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31.
Vujić Z Mulavdić N Smajić M Brborić J Stankovic P 《Molecules (Basel, Switzerland)》2012,17(3):3461-3474
Experimental design method was used for HPLC determination of irbesartan and hydrochlorothiazide in combined dosage forms. The traditional approach for optimization of experiments is time-consuming, involves a large number of runs and does not allow establishing the multiple interacting parameters. The main advantages of the experimental design method include the simultaneous screening of a larger number of factors affecting response and the estimation of possible interactions. On the basis of preliminary experiments, three factors-independent variables were selected as inputs (methanol content, pH of the mobile phase and temperature) and as dependent variables, five responses (resolution, symmetry of irbesartan peak, symmetry of hydrochlorothiazide peak, retention factor of irbesartan and retention factor of hydrochlorothiazide) were chosen. A full 23 factorial design, where factors were examined at two different levels ("low" and "high") was used to determine which factors had an effect on the studied response. Afterwards, experimental design was used to optimize these influent parameters in the previously selected experimental domain. The novelty of our method lies in the optimization step accomplished by Derringer's desirability function. After optimizing the experimental conditions a separation was conducted on a Supelcosil C(18) (150 mm × 4.6 mm, 5 mm particle size) column with a mobile phase consisting of methanol-tetrahydrofuran-acetate buffer 47:10:43 v/v/v, pH 6.5 and a column temperature of 25 °C. The developed method was successfully applied to the simultaneous separation of these drug-active compounds in their commercial pharmaceutical dosage forms. 相似文献
32.
JPC – Journal of Planar Chromatography – Modern TLC - A method for chromatographic separation of the enantiomers of (±)-metoprolol tartrate (±MeT) employing a chiral mobile... 相似文献
33.
It is analyzed how Debye-Waller factor measurements by Mössbauer experiments can yield information on the dynamics of undercooled liquids which is related to the formation of a glassy state. 相似文献
34.
D.?Aumiler T.?Ban N.?Vuji?i? S.?Vdovi? H.?Skenderovi? G.?Pichler 《Applied physics. B, Lasers and optics》2009,97(3):553-560
We introduce a method for determination of the absolute frequencies of comb lines within an optical frequency comb spectrum.
The method utilizes the experimental and theoretical approach of the velocity-selective optical pumping of the atomic ground
state hyperfine levels induced by resonant pulse-train excitation. The information on the laser pulse repetition frequency
and carrier–envelope offset are physically mapped onto the 87Rb ground state hyperfine level population velocity distributions. Theoretical spectra are calculated using an iterative analytic
solution of the optical Bloch equations describing the resonant pulse-train excitation of four-level 87Rb atoms. They are employed to fit the measured spectra and obtain the parameters of the frequency comb, thus providing a
practical algorithm which can be used in real-time measurements. 相似文献
35.
D. Nikoli? Z. Mijatovi? R. Kobilarov B. Vuji?i? M. ?irišan 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,86(3):285-298
This paper presents the results of the ion-broadening parameter A determination from experimental profiles of several neutral argon lines. Advanced deconvolution procedure has been used for parameter A determination. Experimental results have been obtained from the wall-stabilized pure argon plasma with electron density range (0.74-2.90) and temperature range 9280-. These results are compared with available theoretical and other experimental data. 相似文献
36.
The dependence of the Stark width of the spectral line of He II P
468.6 nm on the electron concentration in the laser plasma of helium for the range of electron densities N
e = (1–10)·1023 m–3 and electron temperatures of the order of 60 kK has been measured. The results obtained correspond well to Griem's theoretical data. An empirical relation is suggested which makes it possible to reliably determine the electron concentration from measured halfwidths in the investigated range of N
e. 相似文献
37.
G. M. Vuji
i 《Solid State Communications》1991,80(12):1001-1002
Assuming the presence of electron double-well potential in high-Tc oxide superconductors, we examine the low-lying electron excitations of the tunneling type as a mechanism of superconductivity. 相似文献
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39.
Two flavonoids, rutin and hesperidin, were investigated in vitro for anticoagulant activity through coagulation tests: activated partial thromboplastin time (aPTT), prothrombin time (PT) and thrombin time (TT). Only an ethanolic solution of rutin at the concentration of 830 μM prolonged aPTT, while TT and PT were unaffected. In order to evaluate whether the prolongation of aPTT was due to the decrease of coagulation factors, the experiment with deficient plasma was performed, showing the effects on factors VIII and IX. Since pharmacological activity of flavonoids is believed to increase when they are coordinated with metal ions, complexes of these flavonoids with Al(III) and Cu(II) ions were also tested. The results showed that complexes significantly prolonged aPTT and had no effects on PT and TT. Assay with deficient plasma (plasma having the investigated factor at less then 1%) revealed that complexes could bind to the coagulation factors, what may lead to a non-specific inhibition and aPTT prolongation. An effort was made to correlate stability of complexes with their anticoagulant properties. 相似文献
40.
Krešimir Molčanov Tomislav Portada Vesna Čaplar Milan Jokić Janja Makarević Nataša Šijaković Vujičić Zoran Štefanić Mladen Žinić Biserka Kojić-Prodić 《Structural chemistry》2013,24(2):597-609
Preparation, structural characterisation and topology of hydrogen bonding networks of bis(phenylglycinol)malonamide, as well as its Cα mono- and dialkyl-substituted derivatives are described. Their hydrogen bonding motifs are described in view of their gelling properties. Topology of hydrogen bonding typical of malonamide gelators is compared with those of well-examined oxalamide gelators. 相似文献