Compliance of commercial bleaches and stability of 1 g/L-dilutions using different sources of drinking water / Conformidad de lavandinas comerciales y estabilidad de diluciones 1g/L utilizando diferentes fuentes de agua potable

Introducción y Objetivos: En el contexto de COVID-19, la Organización Mundial de la Salud recomienda el uso de soluciones de hipoclorito de sodio 1 g/L, como una concentración capaz de inactivar el SARS-CoV-2 y la gran mayoría de patógenos presentes en el entorno sanitario. En consecuencia, hay un renovado interés en realizar estudios de estabilidad de estas disoluciones. El objetivo de este trabajo es verificar la concentración de cloro activo en varias marcas comerciales de hipoclorito de sodio y proponer una fecha límite de uso para soluciones de 1 g/L, obtenidas por dilución con agua potable proveniente de diferentes fuentes.Métodos: La concentración de cloro activo de preparaciones comerciales con concentración nominal entre 25-60 g/L fue valorada por titulación iodométrica. A partir de una de las marcas comerciales se prepararon diluciones de 1 g/L usando agua proveniente de diferentes plantas potabilizadoras en Córdoba, Argentina. Las disoluciones se almacenaron a temperatura ambiente, tanto expuestas como protegidas de la luz y fueron posteriormente tituladas a intervalos de tiempo preestablecidos. La fecha límite de uso se alcanzó cuando la concentración de cloro activo cayó por debajo del 90 % de la inicial.Resultados: La concentración de cloro activo en las soluciones comerciales estuvo dentro de los valores establecidos por la normativa vigente. Las diluciones protegidas de la luz mostraron una disminución menor al 10 % en la concentración de cloro activo durante los primeros 10 días de ensayo. (AU)

Introduction and objectives: In the context of COVID-19, the World Health Organization has recommended the use of extemporaneously prepared bleach solutions of 1 g/L, as a conservative concentration able to inactivate SARS-CoV-2 and the vast majority of other pathogens that may be present in the healthcare setting. Consequently, there is a renewed interest in conducting stability studies of these solutions. The goal of this work was to verify the available chlorine concentration in several bleach solutions trademarks and to propose a beyond use date for 1 g/L bleach solutions, obtained after dilution with drinking water from different sources.Methods: Bleach trademarks, with nominal concentrations between 25-60 g/L, were subjected to iodometric titration to determine the available chlorine concentration. One trademark was used to prepare 1 g/L dilutions using water from different purification plants in Córdoba, Argentina. The samples were stored at room-temperature, both exposed or protected from light. The available chlorine concentration was determined by titration at preestablished time intervals. The beyond use date was reached when the available chlorine concentration dropped below 90 % of its initial.Results: The concentration of active chlorine in the different trademark bleaches was within the values established by current regulations. Diluted solutions protected from light showed a decrease of less than 10 % in active chlorine concentration during the first 10 days of assay. However, one sample exceeded the acceptance limit after 14 days. In contrast, in the samples exposed to light, the concentration of active chlorine dropped to 96.4 % at 24 hours and 79.3 % after 48 hours. (AU)

Fluorescent Multifunctional Organic Nanoparticles for Drug Delivery and Bioimaging: A Tutorial Review.

Fluorescent organic nanoparticles (FONs) are a large family of nanostructures constituted by organic components that emit light in different spectral regions upon excitation, due to the presence of organic fluorophores. FONs are of great interest for numerous biological and medical applications, due to their high tunability in terms of composition, morphology, surface functionalization, and optical properties. Multifunctional FONs combine several functionalities in a single nanostructure (emission of light, carriers for drug-delivery, functionalization with targeting ligands, etc.), opening the possibility of using the same nanoparticle for diagnosis and therapy. The preparation, characterization, and application of these multifunctional FONs require a multidisciplinary approach. In this review, we present FONs following a tutorial approach, with the aim of providing a general overview of the different aspects of the design, preparation, and characterization of FONs. The review encompasses the most common FONs developed to date, the description of the most important features of fluorophores that determine the optical properties of FONs, an overview of the preparation methods and of the optical characterization techniques, and the description of the theoretical approaches that are currently adopted for modeling FONs. The last part of the review is devoted to a non-exhaustive selection of some recent biomedical applications of FONs.

Anti-tuberculosis site-specific oral delivery system that enhances rifampicin bioavailability in a fixed-dose combination with isoniazid.

