The physics of terrestrial radioactive contamination is complex, primarily due to the mixtures of radionuclides, their migration, the effects of soil chemistry, and the prevalent climate. Consequently, application of classical techniques is inappropriate in modeling such an environment. The classification of territories contaminated with radioactive isotopes is vital in establishing a detoxification plan. Application of the fractal geometry provides a good insight and helps in such classification. Several techniques are implemented to determine geometric aspects of contaminated fields, and these show a way to differentiate between natural and man-made isotopes.
According to the Russian State Pharmacopoeia (Issue 406, Ed. X), the content of the main substance in methylandrostenediol tablets (0.01 and 0.025 g) is determined by a cumbersome gravimetric method providing information on neither the homogeneity of the substance no the presence of foreign impurities.At the same time, in the Temporal Pharmacopoeial Issue VFS 42-2635-95, the methylandrostenediol drug substance is characterized by a polarimetric method of quantitative analysis, but this technique is not suited for the analysis of substance in tablets.As is known, HPLC is one of the main methods used for the analysis of steroidal preparations [1 -4]. However, no attempts at applying this method to the analysis ofmethylandrostenedioi substance and other medication forms were reported. The purpose of our work was to develop an HPLC procedure applicable to determination of the content of the main substance and impurities in methylandrostenediol tablets.
CHROMATOGRAPHY CONDITIONSThe work was performed on a Waters chromatographic system (USA) including a Waters Model 717-Plus autosampier, Waters Model 510 HPLC pump, and a Waters Model 486 spectrophotometric deteetor. A stainless steel chromatographic column (150 x 3.9 ram) was filled with a Symmetry Cis octadecylsilane sorbent with an average particle size of 5 Ixrn. The peak of methylandrostenediol in the chromatogram of a standard solution corresponded to not less than 4000 theoretical plates. The coefficient of separation of the peaks of methylandrostenediol and methyltestosterone was Rs ~ 2.4, as determined upon the chromatography of a mixture of 0.5 mg methylandrostenediol and 0.5 mg methyltestosterone in I ml acetonitrile (Fig. 1).The elution conditions were as follows: mobile phase, acetonitrile -water (36 : 64); elution rate, 1.5 ml / min; sample volume, 50 ~tl; detection wavelength, 200 urn. I "Akrikhin" Chemico-Pharmaceutical Joint-Stock Company, Staraya Kupavna, Moscow Oblast, Russia.The standard solution was prepared by the following proeedure: a weighted mount (50 mg) of methylandrostenediol (VFS 42-2635-95) is dried at a temperature of 100-105~ (to remove both adsorbed and crystallization water) and dissolved in 50 ml acetonitrile in a 100-ml measuring flask, after which the solvent is added exactly to the mark and the solution thoroughly stirred.The analytical procedure is as follows: 50/al of a sample solution (with a methylandrostenediol concentration about 0.5 mg / ml) and 50 ~tl of the standard solution are sequentially introduced into the sample input device of the chromatograph and a ehromatogram containing peaks of the main component (methylandrostenediol) and impurities is recorded. The relative standard deviation of the area under the methylandrostenediol peak of the sample, calculated using three sequential chromatograms of the standard methylandrostenediol solution, must not exceed 2.0%.We have selected a comparatively low value of the working wavelength 20.0 nm of the detector because the optical absorption of methylandrostenediol exhibits a m...
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