Development of a new chromatographic method for the determination of bakuchiol in cosmetic products

Abstract The aim of this study was to develop and validate a simple, fast, and universal reversed-phase high-performance liquid chromatography method with fluorescence detection for the quantitation and evaluation of the stability of bakuchiol in cosmetic products. The analyte was extracted by tetrahydrofuran and separated on a Zorbax Eclipse Plus C18 analytical column (100 × 4.6 mm, 3.5 μm particle size) by a gradient elution program with the mobile phase consisting of water and acetonitrile and a flow rate of 1.0 mL min−1. The column temperature was held at 25 °C and fluorescence detection was performed at excitation and emission wavelengths of 264 and 338 nm, respectively. The stability studies of bakuchiol in cosmetic products were conducted under various conditions, including thermal and photolytic degradation, according to International Conference on Harmonization Guidelines. The calibration curve was linear in the range of 0.5–50.0 μg g−1 with a correlation coefficient greater than 0.9999. The limits of detection and quantification of the method were 0.1 and 0.5 μg g−1, respectively. Recovery values were in the range of 93.37–106.39 μg g−1, with relative standard deviations less than 6%. The method has been successfully applied to analyze different types of cosmetic products and proved to be reliable

New psychoactive substances : cathinone and its derivatives

Cathinone is the major alkaloid found in the Catha edulis plant. The chemical structure of the cathinone is similar to amphetamine, and the difference in their structure is the presence of the ketone group in the beta side chain position. Synthetic derivatives belong to the novel group of psychoactive substances called “legal highs” or designer drugs. Synthetic cathinones are formed by modifications of the cathinone molecule consisting in the attachment of various substituents to the benzene ring and side chain and the use of a nitrogen atom to build the pyrrolidine ring. On this basis, these relationships can be divided into four main groups: N-alkylated, N-pyrrolidinyl, 3,4-methylenedioxy-N-alkylated and 3,4- methylenedioxy-N-pyrrolidinyl derivatives [1-2]. The simplicity of the synthesis and the availability of substrates favors the continuous process of modifying the cathinone derivatives covered by legal control. Therefore, continuous improvement of cathinone detection methods is extremely important for forensic chemistry. Cathinones easily penetrate the blood-brain barrier, inhibiting the uptake of neurotransmitters, including dopamine, serotonin or noradrenaline, and increase their concentration in the synaptic cleft. This leads to increased monoaminergic transmission in the central as well as in the peripheral nervous system, which entails a number of adverse effects [3]. In this article we described the pharmacokinetics, postulated neurochemical mechanisms and pharmacological and toxicological effects of cathinones. The current legal status of cathinone derivatives and selected synthesis methods was also discussed. We believe these information contribute improving public health and safety

Simultaneous Determination of Human Serum Albumin and Low-Molecular-Weight Thiols after Derivatization with Monobromobimane

Biothiols are extremely powerful antioxidants that protect cells against the effects of oxidative stress. They are also considered relevant disease biomarkers, specifically risk factors for cardiovascular disease. In this paper, a new procedure for the simultaneous determination of human serum albumin and low-molecular-weight thiols in plasma is described. The method is based on the pre-column derivatization of analytes with a thiol-specific fluorescence labeling reagent, monobromobimane, followed by separation and quantification through reversed-phase high-performance liquid chromatography with fluorescence detection (excitation, 378 nm; emission, 492 nm). Prior to the derivatization step, the oxidized thiols are converted to their reduced forms by reductive cleavage with sodium borohydride. Linearity in the detector response for total thiols was observed in the following ranges: 1.76–30.0 mg mL−1 for human serum albumin, 0.29–5.0 nmol mL−1 for α-lipoic acid, 1.16–35 nmol mL−1 for glutathione, 9.83–450.0 nmol mL−1 for cysteine, 0.55–40.0 nmol mL−1 for homocysteine, 0.34–50.0 nmol mL−1 for N-acetyl-L-cysteine, and 1.45–45.0 nmol mL−1 for cysteinylglycine. Recovery values of 85.16–119.48% were recorded for all the analytes. The developed method is sensitive, repeatable, and linear within the expected ranges of total thiols. The devised procedure can be applied to plasma samples to monitor biochemical processes in various pathophysiological states

The Structure of N-phenyl-pyrazoles and Indazoles: Mononitro, Dinitro, and Trinitro Derivatives

This review explores the heterocyclic family of N-nitrophenyl pyrazoles and indazoles covering mainly their structural aspects, with special emphasis on the X-ray diffraction data. NMR spectroscopy and the theoretical calculations will also be briefly summarized. The synthesis and reactivity aspects will be reported when they are specific to these compounds.This work has been supported by the Spanish Ministerio de Economía, Industria y Competitividad (CTQ2012-35513-C02-02, CTQ2014-56833-R) and Comunidad Autónoma de Madrid (S2013/MIT-2841, Fotocarbon). Computer, storage, and other resources from the CTI (CSIC) are gratefully acknowledged.Peer Reviewe