Shades of red: A chemical exploration of pigments and dyes in 19th century postage stamps by a multi-analytical methodology.

A total of 57 European, Canadian and North American postage stamps, all in red shades, were analyzed with the main goal of unraveling which pigments or dyes were used to produce the red color in the period dated from 1841 to 1899. Both non-destructive techniques, including X-Ray Fluorescence (XRF), Fiber Optics Reflectance Spectra (FORS), and Steady State Fluorescence Spectroscopy, and destructive methods such as High-Performance Liquid Chromatography coupled with Diode-Array Detection (HPLC-DAD) and Electrospray Ionization High-Resolution Mass Spectrometry (ESI-HRMS), were utilized for a comprehensive analysis. The examined red shades were identified as originating from either a single pigment or dye, or a combination of both.

In vitro studies into establishing therapeutic bioequivalence of complex topical products: Weight of evidence.

Over the past decade, topically applied drug products have experienced extraordinary price increases, due to the shortage of multisource generic drug products. This occurrence is mainly related to the underlying challenges evolved in topical bioequivalence documentation. Although there has been continuing regulatory efforts to present surrogate in vitro methods to clinical endpoint studies, there is still a continued need for cost- and time-efficient alternatives that account for product specificities.

Selective, broad-spectrum antiviral photodynamic disinfection with dicationic imidazolyl chlorin photosensitizers.

The COVID-19 pandemic exposes our vulnerability to viruses that acquire the ability to infect our cells. Classical disinfection methods are limited by toxicity. Existing medicines performed poorly against SARS-CoV-2 because of their specificity to targets in different organisms.

Reactivity of ethyl nitrosoacrylate toward pyrrole, indole and pyrrolo[3,2-]carbazole: an experimental and theoretical study.

Nitrosoalkenes react with 8-methyl-1,6-dihydropyrrolo[3,2-]carbazole to give both 2- and 3-alkylated products via hetero-Diels-Alder reaction followed by the cycloadduct ring-opening. Quantum chemical calculations, at DFT level of theory, were carried out to investigate the regioselectivity of the cycloaddition of ethyl nitrosoacrylate with 1,6-dihydropyrrolo[3,2-]carbazoles as well as with pyrrole and indole, allowing a more comprehensive analysis of the reactivity pattern of nitrosoalkenes with five-membered heterocycles. Furthermore, theoretical calculations confirmed that ethyl nitrosoacrylate reacts with these heterocycles via a LUMO-HOMO controlled cycloaddition.

Fluorinated Mn(III)/(II)-Porphyrin with Redox-Responsive H and F Relaxation Properties.

A new fluorinated manganese porphyrin, (Mn-TPP-p-CF ) is reported capable of providing, based on the Mn(III)/Mn(II) equilibrium, dual H relaxivity and F NMR response to redox changes. The physical-chemical characterization of both redox states in DMSO-d /H O evidenced that the H relaxometric and F NMR properties are appropriate for differential redox MRI detection. The Mn(III)-F distance (d =9.

Drilling down the bioequivalence assessment of topical antifungal products: Microstructure and release.

In recent years, the regulatory mechanisms for topical generic product bioequivalence (BE) assessment have been subjected to noteworthy changes, with the FDA issuing product specific guidances, and the EMA adopting a more universal approach with the quality and equivalence of topical products draft guideline. The agencies advise on a modular strategy for BE documentation. Nevertheless, their scope, data analysis and criteria are rather distinct.

Reaction of Corroles with Sarcosine and Paraformaldehyde: A New Facet of Corrole Chemistry.

Details on the unexpected formation of two new (dimethylamino)methyl corrole isomers from the reaction of 5,10,15-tris(pentafluorophenyl)corrolatogallium(III) with sarcosine and paraformaldehyde are presented. Semi-empirical calculations on possible mechanism pathways seem to indicate that the new compounds are probably formed through a Mannich-type reaction. The extension of the protocol to the free-base 5,10,15-tris(pentafluorophenyl)corrole afforded an unexpected new seven-membered ring corrole derivative, confirming the peculiar behavior of corroles towards known reactions when compared to the well-behaved porphyrin counterparts.

Topical bioequivalence: Experimental and regulatory considerations following formulation complexity.

