- Nanocellulose derivative/silica hybrid core-shell chiral stationary phase: Preparation and enantioseparation performance
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Core-shell silica microspheres with a nanocellulose derivative in the hybrid shell were successfully prepared as a chiral stationary phase by a layer-by-layer self-assembly method. The hybrid shell assembled on the silica core was formed using a surfactant as template by the copolymerization reaction of tetraethyl orthosilicate and the nanocellulose derivative bearing triethoxysilyl and 3,5-dimethylphenyl groups. The resulting nanocellulose hybrid core-shell chiral packing materials (CPMs) were characterized and packed into columns, and their enantioseparation performance was evaluated by high performance liquid chromatography. The results showed that CPMs exhibited uniform surface morphology and core-shell structures. Various types of chiral compounds were efficiently separated under normal and reversed phase mode. Moreover, chloroform and tetrahydrofuran as mobile phase additives could obviously improve the resolution during the chiral separation processes. CPMs still have good chiral separation property when eluted with solvent systems with a high content of tetrahydrofuran and chloroform, which proved the high solvent resistance of this new material.
- Zhang, Xiaoli,Wang, Litao,Dong, Shuqing,Zhang, Xia,Wu, Qi,Zhao, Liang,Shi, Yanping
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- In silico approach towards lipase mediated chemoenzymatic synthesis of (S)-ranolazine, as an anti-anginal drug
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An in silico modelling based biocatalytic approach for the synthesis of drugs and drug intermediates in enantiopure forms is a rationalized methodology over the organo-chemical routes. In this study, enzyme-ligand based docking was carried out using (RS)-ranolazine, as the model drug for the screening of a suitable biocatalyst for the kinetic resolution of the racemic drug. The differential interaction of the two enantiomers with the lipase was analyzed on the basis of docking score and H-bond interaction with the amino acid residues, which helped to define the trans-esterification mechanism. Ranolazine [N-(2,6-dimethylphenyl)-2-[4-(2-hydroxy)-3-(2-methoxyphenoxy)propylpiperazin-1-yl]acetamide], an anti-anginal drug, significantly reduces the frequency of anginal attack and has also been used for the treatment of ventricular arrhythmias, and bradycardia. Various lipases were examined via computational as well as wet lab screening and Candida antartica lipase in the form of CLEA was the most efficient one for the (S)-selective kinetic resolution of (RS)-ranolazine, with highest conversion and enantiomeric excess. This is the first report of the chemo-enzymatic synthesis of (S)-ranolazine where the whole drug molecule was used for lipase catalysis. The present study showed that the combination of in silico studies and a classical wet lab approach could change the paradigm of biocatalysis.
- Sawant, Ganesh,Ghosh, Saptarshi,Banesh, Sooram,Bhaumik, Jayeeta,Chand Banerjee, Uttam
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p. 49150 - 49157
(2016/06/09)
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