The aim of present study was to prepare and evaluate mouth dissolving tablets of ibuprofen (IBU). Ternary solid dispersion (SD) of IBU was prepared using PEG 4000 as carrier and Tween 80 as surfactant. The SD formulations were prepared by solvent evaporation and melt solvent method by varying ratio of PEG 4000. Different weight ratio of carrier, drug and surfactant 5 : 5 : 1, 10 : 5 : 1, 25 : 5 : 1, 35 : 5 : 1 and 45 : 5 : 1 was taken. The prepared SD formulations were characterized by Fourier Transform Infra-Red (FT-IR) spectroscopy, differential scanning calorimetry (DSC), X-ray diffraction (XRD) and in vitro drug release. Mouth dissolving tablets of IBU were formulated using optimized SD formulation of carrier : drug : surfactant ratio, 10 : 5 : 1 along with superdisintegrants. The best developed formulation was compared with marketed tablet product of IBU. From IR and XRD studies, it may be concluded that there is change in crystalline form of drug into amorphous during formation of SD. From DSC studies, it was predicted that drug was completely dissolved in the carrier. Mouth dissolving tablets containing Ac-Di-Sol (12%) as super-disintegrant showed the fastest disintegration (202s) and in vitro drug release (84.57%). The release pattern of all developed formulations followed Peppas-Korsmeyer model as the plot between log cumulative % drug released versus log time showed good linearity (rϾ0.99) with a comparatively high slope (n) value within the range of 0.44-0.67. The tablets containing SD exhibited better dissolution profile than commercial tablets.
The role of chiral metal catalysts in asymmetric reactions has developed a new forte for researchers worldwide to boost chiral synthesis in various sectors. By controlling specific interactions among chiral ligands, metal catalysts and the support material, one can design a more selective and efficient chiral heterogeneous catalytic system. Silica has been extensively used as support material in various heterogeneous systems due to its activity, stability, better recovery, and recyclability. This review details recent advances in preparation of the silica suppported chiral catalysts and their applications for various chiral transformatios such as Aldol reaction, Henry reaction, transfer hydrogenation, epoxidation, Passerini reaction etc. The review also covers different mechanisms of immobilization viz., adsorption, electrostatic and covalent interactions. The interaction mechanism of chiral metal catalyst with silica support and factors like matrix pore size and ligand confinement that influence the catalytic performance of enantioselective transformations have also been discussed.
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