Preparation and application of teicoplanin functionalized polymeric monolith for enantioseparation of chiral drugs.

A novel chiral stationary phase (CSP), based on a monolithic organic polymer chemically modified with teicoplanin, was fabricated within a 100 µm I.D. fused silica capillary. The teicoplanin was firstly derivatized with 2-isocyanatoethyl methacrylate (ICNEML) and then thermally co-polymerized with the crosslinker ethylene dimethacrylate (EDMA) in presence of porogens (methanol and dimethylsulfoxide). The optimal experimental conditions (e.g., concentration and ratio of the reagents), considering enantioresolution and permeability, were systematically investigated. The prepared monolith was evaluated using scanning electron microscopy, and the column exhibited quite good morphology. In order to further evaluate the enantioresolving power of the poly(ICNEML-teicoplanin-co-EDMA) monolith, a series of basic and acidic chiral compounds were analyzed using an isocratic mode of polar organic solvents (methanol and acetonitrile) or the same solvents in combination with water (reversed-phase) by nano-liquid chromatography. Five mandelic acids and six derivatized amino acids were enantioresolved under reversed-phase mode (Rs = 1.22-3.47 and α = 1.43-6.33). This monolithic teicoplanin-CSP was also effective in the enantioseparations of 17 amino alcohol drugs employing polar-organic phase mode (MeOH/ACN/TEA/HOAc (80/20/0.03/0.055, v/v/v/v)). Ten of them were baseline enantioresolved (alprenolol, betaxolol, clenbuterol, isoproterenol, metoprolol, pindolol, propranolol, salbutamol, sotalol, tertatolol) (Rs = 1.55-2.48 and α = 1.21-1.55), while the others were partially enantioseparated (Rs = 1.14-1.48).

A facile and efficient single-step approach for the fabrication of vancomycin functionalized polymer-based monolith as chiral stationary phase for nano-liquid chromatography.

A facile single-step preparation strategy for fabricating vancomycin functionalized organic polymer-based monolith within 100µm fused-silica capillary was developed. The synthetic chiral functional monomer, i.e 2-isocyanatoethyl methacrylate (ICNEML) derivative of vancomycin, was co-polymerized with the cross-linker ethylene dimethacrylate (EDMA) in the presence of methanol and dimethyl sulfoxide as the selected porogens. The co-polymerization conditions were systematically optimized in order to obtain satisfactory column performance. Adequate permeability, stability and column morphology were observed for the optimized poly(ICNEML-vancomycin-co-EDMA) monolith. A series of chiral drugs were evaluated on the monolith in either polar organic-phase or reversed-phase modes. After the optimization of separation conditions, baseline or partial enantioseparation were obtained for series of drugs including thalidomide, colchicine, carteolol, salbutamol, clenbuterol and several other ß-blockers. The proposed single-step approach not only resulted in a vancomycin functionalized organic polymer-based monolith with acceptable performance, but also significantly simplified the preparation procedure by reducing time and labor.

Thymic stromal lymphopoietin is expressed in human corneal stromal cells and secreted upon protease-activated receptor 1 activation.

Thymic stromal lymphopoietin (TSLP) is an interleukin-7 (IL-7) like cytokine that triggers inflammatory responses through activating dendritic cell. It is demonstrated to be involved in a number of disorders, including cancer, gastrointestinal diseases, and autoimmune diseases. In addition, TSLP is also found to be able to induce itch sensation by directly activating the itch sensory neurons. The expression of human TSLP is detected in various tissues such as heart, liver, testis, and prostate. In this study, we report that TSLP was expressed in the human corneal stromal cells, the highly specialized cells that are critical for the function of the cornea. Furthermore, we found that activation of the protease-activated receptor 1 (PAR1) induced secretion of TSLP by the corneal stromal cells. Beside the canonical activator thrombin, PAR1 can also be activated by a few matrix metalloproteases (MMPs) such as MMP1 and MMP13. Since MMPs including MMP1 and MMP13 are upregulated in many corneal diseases as well as the corneal wound healing process, we proposed that TSLP might function as the link between increased protease activity and inflammatory responses or itch sensation in the corneas. © 2017 IUBMB Life, 69(8):606-610, 2017.