Authors:A. Malenovic, B. Jancic-Stojanovic, M. Medenica, and D. Ivanovic
This paper reports development and validation of a new microemulsion liquid chromatographic (MELC) method for rapid screening of simvastatin and simvastatin acid in human plasma. Plasma samples were injected directly into the HPLC system after appropriate sample dilution with mobile phase. Separations were performed on a 4.6 mm × 150 mm, 5-μm particle, C18 column, with UV detection at 238 nm. The mobile phase was 0.5% (w/υ) diisopropyl ether, 1.0% (w/υ) sodium dodecylsulphate (SDS), 4.0% (w/v) n-butanol, and 94.5% (w/w) aqueous 25 mM disodium hydrogen phosphate, pH 7.0, at a flow rate of 1 mL min−1. The method was evaluated according to criteria stated in FDA bioanalytical method validation guidance. The unique approach applied in this paper enables direct analysis of simvastatin and simvastatin acid, so the method can be used to obtain reliable results in a rapid and simple way.
Authors:B. Stojanović, Z. Marinković, G. Branković, and E. Fidančevska
The formation of TiO2 prepared by hydrolysis method was presented. Thermodynamics and kinetics of anatase crystallization reaction were investigated.
Differential method of kinetic data evaluation in non-isothermal conditions according toKissinger, Ozawa and Kazeev-Yerofeev
was applied. Starting, crystallized and thermally treated powders were determined using X-ray powder diffraction analysis.
The characteristic parameters (the activation energy, constant rate and formal kinetic order of reaction) of TiO2 formation were calculated using DSC data.
Authors:S. Vuckovic, I. Stojanovic, S. Prodanovic, B. Cupina, T. Zivanovic, S. Vojin, and S. Jelacic
Scop.) is the only species in the genus
. Sainfoin is a Eurasian perennial herb that has purple flowers, curved pods and is naturalized in Europe, Asia and North America grasslands on calcareous soil. Sainfoin has been grown in parts of Europe and Asia for hundreds of years. Understanding the relationships among sainfoin ecogeographic, and chemical characteristics may provide insights for better utilizing exotic germplasm. Ten sainfoin populations, were sampled and determined in Serbia and B&H. Some chemical properties, such as crude protein, ash, fat, crude fibre, phosphorus, calcium, magnesium, potassium, K/(Ca+Mg) ratio, and sulfur. Serbia is an important gene origin center for most legume species. Considering the high values of their traits, some Serbian sainfoin populations could serve as a valuable breeding material. In comparison with populations from other parts of the world, Serbian populations are superior in chemical properties and nutritional quality values.
Authors:M. Mašković, B. Jančić-Stojanović, A. Malenović, D. Ivanović, and M. Medenica
Robustness testing is an important part of method validation. Many ideas on robustness testing can be found in the literature, but the most useful approach is application of experimental design. In the work discussed in this paper, Plackett-Burman design was used for robustness testing of an LC method. Robustness was assessed for a previously validated method developed for chromatographic analysis of perindopril tert-butylamine and its impurities. Eleven factors (seven real and four dummies) in twelve experiments were examined. Robustness was assessed by graphical (half-normal probability plots and Pareto charts) and statistical (t-test) methods. For estimation of the standard error of effect (necessary for t-test estimation) calculations based on negligible effects and Dong's algorithm were used at the significance levels α= 0.05 and α = 0.01. In this way the effect of the factors was completely defined and, furthermore, nonsignificant intervals for significant variables were calculated. Finally, on the basis of the worst-case situation, system-suitability tests were performed and acceptance limits for certain values were calculated.