Conformational flexibility of mephenesin.

The mephenesin molecule (3-(2-methylphenoxy)propane-1,2-diol) serves as a test bank to explore several structural and dynamical issues, such as conformational flexibility, the orientation of the carbon linear chain relative to the benzene plane, or the effect of substituent position on the rotational barrier of a methyl group. The molecule has been studied by rotational spectroscopy in the 4-18 GHz frequency range by Fourier-transform methods in a supersonic expansion. The experiment has been backed by a previous conformational search plus optimization of the lowest energy structures by ab initio and density functional quantum calculations. The three lowest-lying conformers that can interconvert to each other by simple bond rotations have been detected in the jet. Rotational parameters for all structures have been obtained, and methyl torsional barriers have been determined for the two lowest-lying rotamers. The lowest-lying structure of mephenesin is highly planar, with all carbon atoms lying nearly in the benzene ring plane, and is stabilized by the formation of cooperative intramolecular hydrogen bonding. An estimation of the relative abundance of the detected conformers indicates that the energetically most stable conformer will have an abundance near 80% at temperatures relevant for biological activity.

Validación de un método cromatográfico para la cuantificación de mefenesina en tabletas de producción nacional / A chromatographic method validation to quantify tablets Mephenesine of national production

Se realizó la validación de un método analítico por cromatografía líquida de alta eficiencia para la cuantificación de mefenesina en tabletas de 500 mg reformuladas recientemente. Con respecto a su aplicación al control de calidad, la validación incluyó los parßmetros linealidad, exactitud, precisión y selectividad. Los resultados fueron satisfactorios en el rango de 50-150 por ciento. Para su empleo en estudios posteriores de estabilidad química, se evaluó adicionalmente la selectividad para estabilidad y la sensibilidad. Los límites de detección y cuantificación estimados resultaron adecuados y el método fue selectivo frente a los posibles productos de degradación.

Authors made validation of an analytical method by high performance liquid chromatography (HPLC) for quantification of Mephenesine in recently reformulated 500 mg tablets. With regard to its application to quality control, validation included the following parameters: linearity, accuracy, precision, and selectivity. Results were satisfactory within 50-150 percent rank. In the case of its use in subsequent studies of chemical stability, the selectivity for stability and sensitivity was assessed. Estimated detection and quantification limits were appropriate, and the method was selective versus the possible degradation products.

Validación de un método cromatográfico para la cuantificación de mefenesina en tabletas de producción nacional / A chromatographic method validation to quantify tablets Mephenesine of national production

Se realizó la validación de un método analítico por cromatografía líquida de alta eficiencia para la cuantificación de mefenesina en tabletas de 500 mg reformuladas recientemente. Con respecto a su aplicación al control de calidad, la validación incluyó los parßmetros linealidad, exactitud, precisión y selectividad. Los resultados fueron satisfactorios en el rango de 50-150 por ciento. Para su empleo en estudios posteriores de estabilidad química, se evaluó adicionalmente la selectividad para estabilidad y la sensibilidad. Los límites de detección y cuantificación estimados resultaron adecuados y el método fue selectivo frente a los posibles productos de degradación(AU)

Authors made validation of an analytical method by high performance liquid chromatography (HPLC) for quantification of Mephenesine in recently reformulated 500 mg tablets. With regard to its application to quality control, validation included the following parameters: linearity, accuracy, precision, and selectivity. Results were satisfactory within 50-150 percent rank. In the case of its use in subsequent studies of chemical stability, the selectivity for stability and sensitivity was assessed. Estimated detection and quantification limits were appropriate, and the method was selective versus the possible degradation products(AU)

The synthesis of amphipathic prodrugs of 1,2-diol drugs with saccharide conjugates by high regioselective enzymatic protocol.

A facile, high regioselective enzymatic synthesis approach for the preparation of amphipathic prodrugs with saccharides of mephenesin and chlorphenesin was developed. Firstly, transesterification of two drugs with divinyl dicarboxylates with different carbon chain length was performed under the catalysis of Candida antarctica lipase acrylic resin and Lipozyme in anhydrous acetone at 50 degrees C, respectively. A series of lipophilic derivatives with vinyl groups of mephenesin and chlorphenesin were prepared. The influences of different organic solvents, enzyme sources, reaction time, and the acylation reagents on the synthesis of vinyl esters were investigated. And then, protease-catalyzed high regioselective acylation of D-glucose and D-mannose with vinyl esters of mephenesin and chlorphenesin gave drug-saccharide derivatives in good yields. The studies of lipophilicity and hydrolysis in vitro of prodrugs verified that drug-saccharide derivatives had amphipathic properties, and both lipophilic and amphipathic drug derivatives had obvious controlled release characteristics.