Documenting topical bioequivalence can be an extremely complex process, which is intrinsically dependent on the formulation technological features. According to EMA guideline, for simple formulations, BE may be demonstrated by documenting the qualitative (Q1), quantitative (Q2), microstructure (Q3) and performance (Q4) equivalence. Nevertheless, when addressing complex semisolids, equivalence regarding local availability should also be demonstrated.

Posttranslational modifications of proteins are key features in the identification of CSF biomarkers of multiple sclerosis.

Background: Multiple sclerosis is an inflammatory and degenerative disease of the central nervous system (CNS) characterized by demyelination and concomitant axonal loss. The lack of a single specific test, and the similarity to other inflammatory diseases of the central nervous system, makes it difficult to have a clear diagnosis of multiple sclerosis. Therefore, laboratory tests that allows a clear and definite diagnosis, as well as to predict the different clinical courses of the disease are of utmost importance.

Methods for unsupervised contribution analysis of raw EEM data in water monitoring. Contaminant identification and quantification.

Fluorescence EEM spectra provide the "fingerprint" of water contamination and is a very efficient way to access the quality of water bodies. These multivariate datasets correspond to complex mixtures and are very rich in information. Graphical approaches have been used for decades to characterize and quantify different contamination sources.

Removal of Imidacloprid from Water by Microalgae Nannochloropsis sp. and Its Determination by a Validated RP-HPLC Method.

The large-scale use of pesticides is one of the main causes of the dramatic degradation of our environment. Pesticides such as imidacloprid (IMID) have been linked to declines in bee health and toxicity to other beneficial insects. They pose a threat to human health due to their persistence in the environment and accumulation in the food chain.

Poly(β-cyclodextrin)-Activated Carbon Gel Composites for Removal of Pesticides from Water.

Pesticides are widely used in agriculture to increase and protect crop production. A substantial percentage of the active substances applied is retained in the soil or flows into water courses, constituting a very relevant environmental problem. There are several methods for the removal of pesticides from soils and water; however, their efficiency is still a challenge.

Photoacoustic method for real-time assessment of salt content in aqueous solutions.

In 2004, the Food and Drug Administration established the foundations for the application of process analytical technologies (PAT) in real-time control of the drug manufacturing process, where progress has been essentially directed to solid formulations. In order to enlarge the application of PAT principles to injectable drug products, the development of appropriate manufacturing process control tools is mandatory. Photoacoustics is a non-invasive technique with the potential for application in real-time control of the manufacturing process of injectable drug products.

Development and validation of a RP-HPLC method for the simultaneous analysis of paracetamol, ibuprofen, olanzapine, and simvastatin during microalgae bioremediation.

A rapid reverse phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous quantification of paracetamol, ibuprofen, olanzapine, simvastatin and simvastatin acid in the context of microalgae bioremediation. The method was validated according to the guidelines of the US Food and Drug Administration (FDA), the International Conference on Harmonization (ICH), and Eurachem with respect to system suitability, linearity, accuracy, precision, recovery, limits of detection and quantification, ruggedness, selectivity and specificity. The estimated limits of detection and quantification were, respectively, 0.

Diving into Batch-to-Batch Variability of Topical Products-a Regulatory Bottleneck.

Purpose: Following the recent European Medicine Agency (EMA) draft guideline on quality and equivalence of topical products, a modular framework for bioequivalence assessment is proposed, wherein the qualitative, quantitative, microstructure and product performance sameness is demanded to support generic applications. Strict regulatory limits are now imposed, but, the suitability of these limits has been subject of intense debate. In this context, this paper aims to address these issues by characterizing a panel of 8 reference blockbuster semisolid topical products.

Removal of Pharmaceuticals from Water by Free and Imobilised Microalgae.

Pharmaceuticals and their metabolites are released into the environment by domestic, hospital, and pharmaceutical industry wastewaters. Conventional wastewater treatment technology does not guarantee effluents of high quality, and apparently clean water may be loaded with pollutants. In this study, we assess the performance and efficiency of free and immobilised cells of microalgae sp.

Luminescent Properties of Lanthanoid-Poly(Sodium Acrylate) Composites: Insights on the Interaction Mechanism.

The interaction between polyelectrolytes and metal ions is governed by different types of interactions, leading to the formation of different phases, from liquid state to weak gels, through an appropriate choice of metal ion/polyelectrolyte molar ratio. We have found that lanthanide ions, europium(III) and terbium(III), are able to form polymer composites with poly(sodium acrylate). That interaction enhances the luminescent properties of europium(III) and terbium(III), showing that Eu/poly(sodium acrylate) (PSA) and Tb/PSA composites have a highly intense red and green emission, respectively.

