A quantitative validated method using liquid chromatography and chemometric analysis for evaluation of raw material oF Maytenus ilicifolia (Schrad.) Planch., Celastraceae

The hydroalcoholic extracts prepared from standard leaves of Maytenus ilicifolia and commercial samples of espinheira-santa were evaluated qualitatively (fingerprinting) and quantitatively. In this paper, fingerprinting chromatogram coupled with Principal Component Analysis (PCA) is described for the metabolomic analysis of standard and commercial espinheira-santa samples. The epicatechin standard was used as an external standard for the development and validation of a quantitative method for the analysis in herbal medicines using a photo diode array detector. This method has been applied for quantification of epicatechin in commercialized herbal medicines sold as espinheira-santa in Brazil and in the standard sample of M. ilicifolia

Combining the pharmacophore features of coumarins and 1,4-substituted 1,2,3-triazoles to design new acetylcholinesterase inhibitors : fast and easy generation of 4-methylcoumarins/1,2,3-triazoles conjugates via Click Chemistry

Coumarins are a large class of compounds that display a range of interesting biological properties, being considered privileged structures because of the ability of their 2H-chromen-2-one nuclei to bind to multiple pharmacological targets. We hypothesized that the linkage of a second pharmacophore nucleus to the 2H-chromen-2-one core, the 1,2,3-triazole moiety, would entail more selective and pharmacologically active coumarins. Therefore, we describe the synthesis of fourteen 4-methylcoumarins/1,4-substituted 1,2,3-triazole conjugates, which were predicted by in silico methods to inhibit acetylcholinesterase (AChE) and proved to be moderate in vitro inhibitors of this enzyme. Molecular docking simulations suggest that the most active of these compounds has a putative binding mode similar to donepezil, both occupying the peripheral anionic site of AChE, which is associated with the secondary noncholinergic functions of the enzyme. This highlights the potential of this series for further optimization in the search of new coumarins for the treatment of Alzheimer’s disease

Desenvolvimento de colunas cromatográficas de meios de acesso restrito proteína-imobilizada e suas avaliações para análise de fármacos com injeção direta de plasma humano

A series of bovine serum albumin-immobilized supports have been prepared and used as restricted access media (RAM) columns. Restricted-access supports combine size-exclusion of proteins and other high-molar-mass matrix components with the simultaneous enrichment of low-molar mass analytes. These characteristics were chromatographically evaluated for the columns. The RAM-BSA (Bovine Serum Albumin) columns showed excellent performance for exclusion of human plasma protein with good retention capacity for a series of acidic, basic, and neutral drugs

Fármacos, ETEs, e corpos hídricos

Na última década, especial atenção tem sido dada a presença de compostos farmacêuticos no ambiente aquático; uma vez que o aporte contínuo e a persistência de várias dessas substâncias podem trazer danos irreversíveis à biota. Sendo assim, o desenvolvimento e aplicação de novas tecnologias de tratamento que permitam a remoção ou diminuição desses contaminantes tem sido objeto de interesse na área de saneamento ambiental. Entretanto, a não existência de programas específicos de monitoramento nas ETEs, impossibilita a avaliação do comportamento dos fármacos nas plantas instaladas. O presente trabalho ilustra os principais fatores envolvidos no aporte desses contaminantes e apresenta um alerta do caminho a ser percorrido, na implementação de sistemas de tratamento adequados para minimizar a deterioração dos ecossistemas aquáticos

Multimilligram enantioresolution of sulfoxide proton pump inhibitors by liquid chromatography on polysaccharide-based chiral stationary phase

The enantiomers of sulfoxide proton pump inhibitors - omeprazole, lansoprazole, rabeprazole and Ro 18-5364 - were enantiomerically separated by liquid chromatography at multimilligram scale on a poly saccharide-based chiral stationary phase using normal and polar organic conditions as mobile phase. The values of the recovery and production rate were significant for each enantiomer; better results were achieved using a solid-phase injection system. However, this system was applied just for the enantionteric separation of omeprazole to demonstrate the applicability of this injection mode at milligram scale. The chiroptical characterization of the compounds was performed using a polarimeter and a circular dichroism detector. The higher enantiomeric purity obtained for the isolated enantiomers suggests that the methods here described should be considered as a simple and rapid way to obtain enantiomeric pure standards for analytical purpose. (C) 2007 Elsevier B.V. All rights reserved

Validação em métodos cromatográficos para análises de pequenas moléculas em matrizes biológicas Chromatographic methods validation for analysis of small molecules in biological matrices

<abstract language="eng">Chromatographic methods are commonly used for analysis of small molecules in different biological matrices. An important step to be considered upon a bioanalytical method's development is the capacity to yield reliable and reproducible results. This review discusses validation procedures adopted by different governmental agencies, such as Food and Drug Administration (USA), European Union (EU) and Agência Nacional de Vigilância Sanitária (BR) for quantification of small molecules by bioanalytical chromatographic methods. The main parameters addressed in this review are: selectivity, linearity, precision, accuracy, quantification and detection limits, recovery, dilution integrity, stability and robustness. Also, the acceptance criterions are clearly specified

Rapid ligand fishing for identification of acetylcholinesterase-binding peptides in snake venom reveals new properties of dendrotoxins.

Acetylcholinesterase (AChE) from Electrophorus electricus (eel) was immobilized on the surface of amino-modified paramagnetic beads to serve as a model for the development, validation and application of a new affinity-based ligand-fishing assay for the discovery of bioactive peptides from complex protein mixtures such as venoms. Nano liquid chromatography-mass spectrometry (nanoLC-MS) was used for the analysis of trapped peptides. Using enzyme-functionalized beads, the ligand-fishing assay was evaluated and optimized using a peptide reference mixture composed of one acetylcholinesterase binder (fasciculin-II) and five non-binders (mambalgin-1, angiotensin-II, bradykinin, cardiotoxin and α-bungarotoxin). As proof of concept, snake venom samples spiked with fasciculin-II demonstrated assay selectivity and sensitivity, fishing the peptide binder from complex venom solutions at concentrations as low as 1.0 μg/mL. As negative controls for method validation, venoms of four different snake species, not known to harbor AChE binding peptides, were screened and no AChE binders were detected. The applicability of the ligand fishing assay was subsequently demonstrated with venom from the black mamba, Jameson's mamba and western green mamba (Dendroaspis spp.), which have previously been reported to contain the AChE binding fasciculins. Unknown peptides (i.e. not fasciculins) with affinity to AChE were recovered from all mamba venoms tested. Tryptic digestion followed by nano-LC-MS analysis of the material recovered from black mamba venom identified the peptide with highest AChE-binding affinity as dendrotoxin-I, a pre-synaptic neurotoxin previously not known to interact with AChE. Co-incubation of AChE with various dendrotoxins in vitro revealed reduced inactivation of AChE activity over time, thus demonstrating that these toxins stabilise AChE. [Abstract copyright: Copyright © 2018. Published by Elsevier Ltd.