An isocratic, reversed-phase HPLC method was developed for the determination of the rates of purine and pyrimidine efflux during early reperfusion of isolated organs after non-perfusion cold conservation. The method enables determination of uric acid, cytidine, xanthine, hypoxanthine, uridine, AMP, inosine, and adenosine in liver perfusate using a standard C-18 column (25 cm length). Peaks are resolved by elution with buffer containing 1% acetonitrile, 20 mM potassium citrate (pH 6.25), and 25-55 mM tetramethylammonium. The effects of pH and solvents on peak retention times are described. As an example of the application of the method, the effects of allopurinol on the rates of postischemic efflux of purines and pyrimidines during reperfusion of liver stored in the cold for 24 h in Euro-Collins solution was studied.
Download full-text PDF |
Source |
---|
J Chromatogr A
December 2024
Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
Reversed-phase liquid chromatography (RPLC) offers significant advantages over traditional methods for estimating octanol-water partition constants, which are a critical parameter in drug discovery. In contrast to classical methods for determining the octanol-water partition constant, such as shake-flask techniques, RPLC is less time-consuming and easier to automate. In this study, we explored three alternative organic solvent modifiers: acetone, 2-propanol, and tetrahydrofuran for the indirect determination of the octanol-water partition constant for neutral compounds by RPLC using either isocratic retention factors or retention factors extrapolated to 100 % water for several stationary phases.
View Article and Find Full Text PDFSci Rep
November 2024
Department of Pharmaceutical Chemistry, Semmelweis University, Hőgyes E. u. 9, Budapest, 1092, Hungary.
In this study, a direct HPLC method was developed to determine the enantiomeric purity of the immunomodulatory drug, ozanimod. A systematic method development process was followed, incorporating risk assessment, identification of critical analytical procedure parameters, initial screening of stationary phases, and software-assisted optimization of method parameters. Eight different polysaccharide-based chiral columns were selected to assess chiral separation of enantiomers under polar organic elution mode.
View Article and Find Full Text PDFJ Chromatogr A
December 2024
Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
We performed multiscale simulations of analyte sorption and diffusion in hierarchical porosity models of monolithic silica columns for reversed-phase liquid chromatography to investigate how the mean mesopore size of the chromatographic bed and the analyte-specific interaction with the chromatographic interface influence the analyte diffusivity at various length scales. The reproduced experimental conditions comprised the retention of six analyte compounds of low to moderate solute polarity on a silica-based, endcapped, C stationary phase with water‒acetonitrile and water-methanol mobile phases whose elution strength was varied via the volumetric solvent ratio. Detailed information about the analyte-specific interfacial dynamics received from molecular dynamics simulations was incorporated through appropriate linker schemes into Brownian dynamics diffusion simulations in three hierarchical porosity models received from physical reconstructions of silica monoliths with a mean macropore size of 1.
View Article and Find Full Text PDFMedicina (Kaunas)
October 2024
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia.
Anal Chem
October 2024
Dow, Core R&D Analytical Science, Rheingaustr. 34, 65201 Wiesbaden, Germany.
This paper describes an approach to achieve low parts per billion (ppb) concentration level detection using a reversed-phase ultrahigh-performance liquid chromatographic ultraviolet absorbance detection method with large-volume feed injection (FI) for analytes in dichloromethane (DCM). FI is a novel technology that allows sample injection at a defined speed into the LC mobile phase. We demonstrate this approach for a mixture of bisphenol A and its diglycidyl ether derivatives in DCM.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!