A method of controlling the impurities in a cyclosporin A eye gel. A high performance liquid chromatography is performed, and chromatographic conditions are as follows: the detection wavelength is 210-230 nm; the column temperature is 60-68? C.; the flow rate is 0.8-1 ml/min; and the mobile phase A is: THF-water-phosphoric acid. The method of controlling impurities solves the problem of excipients interference and separation of many impurities at the same time, it also provides an effective method for the formulation of quality standard of impurities in this kind of preparation.

In one aspect, disclosed herein is a method for determining sulfate concentration in a sample, comprising: a) providing a liquid sample comprising urea and at least one impurity; b) concentrating the liquid sample under conditions effective to reduce the liquid volume; c) forming a dilute sample solution by diluting the concentrated liquid sample of step b) in water; and d) analyzing the dilute sample solution of step c) with ion chromatography to determine if a concentration of sulfate is present in the provided liquid sample of step a); wherein the analyzing of step d) is capable of determining the presence of a sulfate concentration present in an amount less than about 1 ppm.

The invention provides a process of controlling the impurities of clindamycin hydrochloride, comprising a step of purifying said clindamycin hydrochloride by two-phase high performance liquid chromatography, wherein the chromatographic conditions are as follows: the detection wavelength is 200-220 nm; the column temperature is 20-40 C.; the flow rate is 0.8-1 ml/min; Mobile phase A: 0.025 mol/L potassium dihydrogen phosphate solution; Mobile phase B: Acetonitrile; and gradient elution is performed. The method of controlling impurities of the invention can solve the problem of the interference by excipients and the problem of the separation of many impurities at the same time. It also provides an effective method for setting quality standard of impurities in such a formulation.

An information processing device processes information based on a plurality of chromatograms obtained by analyzing a plurality of samples. A determination processing unit determines presence or absence of each of a plurality of target components in each sample based on the plurality of chromatograms. A list generation processing unit generates a list associating the plurality of target components with each sample and indicating the presence or absence of each of the plurality of target components in each sample determined by the determination processing unit. Checking the list enables prompt confirmation of the presence or absence of the target components in each of the plurality of samples.

The detection of minute amounts of components that have been undetectable due to an influence of a mobile phase or reagents or the like added to the mobile phase is realized in LC-MS. At the outset, blank measurement is executed, and an m/z value M.sub.BG of a background signal derived from a mobile phase or the like is extracted on a mass spectrum obtained by the blank measurement (S2-S4). An analysis method is then created that executes scanning measurement in a plurality of divided m/z ranges in which the m/z value M.sub.BG of the background signal has been excluded from a predetermined m/z range. An LC/MS analysis of the target sample is executed according to the analysis method (S5-S6). When a total ion chromatogram (TIC) is created from data obtained by the LC/MS analysis, influence of the background signal hardly appears in the TIC, and the base line is lowered.

Disclosed is a method for the determination of impurities in polyalkylene ethers and polyalkylene amines comprising the steps i) introducing polyalkylene ethers or polyalkylene amines as an analyte into a chromatography column containing monolithic silica gel as a stationary phase, ii) eluting the analyte with a liquid elution agent having such a polarity that the analyte is in adsorptive equilibrium with the stationary phase during chromatography, iii) detecting the components of the analyte at the exit-side end of the chromatography column, receiving a chromatogram, which shows different components of the analyte and its qualitative amount depending on the elution time of the individual components, and iv) identifying bands in the chromatogram having a low height or area compared to the band with the largest height or area as an indication of the presence of impurities in the analyte. The method allows in an easy manner to identify impurities in the sample. The method can be used for quality control but also for the preparative cleaning of the sample.

The present application relates to processes of preparing a plurality of porous sorptive solid phase microextraction (SPME) devices and also to the porous sorptive SPME devices prepared therefrom, including porous sorptive SPME metallic and fiberglass mesh supported devices. The present application also relates a method of using the porous sorptive SPME devices to extract one or more analytes from a sample matrix such as a bodily fluid or a water sample.

A chromatographic separation column for characterizing surfactant purity is disclosed. The column includes a separation medium having a particulate porous substrate with monofunctional silane with diisopropyl side chain groups and a pendant cyano functional group held within a column. The porous substrate has a pore size of about 50 ? to about 500 ? and an average particle size of about 1.0 ?m to about 100 ?m. The column has an inner diameter of about 1.0 to 100 mm, e.g., 4.6 mm and a length from about 10 mm to about 250 mm. Methods of facilitating characterization of polysorbate 80 by providing a sample containing polysorbate 80 and one or more reaction products of polysorbate 80 and a chromatographic separation column are disclosed. Methods of characterizing polysorbate 80 by separating polysorbate 80 and one or more reaction products of polysorbate 80 are also disclosed.

The present invention relates to an early warning method before the occurrence of aflatoxin contamination. The steps are as follows: extracting toxins from the sample to obtain a sample extract, and subjecting the sample extract to detection and analysis by liquid chromatography-high resolution mass spectrometer, performing qualitative analysis based on the mass spectrometry information to obtain qualitative results, performing quantitative analysis based on a standard curve of the chromatographic peak area of each warning molecule/the peak area of the internal standard-warning molecule concentration to obtain quantitative results of these warning molecules, wherein a risk of aflatoxin contamination of the sample is assessed to obtain a classification prediction model, inputting the quantitative results of the warning molecules for a toxigenic strain of Aspergillus flavus, and outputting a risk assessment result based on the classification prediction model, thereby achieving the early warning before aflatoxin contamination occurs.

This invention provides an isolated compound having the structure:

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or a salt thereof.

The invention also provides for a process for preparing 4-(3-(methylsulfonyl)phenyl)-1-propylpiperidin-4-ol, 1-(3,3-bis(3-(methylsulfonyl)phenyl)propyl)-4-(3-(methylsulfonyl) phenyl)piperidone, 1,4-bis((3-(1-propylpiperidin-4-yl)phenyl)sulfonyl)butane, (3R,4S)-4-(3-(methylsulfonyl)phenyl)-1-propylpiperidin-3-ol, 4-(3-(methylsulfonyl)phenyl)-1-propylpiperidine 1-oxide, 1-(2-methylpentyl)-4-(3-(methylsulfonyl)phenyl)piperidine, 4-(3-(methylsulfinyl)phenyl)-1-propyl-1,2,3,6-tetrahydropyridine, and 4-(3-(methylsulfonyl)phenyl)-1-propyl-1,2,3,6-tetrahydropyridine.

This invention also provides an impurity or a salt thereof for use, as a reference standard to detect trace amounts of the impurity in a pharmaceutical composition comprising pridopidine or a pharmaceutically acceptable salt thereof. This invention further provides a process for producing a pridopidine drug product comprising obtaining a pridopidine drug substance and. mixing the pridopidine drug substance with suitable excipients so as to produce the pridopidine drug product. This invention also provides a process for producing a pridopidine drug product. This invention also provides a process of distributing a pridopidine drug product.