Determination of a novel antifibrotic small molecule GDC‐3280 in human plasma and urine by liquid chromatography tandem mass spectrometry to support its first‐in‐human clinical trial

A specific and robust LC–MS/MS method was developed and validated for the quantitative determination of GDC‐3280 in human plasma and urine. The nonspecific binding associated with urine samples was overcome by the addition of CHAPS. The sample volume was 25 μL for either matrix, and supported liquid extraction was employed for analyte extraction. d6‐GDC‐3280 was used as the internal standard. Linear standard curves (R² > 0.9956) were established from 5.00 to 5000 ng/mL in both matrices with quantitation extended to 50,000 ng/mL through dilution. In plasma matrix, the precision (RSD) ranged from 1.5 to 9.9% (intra‐run) and from 2.4 to 7.2% (inter‐run); the accuracy (RE) ranged from 96.1 to 107% (intra‐run) and from 96.7 to 104% (inter‐run). Similarly, in urine the precision was 1.5–6.2% (intra‐run) and 1.9–6.1% (inter‐run); the accuracy was 83.1–99.3% (intra‐run) and 87.1–98.3% (inter‐run). Good recovery (>94%) and negligible matrix effect were achieved in both matrices. Long‐term matrix stability was established for at least 703 days in plasma and 477 days in urine. Bench‐top stability of 25 h and five freeze–thaw cycles were also confirmed in both matrices. The method was successfully implemented in GDC‐3280's first‐in‐human trial for assessing its pharmacokinetic profiles.     

Numerically stable,scalable formulas for parallel and online computation of higher-order multivariate central moments with arbitrary weights

Formulas for incremental or parallel computation of second order central moments have long been known, and recent extensions of these formulas to univariate and multivariate moments of arbitrary order have been developed. Such formulas are of key importance in scenarios where incremental results are required and in parallel and distributed systems where communication costs are high. We survey these recent results, and improve them with arbitrary-order, numerically stable one-pass formulas which we further extend with weighted and compound variants. We also develop a generalized correction factor for standard two-pass algorithms that enables the maintenance of accuracy over nearly the full representable range of the input, avoiding the need for extended-precision arithmetic. We then empirically examine algorithm correctness for pairwise update formulas up to order four as well as condition number and relative error bounds for eight different central moment formulas, each up to degree six, to address the trade-offs between numerical accuracy and speed of the various algorithms. Finally, we demonstrate the use of the most elaborate among the above mentioned formulas, with the utilization of the compound moments for a practical large-scale scientific application.     

Knowledge-Based Design of a Biosensor to Quantify Localized ERK Activation in Living Cells

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Speciation of Copper(II)-Betaine Complexes as Starting Point for Electrochemical Copper Deposition from Ionic Liquids

The application of ionic liquids for the dissolution of metal oxides is a promising field for the development of more energy- and resource-efficient metallurgical processes. Using such solutions for the production of valuable chemicals or electrochemical metal deposition requires a detailed understanding of the chemical system and the factors influencing it. In the present work, several compounds are reported that crystallize after the dissolution of copper(II) oxide in the ionic liquid [Hbet][NTf₂]. Dependent on the initial amount of chloride, the reaction temperature and the purity of the reagent, copper crystallizes in complexes with varying coordination geometries and ligands. Subsequently, the influence of these different complex species on electrochemical properties is shown. For the first time, copper is deposited from the ionic liquid [Hbet][NTf₂], giving promising opportunities for more resource-efficient copper plating. The copper coatings were analyzed by SEM and EDX measurements. Furthermore, a mechanism for the decomposition of [Hbet][NTf₂] in the presence of chloride is suggested and supported by experimental evidence.     

Avoiding Pitfalls in Comparison of Activity and Selectivity of Solid Catalysts for Electrochemical HMF Oxidation

Electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) offers a renewable approach to produce the value-added platform chemical 2,5-furandicarboxylic acid (FDCA). The key for the economic viability of this approach is to develop active and selective electrocatalysts. Nevertheless, a reliable catalyst evaluation protocol is still missing, leading to elusive conclusions on criteria for a high-performing catalyst. Herein, we demonstrate that besides the catalyst identity, secondary parameters such as materials of conductive substrates for the working electrode, concentration of the supporting electrolyte, and electrolyzer configurations have profound impact on the catalyst performance and thus need to be optimized before assessing the true activity of a catalyst. Moreover, we highlight the importance of those secondary parameters in suppressing side reactions, which has long been overlooked. The protocol is validated by evaluating the performance of free-standing Cu-foam, and CuCoO modified with NaPO₂H₂ and Ni, which were immobilized on boron-doped diamond (BDD) electrodes. Recommended practices and figure of merits in carefully evaluating the catalyst performance are proposed.     

Access to Optically Active 3‐Substituted Piperidines by Ring Expansion of Prolinols and Derivatives

The ring expansion of prolinols via an aziridinium intermediate gives C3‐substituted piperidines in good yields and enantiomeric excess, the substituent at the C3 position being derived from the most reactive nucleophile in the reaction mixture. Depending on the nucleophile, the reaction proceeds under thermodynamic or kinetic control. The regioselectivity of attack of nucleophiles on the aziridinium intermediate depends on the nature of the substituents on the nitrogen atom and the C4 position of the starting prolinols.     

Origin and Location of Electrons and Protons during the Formation of Intermetalloid Clusters [Sm@Ga3−xH3−2xBi10+x]3− (x=0, 1)

Reaction of [GaBi₃]^2? with [Sm(C₅Me₄H)₃] yielded the first protonated ternary intermetalloid clusters [Sm@Ga_3?xH_3?2xBi_10+x]^3? ( 1 ; x=0,1). The presence of the Ga? H bonds and the transfer of electrons and protons during the formation of 1 were elucidated by a combination of experimental and quantum chemical methods, thereby rationalizing the role of the solvent ethane‐1,2‐diamine as a Brønsted acid. As an organic by‐product, we observed the previously unknown octamethylfulvene ( 2 ) upon C? C coupling of (C₅Me₄H)^?.     

Asymmetric Transfer Hydrogenation of gem-Difluorocyclopropenyl Esters: Access to Enantioenriched gem-Difluorocyclopropanes

Catalytic enantioselective access to disubstituted functionalized gem-difluorocyclopropanes, which are emerging fluorinated motifs of interest in medicinal chemistry, was achieved through asymmetric transfer hydrogenation of gem-difluorocyclopropenyl esters, catalyzed by a Noyori–Ikariya (p-cymene)-ruthenium(II) complex, with (N-tosyl-1,2-diphenylethylenediamine) as the chiral ligand and isopropanol as the hydrogen donor. The resulting cis-gem-difluorocyclopropyl esters were obtained with moderate to high enantioselectivity (ee=66–99 %), and post-functionalization reactions enable access to valuable building blocks incorporating a cis- or trans-gem-difluorocyclopropyl motif.