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Method of determining content of hydroxymethyl quinoxyline dioxide and impurities thereof by hplc Determination is carried out by high performance liquid chromatography (HPLC) on a C18 column measuring 50×3.0 mm, filled with a carrier with grain size of 3.0 mcm, or measuring 150×4.6 mm, filled with a carrier with grain size of 5.0 mcm, using as the mobile phase a mixture of water and acetonitrile in ratio of 90:10 to 95:5 or a mixture of 0.3% methanoic acid solution and acetonitrile in ratio of 90:10 to 95:5 and acetonitrile in linear gradient mode on a chromatograph using a UV detector. |
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Method of determining hexoses in supramolecular structures of cells in escherichia coli Invention relates to biochemistry and molecular biology. Conservation of cells of Escherichia coli in presence of buffered 80-90% glycerol is performed. Cell envelopes are removed with 3% triton X-100. Cell supramolecular structures are successively extracted with increasing concentrations of salts: 0.14 M (bacterioplasm), 0.35 M (loosely linked with cell residue), 2 M NaCl (strongly linked with cell residue), and 6 M guanidine hydrochloride with 0.1% β-mercaptoethanol (cell residue). Acid hydrolysis is carried out in said fractions. Anthrone method is carried out, with preliminary purification of anthrone preparation. Calibration graph is built and quantity of hexoses is determined by means of calculation formula. |
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Present invention pertains to analytical chemistry, and particularly to methods of determining the quantitative composition of multi-component medicinal preparations with antithermic and antiallergic action. The method is achieved through inversed-phase high-efficiency liquid chromatography with an ultraviolet spectrophotometric detector and a chromatograph column, filled with a Zorbax SB C8 sorbent, in a linear concentration gradient mode of acetonitrile in a mobile phase during analysis. The mobile phase is a mixture of acetonitrile and a phosphate buffer solution. The content of defined components is calculated from the surface area of peaks on the chromatograms of the test solution and solution of working standard samples. With the objective of efficient separation of peaks of all active and auxiliary substances, the content of the mobile phase during analysis is changed from a phosphate buffer solution with pH 3.0 to a mixture of acetonitrile with a phosphate buffer solution with pH 6.8 in volume ratio of 1:4. |
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Invention proposes a method for simultaneous determination of composition of multicomponent medicinal preparations by reversed HPLC method with ultraviolet detector. Method is used in carrying out analysis of preparations comprising the following drugs: (1) paracetamol, propifenazone, caffeine, phenobarbital, codeine phosphate; or (2) paracetamol, ascorbic acid, codeine phosphate, phenylephrine hydrochloride, chlorphenylamine maleate; or (3) paracetamol, theophylline, caffeine, phenobarbital, ephedrine hydrochloride; or (4) codeine phosphate, nipagin, nipazol for a single stage in linear gradient regimen wherein the composition of mobile phase changes from phosphate buffer solution with pH 3.0 to its mixture with acetonitrile taken in the volume ratio = 1:1. Invention provides the complete separation of peaks of all analyzed and interfering substances and to obtain precise quantitative results. |
Another patent 2513064.