitions were at m/z 605.5 → 427.5 for fulvestrant and m/z 608.5 → 430.5 for fulvestrant-d3. The excellent linearity was demonstrated over the range 0.05–100.0 ng/ml (r² = 0.99). The lower limit of quantitation was 0.05 ng/ml, which was superior to that reported in literature The method validation was evaluated by selectivity, accuracy, precision, recovery and matrix effect in agreement with the US Food and Drug Administration guidance. The method was successfully applied to a pharmacokinetic study of a novel fulvestrant microcrystal in rats after intramuscular administration. It revealed that the rate of absorption increases and the extent of absorption is constant with a decrease in microcrystal diameter.     

Thermal performances of saturated porous soil during freezing process using lattice Boltzmann method

Journal of Thermal Analysis and Calorimetry - A stochastic growth method for generating the porous soil structure is proposed, and an enthalpy-based lattice Boltzmann phase transition model is...     

WEIGHTED INEQUALITIES FOR THE GEOMETRIC MAXIMAL OPERATOR ON MARTINGALE SPACES

In this article, the authors introduce two operators-geometrical maximal operator Mo and the closely related limiting operator M0^＊, then they give sufficient conditions under which the equality M0=MM0^＊ holds, and characterize the equivalent relations between the weak or strong type weighted inequality and the property of W∞-weight or W∞^＊-weight for the geometrical maximal operator in the case of two-weight condition. What should be mentioned is that the new operator-the geometrical minimal operator is equal to the limitation of the minimal operator sequence, and the results for the minimal operator proved in [12] makes the proof elegant and evident.     

Electrocatalytic activity of supported gold nanoparticles toward CO oxidation: The perimeter effect of gold–support interface

The gold nanoparticles (AuNPs) sputtered on indium tin oxide (ITO) were used to investigate the origin of the high catalytic activity of AuNPs toward electrooxidation of CO in alkali media. We demonstrated that the catalytic activity is closely related to the gold–ITO perimeter, which represents only a very small percentage of the total surface area of AuNPs. Increasing the perimeter-to-surface ratio of the ITO-supported AuNPs leads to an increase of catalytic activity. This work provides a potential strategy to further promote the catalytic activity of AuNPs in the electrochemical system.     

Three New Dimeric Orcinol Glucosides from Curculigo orchioides

Three new phenolic glucosides named orcinosides A, B, and C ( 1, 2 , and 3 , resp.) were isolated in low yields (4.0×10⁻⁶, 11.5×10⁻⁶, 4.5×10⁻⁶%, resp.) from the rhizomes of Curculigo orchioides. Their structures were elucidated by comprehensive spectroscopic analyses including FAB‐MS, HR‐ESI‐MS, IR, and 1D‐ and 2D‐NMR (HSQC, HMBC) data. Compounds 1 – 3 contained two orcinol‐glucoside moieties linked through a CH₂ group.     

Higher order accuracy analysis of the second-order normal form method

The second-order normal form method has shown its intelligence in handling the weak nonlinear vibration problems, especially the lightly damped nonlinearities. The new technology can directly realize near identify transformation to the differential equation, while the first-order method has to change the differential equation to the first-order form at the very beginning. In order to get a more precise result, a lot of effort has been done to realize it through eliminating unnecessary approximations or reconsidering the influence of the nonlinearity in the subsequent processing. It is easy to conduct a simplified nonlinear transformation to get the first-order motion equation. Here in this paper, we focus on the higher-order accurate terms in the dynamic equation. The Taylor series expansion and the Poincaré expansion of the nonlinearity indicate that there are other resonance terms existing in final dynamic equation. A?general form of expression for higher-order resonance response function has been derived. The results show that the additional resonance terms cannot obviously increase the accuracy of the second-order normal form method; also, it cannot improve much of the predictions of sub and superharmonic responses.     

On the Generalized Cartan Matrices Arising from k-th Yau Algebras of Isolated Hypersurface Singularities

Algebras and Representation Theory - Let (V,0) be an isolated hypersurface singularity defined by the holomorphic function $f: (\mathbb {C}^{n}, 0)\rightarrow (\mathbb {C}, 0)$ . The k-th Yau...