Deep Learning for Deep Chemistry: Optimizing the Prediction of Chemical Patterns.

Computational Chemistry is currently a synergistic assembly between calculations, simulation, machine learning (ML) and optimization strategies for describing, solving and predicting chemical data and related phenomena. These include accelerated literature searches, analysis and prediction of physical and quantum chemical properties, transition states, chemical structures, chemical reactions, and also new catalysts and drug candidates. The generalization of scalability to larger chemical problems, rather than specialization, is now the main principle for transforming chemical tasks in multiple fronts, for which systematic and cost-effective solutions have benefited from ML approaches, including those based on deep learning (e.

Antibacterial Photodynamic Inactivation of Antibiotic-Resistant Bacteria and Biofilms with Nanomolar Photosensitizer Concentrations.

Gram-negative bacteria and bacteria in biofilms are very difficult to eradicate and are the most antibiotic-resistant bacteria. Therapeutic alternatives less susceptible to mechanisms of resistance are urgently needed to respond to an alarming increase of resistant nosocomial infections. Antibacterial photodynamic inactivation (PDI) generates oxidative stress that triggers multiple cell death mechanisms that are more difficult to counteract by bacteria.

aQbD as a platform for IVRT method development - A regulatory oriented approach.

The EMA draft guideline on quality and equivalence of topical products and the FDA non-binding product specific guidances release has encouraged the establishment of a regulatory background for in vitro release testing (IVRT). Herein, a novel framework applicable to the development of a discriminatory IVRT method is described, according to analytical quality by design (aQbD) principles. A commercially available diclofenac emulgel formulation was used as model product.

A novel Pd-catalysed sequential carbonylation/cyclization approach toward bis--heterocycles: rationalization by electronic structure calculations.

An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy, using carbon monoxide and structurally different aliphatic diamines as -nucleophiles, gives access, in one pot, to a new family of indole-based -heterocyclic derivatives (hydropyrazinones, benzodiazepinones and hydroquinoxalines). Optimization of the reaction conditions towards double carbonylation ( = 30 bar, = 80°C, iodoindole/diamine ratio = 1 : 1.5, toluene as solvent) allowed the target cyclic products, which are formed via intramolecular cyclization of the ketocarboxamide intermediates, to be obtained through a nucleophilic addition/elimination reaction with the pendant terminal amine groups.

Development of levofloxacin-loaded PLGA microspheres of suitable properties for sustained pulmonary release.

Aerosol antibiotics are an interesting alternative to oral or intravenous therapy in Cystic Fibrosis lung infections. Levofloxacin (LVX) inhaled solution is already an effective option. In this study, the aim was the development of LVX-loaded PLGA microspheres (MS) for pulmonary administration as a dry powder.

Host flexibility and space filling in supramolecular complexation of cyclodextrins: A free-energy-oriented approach.

Cyclodextrins (Cds) are versatile carbohydrate hosts for developing multifunctional nanostructures of pharmaceutical interest. Factors affecting the thermodynamic signatures and stability of β- and γ-Cd complexes are detailed at the atomic level. The MD/PMF-based method is combined with the description of the nature and strength of the inter-partner affinity.

Adsorption of charged macromolecules upon multicomponent responsive surfaces.

Adsorption of polyions onto charged surfaces has long been recognized as a crucial phenomenon in biological and technological applications. An intuitive model relating polyelectrolyte adsorption with the imposed features of polarizable surfaces of different compositions and charges is proposed based on Monte Carlo simulations using a coarse-grained approach. The excellent performance of the equation allows simultaneously describing a wide range of adsorption regimes and accounting for specific non-monotonic trends.

Analysis of raw EEM fluorescence spectra - ICA and PARAFAC capabilities.

Excitation-Emission fluorescence spectroscopy is a versatile technique and has been used to detect, characterize and quantify residual Dissolved Organic Matter (DOM) in aquatic domains. PARAllel FACtor Analysis (PARAFAC) has been extensively used in the analysis of excitation-emission matrices (EEM), allowing for a better identification and quantification of contributions resulting from spectral decomposition. In this work we have adapted Independent Component Analysis (ICA) in order to make it suitable to the analysis of three-way EEM datasets, and tested ICA and PARAFAC performances for the study of three available datasets (Claus, Dorrit and drEEM).