Lusupultide

Cyclodextrin-based stationary phases are important chiral selectors in liquid chromatography. These chiral selectors are most commonly used in the reversed-phase mode because native cyclodextrin assumes a torus conformation with a hydrophobic cavity, facilitating inclusion complexation in aqueous environments. However, the value of native and aliphatic-derivatized cyclodextrins in other modes, such as the normal phase liquid chromatography (NPLC) or super/subcritical fluid chromatography (SFC), remains unexplored. In this work, we report chiral separations of pharmaceutically relevant compounds with the 1,4-dihydropyridine (DHP) scaffold on a 2-hydroxypropyl-β-cyclodextrin (CD-RSP) stationary phase in NPLC and SFC modes. Although CD-RSP is conventionally considered only effective in the reversed-phase mode, we show that these compounds tend to separate better in other modes. This is particularly apparent for analytes with hydrogen-bonding moieties. We propose that the separation mechanism primarily depends on external adsorption rather than inclusion complexation. The negligible impact of a complexation-competitive additive on retention in non-aqueous modes further supports this claim. Additionally, van Deemter analysis demonstrated the efficiency and environmental benefit of using this stationary phase in the SFC mode, further highlighting the promise of aliphatic derivatized cyclodextrin stationary phases for greener separations.

Recombinant spider silk protein (RSP) is a promising biomaterial for developing high-performance materials independent of fossil fuels. In this study, we investigated the influence of the initial secondary structure of RSPs on the properties of RSP-based hydrogels. By altering the initial structure of RSP to β-sheets (β-RSP), α-helices (α-RSP), and random coils (rc-RSP) through solvent treatment, we compared the structures and mechanical properties of the resulting gels. Solid-state NMR revealed a β-sheet-rich structure in all gels, with the α-RSP gel exhibiting significantly higher strength and Young's modulus compared to the rc-RSP gel. X-ray diffraction revealed that the α-RSP gel had a unique crystalline structure, distinguishing it from the β-RSP and rc-RSP gels. The different initial secondary structures possibly lead to variations in the crystalline and network structures of the molecular chains within the gels, explaining the superior mechanical properties observed in the α-RSP gels.