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High-performance liquid chromatography evaluation of lipophilicity and QSRR modeling of a series of dual DNA gyrase and topoisomerase IV inhibitors

Dobričić Vladimir, Savić Jelena, Tomašič Tihomir, Durcik Martina, Zidar Nace, Peterlin Mašič Lucija, Ilaš Janez, Kikelj Danijel, Čudina Olivera

Acta Chromatographica

2024

Vol. 36, no. 1

45--51

Bacterial DNA gyrase and topoisomerase IV control the topological state of DNA during replication and represent important antibacterial drug targets. To be successful as drug candidates, newly synthesized compounds must possess optimal lipophilicity, which enables efficient delivery to the site of action. In this study, retention behavior of twenty-three previously synthesized dual DNA gyrase and topoisomerase IV inhibitors was tested in RP-HPLC system, consisting of C8 column and acetonitrile/phosphate buffer (pH 5.5 and pH 7.4) mobile phase. logD was calculated at both pH values and the best correlation with logD was obtained for retention parameter ϕ0, indicating that this RP-HPLC system could be used as an alternative to the shake-flask determination of lipophilicity. Subsequent QSRR analysis revealed that intrinsic lipophilicity (logP) and molecular weight (bcutm13) have a positive, while solubility (bcutp3) has a negative influence on this retention parameter.

A new simple liquid chromatographic assay for gentamicin in presence of methylparaben and propylparaben

Ivković Branka, Milutinović Ivana, Čudina Olivera, Marković Bojan

Acta Chromatographica

2023

Vol. 35, no. 1

81--87

Gentamicin sulfate is a potent broad spectrum aminoglycoside antibiotic which is used against Gram-positive and Gram-negative bacteria. A simple, isocratic HPLC method for separation, identification and determination of gentamicin and parabens (methylparaben and propylparaben) was developed and validated. To our knowledge there is no report about simultaneous determination of those three analytes in pharmaceutical products. The optimum chromatographic conditions were achieved on CN column with a mobile phase consisting of 0.15% triethylamine in 10 mM KH₂PO₄ aqueous solution (final pH 3.0 adjusted with H₃PO₄) and methanol in the ratio 70:30 (v/v), providing selective quantification of analytes within 5 min. The method was successfully validated according to ICH guidelines acceptance criteria in terms of selectivity, linearity, accuracy, precision and robustness. The linearity of the method was proved in defined concentrations ranges for gentamicin (0.32–1.04 mg mL⁻¹), methylparaben (0.0072–0.0234 mg mL⁻¹) and propylparaben (0.0008–0.0026 mg mL⁻¹). Relative standard deviations calculated for all analytes in precision testing were <2% (analysis repeatability) and <3% (intermediate precision). Recovery values were between 98.87% and 101.67%. Chromatographic parameters are not significantly influenced by small variations of column temperature, pH and molarity of KH₂PO₄. Finally, the method was successfully applied for quantitative determination of gentamicin and parabens in commercially available solution for injection. Proposed HPLC method is found to be promising in terms of simplicity, analysis times and non-use of derivatization and ion-pair agents.

Estimation of lipophilicity and design of new 17β-carboxamide glucocorticoids using RP-HPLC and quantitative structure-retention relationships analysis

Dobričić Vladimir, Bošković Jelena, Vukadinović Dragana, Vladimirov Sote, Čudina Olivera

Acta Chromatographica

2022

Vol. 34, no. 2

130--137

Eight 17β-carboxamide glucocorticoids with local anti-inflammatory activity were selected and their retention behavior tested in six RP-HPLC systems (I–VI). logkw, a, and φ 0 parameters were calculated and correlation with previously determined logPo/w values was examined. RP-HPLC system IV, which consisted of cyano column and methanol–water mobile phases (50:50, 60:40, 70:30, and 80:20, v/v), was selected as the most reliable for lipophilicity prediction and used for the analysis of chromatographic behavior of remaining fourteen 17β-carboxamide glucocorticoids. Quantitative structure-retention relationships analysis was performed and PLS(logkw) model was selected as the most statistically significant. On the basis of selected model and interpretation of corresponding descriptors, new derivatives with higher logkw values and higher expected lipophilicity were designed.