Optimization of methods of quality control drug steroid structure for example glucocorticosteroid

This paper presents an original method for the analysis of corticosteroids with the use of reversed-phase high performance liquid chromatography. A mixture of 1% aqueous formic acid and ethyl alcohol at a ratio of 10 to 90 was taken as an eluting system for corticosteroids. This ratio of solvents in the mobile phase ensures control of the rate of movement of corticosteroids in the column. Since corticosteroids are freely soluble in alcohol, using 90% of this solvent in the mobile phase ensured optimum retention time of these compound

Determination of fracture mechanics parameters on a base of local displacement measurements

New experimental technique for a determination of the stress intensity factor (SIF) and T-stressvalues is developed and verified. The approach assumes combining the crack compliance method and opticalinterferometric measurements of local deformation response on small crack length increment. Initialexperimental information has a form of in-plane displacement component values, which are measured byelectronic speckle-pattern interferometry at some specific points located near a crack tip. Required values offracture mechanics parameters follow from the first four coefficients of Williams’ series. A determination ofinitial experimental data at the nearest vicinity of notch tip is the main feature of the developed approach. Thatis why it is not necessary to involve complex numerical models, which include global geometrical parameters,loading and boundary conditions of the object under study, in a stage of experimental data interpretation. Anavailability of high-quality interference fringe patterns, which are free from rigid-body motions, serves as areliable indicator of real stress state around a crack tip. A verification of the technique is performed bycomparing experimental results with analogous data of FEM modelling. Experimentally determined mode I SIFfor DCB specimen with end crack is in 5 per cent agreement with the numerically simulated case. Proposedapproach is capable of estimating an influence of the notch radius on fracture mechanics parameters.Comparing SIF and T-stress obtained for U-notches of different radius both in actual and residual stress fieldconfirms this statement

Analysis of optical magnetoelectric effect in GaFeO_3

We study the optical absorption spectra in a polar ferrimagnet GaFeO_3. We consider the E1, E2 and M1 processes on Fe atoms. It is shown that the magnetoelectric effect on the absorption spectra arises from the E1-M1 interference process through the hybridization between the 4p and 3d states in the noncentrosymmetry environment of Fe atoms. We perform a microscopic calculation of the spectra on a cluster model of FeO_6 consisting of an octahedron of O atoms and an Fe atom displaced from the center with reasonable values for Coulomb interaction and hybridization. We obtain the magnetoelectric spectra, which depend on the direction of magnetization, as a function of photon energy in the optical region 1.0-2.5 eV, in agreement with the experiment.Comment: 18 pages, 5 figure

Simplified mathematical modeling of the distribution process of licuroside and glycyram between the extractant and Glycyrrhizae radices

Theoretical development of the extraction process is an important task for further modeling and calculation of optimal conditions for extraction of biologically active compounds from the plant raw material. The aim of the study was to propose and test a theoretical model to describe the process of Licuroside and Glycyram distribution between the solid phase of Glycyrrhiza radices and the extractant. For studies, we used Glycyrrhiza radices (Liquorice roots). For extraction, we used plant raw material with particle size of 0.1-0.5 mm, and ethanol-water solution 70 % v/v was used as an extractan

Polyphenolic Compounds Composition Study in Ocimum basilicum L. Herb and the Development of Their Quantification Assessment

The article demonstrates the study results of the garden basil chemical composition - Ocimum basilicum L. It is established that the basic polyphenols of a plant are hydroxycinnamic acids - rosemary, caftaric, chlorogenic. Flavonoids, the dominant of which is routine, are presented in smaller quantities. An optimal method for the quantitative determination of O. basilicum L. polyphenols is offere