A novel stability indicating LC method was developed and validated for the quantitative determina... more A novel stability indicating LC method was developed and validated for the quantitative determination of riluzole in bulk drugs and in pharmaceutical dosage forms in the presence of its isomers, related substances and degradation products. The drug was subjected to stress conditions of hydrolysis (acid, base and neutral), oxidation, photolysis and thermal degradation. Considerable degradation was observed under base hydrolysis and oxidation. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.5%. The developed method was validated with respect to linearity, accuracy, precision, specificity, ruggedness and robustness.
Journal of Liquid Chromatography & Related Technologies, 2012
A simple, sensitive, and reproducible ultra-performance liquid chromatography (UPLC) coupled with... more A simple, sensitive, and reproducible ultra-performance liquid chromatography (UPLC) coupled with a photodiode array detector method was developed for the quantitative determination of olmesartan medoxomil (OLM) in active pharmaceutical ingredient (API) and pharmaceutical dosage forms. Chromatographic separation was achieved on Acquity UPLC BEH phenyl 100 mm, 2.1 mm, and 1.7 µm phenyl columns and the gradient eluted within a short run time, that is, within 10.0 min. The eluted compounds were monitored at 210 nm, the flow rate was 0.3 mL/min and the column oven temperature was maintained at 27°C. The resolution of OLM and seventeen (potential, bi-products, and degradation products) impurities was greater than 2.0 for all pairs of components. The high correlation coefficient (R2 > 0.9991) values indicated clear correlations between the investigated compound concentrations and their peak areas within the LOQ (limit of quantification) to 150% level. The drug was subjected to the International Conference on Harmonization (ICH)-prescribed hydrolytic, oxidative, photolytic, and thermal stress conditions. The performance of the method was validated according to the present ICH guide lines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, ruggedness, and robustness.
The proton ligand constants of 4-chloro and 4-amino picolinic acid N-oxide and the formation cons... more The proton ligand constants of 4-chloro and 4-amino picolinic acid N-oxide and the formation constants of corresponding binary chelates of Cu(II) and Ni(II) have been measured at 30°C and 0.1M ionic strength in varying percentages of dioxane-water, acetone-water, ethanol-water and isopropanol-water. The results are discussed with reference to the change in dielectric constants of water in the presence of organic solvent, change in the structuredness of water, change in hydrogen bonding ability of the organic solvent in water, solvent basicity and proton solvation by organic solvent. The values have been compared with aqueous and mixed aqueous systems of picolinic acid N-oxide and 4-methoxy picolinic acid N-oxide.
A novel stability indicating LC method was developed and validated for the quantitative determina... more A novel stability indicating LC method was developed and validated for the quantitative determination of riluzole in bulk drugs and in pharmaceutical dosage forms in the presence of its isomers, related substances and degradation products. The drug was subjected to stress conditions of hydrolysis (acid, base and neutral), oxidation, photolysis and thermal degradation. Considerable degradation was observed under base hydrolysis and oxidation. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.5%. The developed method was validated with respect to linearity, accuracy, precision, specificity, ruggedness and robustness.
Journal of Liquid Chromatography & Related Technologies, 2012
A simple, sensitive, and reproducible ultra-performance liquid chromatography (UPLC) coupled with... more A simple, sensitive, and reproducible ultra-performance liquid chromatography (UPLC) coupled with a photodiode array detector method was developed for the quantitative determination of olmesartan medoxomil (OLM) in active pharmaceutical ingredient (API) and pharmaceutical dosage forms. Chromatographic separation was achieved on Acquity UPLC BEH phenyl 100 mm, 2.1 mm, and 1.7 µm phenyl columns and the gradient eluted within a short run time, that is, within 10.0 min. The eluted compounds were monitored at 210 nm, the flow rate was 0.3 mL/min and the column oven temperature was maintained at 27°C. The resolution of OLM and seventeen (potential, bi-products, and degradation products) impurities was greater than 2.0 for all pairs of components. The high correlation coefficient (R2 > 0.9991) values indicated clear correlations between the investigated compound concentrations and their peak areas within the LOQ (limit of quantification) to 150% level. The drug was subjected to the International Conference on Harmonization (ICH)-prescribed hydrolytic, oxidative, photolytic, and thermal stress conditions. The performance of the method was validated according to the present ICH guide lines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, ruggedness, and robustness.
The proton ligand constants of 4-chloro and 4-amino picolinic acid N-oxide and the formation cons... more The proton ligand constants of 4-chloro and 4-amino picolinic acid N-oxide and the formation constants of corresponding binary chelates of Cu(II) and Ni(II) have been measured at 30°C and 0.1M ionic strength in varying percentages of dioxane-water, acetone-water, ethanol-water and isopropanol-water. The results are discussed with reference to the change in dielectric constants of water in the presence of organic solvent, change in the structuredness of water, change in hydrogen bonding ability of the organic solvent in water, solvent basicity and proton solvation by organic solvent. The values have been compared with aqueous and mixed aqueous systems of picolinic acid N-oxide and 4-methoxy picolinic acid N-oxide.
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