An embodiment of an analysis system can include an initial multi-port valve, at least one intermediate multi-port valve, a further multi-port valve, and a time-of-flight mass spectrometer (TOF-MS). The initial multi-port valve can be configured to receive a sample. The at least one intermediate multi-port valve can be fluidly connected to the initial multi-port valve and configured to receive the sample from the initial multi-port valve. A given intermediate multi-port valve can have an ion-exchange column associated therewith. The given intermediate multi-port valve can be configured selectably to one of direct the sample through the ion-exchange column associated therewith (in a speciation mode) or bypass the ion-exchange column (in an infusion mode). The further multi-port valve can be fluidly connected with the at least one intermediate multi-port valve and configured to receive the sample from therefrom. The time-of-flight mass spectrometer (TOF-MS) can be fluidly connected to the further multi-port valve.

An improved analytical method for analysis of dianhydrogalactitol preparations provides a method for determining the purity of dianhydrogalactitol and detecting impurities in preparations of dianhydrogalactitol, as well as identifying any such impurities. The method employs high performance liquid chromatography (HPLC), in particular, HPLC with refractive index (RI) detection; the HPLC can be followed by tandem mass spectroscopy. The method can further comprise the step of performing preparative HPLC collection of at least one specific substance peak present in a preparation of dianhydrogalactitol.

This invention provides an isolated compound having the structure: ##STR00001##
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-tetrahydropyridne, 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.

An improved analytical method for analysis of dianhydrogalactitol preparations provides a method for determining the purity of dianhydrogalactitol and detecting impurities in preparations of dianhydrogalactitol, as well as identifying any such impurities. The method employs high performance liquid chromatography (HPLC), in particular, HPLC employing a reverse phase amide column with ELSD detection; the HPLC can be followed by tandem mass spectroscopy. The method can further comprise the step of performing preparative HPLC collection of at least one specific substance peak present in a preparation of dianhydrogalactitol.

Methods are described for determining the quality of dioctyltin bisoctylmaleate and selectively screening its use as a component or modifying agent in a polymer production process. The quality of dioctyltin bisoctylmaleate is determined by measuring the presence and intensity of by products or impurities contained in the dioctyltin bisoctylmaleate. The detected impurities are resolved by comparison to a baseline, such as a solubility limit, to make a decision if the dioctyltin bisoctylmaleate supply is within acceptable limits. Selectively using certain supplies of dioctyltin bisoctylmaleate having suitable limits of impurities, such as the solubility limit of dioctyltin maleate, polymer production efficiency, time and costs can be improved.

A method for analyzing related substances in a pharmaceutical composition containing an amphiphilic block copolymer comprising a hydrophilic block and a hydrophobic block as a polymeric drug carrier, related substances identified thereby, and a method for evaluating a pharmaceutical composition by using the same are provided.

This disclosure provides methods and devices for quantitating, separating and/or detecting water in a liquid, gas or solid sample comprising one or more chemicals, the method comprising: providing the liquid, gas or solid sample comprising water and the one or more chemicals; and exposing said liquid, gas or solid sample to at least one solid support including at least one dicationic and/or tricationic species of Formula I or II adsorbed, absorbed or immobilized on the solid support.

The present disclosure describes a computer implemented method, a system, and a computer program product of controlling the purification of a macromolecule solution via real-time multi-angle light scattering.

The present invention relates to methods of determining the purity of a sample of 3,4-diaminopyridine comprising determining the presence, absence, or amount of a dimer of 3,4-diaminopyridine or a dimer of 3,4-diaminopyridine in the form of a salt, solvate or complex or a combination thereof. The invention also relates to methods of detecting and quantitating degradation in a sample of 3,4-diaminopyridine. Dimers of 3,4-diaminopyridine and methods of making and isolating the same are also provided.

A sorbent tube holder (100) for securing a sorbent tube (10) in position in a fluid-flow system, the sorbent tube holder (100) comprising: an mounting element (126) having first and second opposed ends (126a, 126b) which define a tube mounting axis (A-A); at least one fastener (128) in communication with the mounting element (126) for providing a releasable tube retaining force; at least one sorbent tube (10) engaged with the mounting element (126); and a holder frame (130) to which the mounting element (126) is attached to prevent or limit movement of the mounting element (126) perpendicular to the tube mounting axis. A method of preventing or limiting unintentional damage to a sorbent tube, and a portable tube holder are also provided.