The in vivo release segregation of rifampicin (RIF) and isoniazid (INH) has been proposed as a strategy to avoid RIF acid degradation, which is known as one of the main factors for reduced RIF bioavailability and can result in drug-resistant tuberculosis. So far, this strategy has been scarcely explored. The aims of this study were to investigate the stability and bioavailability of RIF after combination of a very fast release matrix of RIF with a sustained delivery system of INH. A series of INH-alginic acid complexes (AA-INH) was obtained and characterized. Independent and sequential release profile of AA-INH at biorrelevant media of pH 1.20 and 6.80 was explored. In addition, AA-INH was combined with a RIF-carboxymethylcellulose very fast release complex (CMC-RIF) obtained previously and subjected to acid dissolution assays to evaluate RIF acid stability and determine RIF and INH dissolution efficiencies. Finally, a pharmacokinetic study in dogs was carried out. The AA-INH was easily obtained in solid-state. Their characterization revealed its ionic nature, with a loading capacity of around 30%. The dissolution efficiencies (15 min) confirmed release segregation in acid media with 7.8 and 65.6% for AA-INH and CMC-RIF, respectively. INH release rate from the AA-INH system was slow in acid media and increased in simulated intestinal media. The complete release of INH was achieved after 2 h in simulated intestinal media in the sequential release experiments. The acid degradation of RIF was significantly reduced (36.7%) when both systems were combined and oral administration to dogs revealed a 42% increase in RIF bioavailability. In conclusion, CMC-RIF and AA-INH may be useful for the formulation of a site-specific solid dosage form to overcome some of the main obstacles in tuberculosis treatment. Graphical abstract.

Compliance of commercial bleaches and stability of 1 g/L-dilutions using different sources of drinking water / Conformidad de lavandinas comerciales y estabilidad de diluciones 1g/L utilizando diferentes fuentes de agua potable

INTRODUCTION AND OBJECTIVES: In the context of COVID-19, the World Health Organization has recommended the use of extemporaneously prepared bleach solutions of 1 g/L, as a conservative concentration able to inactivate SARS-CoV-2 and the vast majority of other pathogens that may be present in the healthcare setting. Consequently, there is a renewed interest in conducting stability studies of these solutions. The goal of this work was to verify the available chlorine concentration in several bleach solutions trademarks and to propose a beyond use date for 1 g/L bleach solutions, obtained after dilution with drinking water from different sources. METHODS: Bleach trademarks, with nominal concentrations between 25-60 g/L, were subjected to iodometric titration to determine the available chlorine concentration. One trademark was used to prepare 1 g/L dilutions using water from different purification plants in Córdoba, Argentina. The samples were stored at room-temperature, both exposed or protected from light. The available chlorine concentration was determined by titration at preestablished time intervals. The beyond use date was reached when the available chlorine concentration dropped below 90 % of its initial. RESULTS: The concentration of active chlorine in the different trademark bleaches was within the values established by current regulations. Diluted solutions protected from light showed a decrease of less than 10 % in active chlorine concentration during the first 10 days of assay. However, one sample exceeded the acceptance limit after 14 days. In contrast, in the samples exposed to light, the concentration of active chlorine dropped to 96.4 % at 24 hours and 79.3 % after 48 hours. No differences related to drinking water sources were observed. CONCLUSIONS: Compliance of the nominal available chlorine concentration in trademark bleach solutions was confirmed. Regardless the water source used for dilution, 1 g/L bleach solutions were stable for 10 days when stored at room temperature and protected from light. Instead, solutions exposed to light maintain their available chlorine concentration for only 24 hours

INTRODUCCIÓN Y OBJETIVOS: En el contexto de COVID-19, la Organización Mundial de la Salud recomienda el uso de soluciones de hipoclorito de sodio 1 g/L, como una concentración capaz de inactivar el SARS-CoV-2 y la gran mayoría de patógenos presentes en el entorno sanitario. En consecuencia, hay un renovado interés en realizar estudios de estabilidad de estas disoluciones. El objetivo de este trabajo es verificar la concentración de cloro activo en varias marcas comerciales de hipoclorito de sodio y proponer una fecha límite de uso para soluciones de 1 g/L, obtenidas por dilución con agua potable proveniente de diferentes fuentes. MÉTODOS: La concentración de cloro activo de preparaciones comerciales con concentración nominal entre 25-60 g/L fue valorada por titulación iodométrica. A partir de una de las marcas comerciales se prepararon diluciones de 1 g/L usando agua proveniente de diferentes plantas potabilizadoras en Córdoba, Argentina. Las disoluciones se almacenaron a temperatura ambiente, tanto expuestas como protegidas de la luz y fueron posteriormente tituladas a intervalos de tiempo preestablecidos. La fecha límite de uso se alcanzó cuando la concentración de cloro activo cayó por debajo del 90 % de la inicial. RESULTADOS: La concentración de cloro activo en las soluciones comerciales estuvo dentro de los valores establecidos por la normativa vigente. Las diluciones protegidas de la luz mostraron una disminución menor al 10 % en la concentración de cloro activo durante los primeros 10 días de ensayo. Sin embargo, una muestra superó el límite de aceptación luego de 14 días. En contraste, en las muestras expuestas a la luz, la concentración de cloro activo cayó a 96.4 % a las 24 horas y 79.3 % después de 48 horas. No se observaron diferencias relacionadas con las fuentes de agua potable. CONCLUSIONES: se confirmó la concentración nominal de cloro activo en todas las marcas comerciales evaluadas. Independientemente de la fuente de agua potable utilizada para la dilución, las soluciones de 1 g/L fueron estables durante 10 días cuando se almacenaron a temperatura ambiente y protegidas de la luz. En contraste, las soluciones expuestas a la luz mantienen la concentración de cloro activo durante solo 24 horas