A simple, fast and reliable reverse-phase high-performance liquid chromatographic (HPLC) method was developed for the assay of lidocaine hydrochloride (LH) in Gantrez-alginate microspheres. Separation was achieved in a LiChrospher C18 column, using a mobile phase consisting of acetonitrile:ammonium acetate (0.0257 M) adjusted to pH 4.85 with acetic acid, in the ratio 70:30 (v/v) and a flow rate of 0.6 mL/min. The detection was made with a diode array detector measuring at the maximum for the compound. The validation study demonstrated that the method was precise, accurate and linear over the concentration range of analysis with a limit of detection of 0.001 mg/mL. The limit of quantification was 0.002 mg/mL. Linear regression analysis in the range of 0.8-2.4 mg/mL gave correlation coefficients higher than 0.995. The method developed was applied to the analysis of lidocaine in microsphere samples in order to evaluate in next papers, the encapsulation efficiency of different formulations.
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http://dx.doi.org/10.1016/j.jpba.2008.01.045 | DOI Listing |
Foods
December 2024
Departamento de Química, Área de Química Analítica, Facultad de Ciencias, Universidad de La Laguna (ULL), Avenida Astrofísico Francisco Sánchez s/n, 38206 San Cristóbal de La Laguna, Tenerife, Spain.
In this work, two novel (-)-menthol-based hydrophobic natural eutectic solvents with vanillin and cinnamic acid were prepared and applied as extraction solvents. In this regard, 12 endocrine disruptors, including phenol, 2,4-dimethylphenol, 2,3,6-trimethylphenol, 4--butylphenol, 4--butylphenol, 4--amylphenol, 4--hexylphenol, 4--octylphenol, 4--heptylphenol, 4--octylphenol, and 4--nonylphenol and bisphenol A, were studied in a green tea drink. A temperature-controlled liquid-liquid microextraction was used as the extraction method, and nano-liquid chromatography-ultraviolet detection was used as the separation and determination system.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Laboratory of Organic Chemistry LR17ES08, Faculty of Sciences of Sfax, University of Sfax, B.P 1171, Sfax 3038, Tunisia.
Green chemistry focuses on reducing the environmental impacts of chemicals through sustainable practices. Traditional methods for extracting bioactive compounds from leaves, such as hydro-distillation and organic solvent extraction, have limitations, including long extraction times, high energy consumption, and potential toxic solvent residues. This study explored the use of supercritical fluid extraction (SFE), pressurized liquid extraction (PLE), and gas-expanded liquid (GXL) processes to improve efficiency and selectivity.
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December 2024
School of Public Health, Capital Medical University, Beijing 100069, China.
Oxysterols, as metabolites of cholesterol, play a key role in cholesterol homeostasis, autophagosome formation, and regulation of immune responses. Disorders in oxysterol metabolism are closely related to the pathogenesis of neurodegenerative diseases. To systematically investigate the profound molecular regulatory mechanisms of neurodegenerative diseases, it is necessary to quantify oxysterols and their metabolites in central and peripheral biospecimens simultaneously and accurately.
View Article and Find Full Text PDFMolecules
January 2025
School of Environmental and Materials Engineering, Yantai University, Yantai 264005, China.
This study systematically investigated the effect of organic solvent addition on the detection signal intensity of 15 organic pesticides in water using ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS). The analysis of chromatographic peak area ratios in ultrapure water (UPW) versus 30% methanol (MeOH)-UPW showed that the adsorption effects (AEs, mainly from injection vials with weaker polarity) were the main factor influencing the detection intensity of the organic pesticides. The AEs varied with pesticide type and concentration, especially for those with high logK values and longer retention times, such as malathion, triadimefon, prometryn, S-metolachlor, diazinon, and profenofos.
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December 2024
Department of Chemical Engineering, Campus de Espinardo, University of Murcia, 30100 Murcia, Spain.
The value of branched esters comes from the special properties they have in cold environments, which allow them to remain liquid over a wide range of temperatures. These properties make them useful for application in the cosmetic industry or as lubricant additives. This paper presents the studies carried out to ascertain the operational feasibility of the enzymatic esterification of 2-methylpentanoic acid (MPA) with 1,10-decanediol (DD), with the objective of obtaining a novel molecule: decane-1,10-diyl bis(2-methylpentanoate) (DDBMP).
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