Hierarchical Nanobiosensors at the End of the SARS-CoV-2 Pandemic.

Nanostructures have played a key role in the development of different techniques to attack severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Some applications include masks, vaccines, and biosensors. The latter are of great interest for detecting diseases since some of their features allowed us to find specific markers in secretion samples such as saliva, blood, and even tears. Herein, we highlight how hierarchical nanoparticles integrated into two or more low-dimensional materials present outstanding advantages that are attractive for photonic biosensing using their nanoscale functions. The potential of nanohybrids with their superlative mechanical characteristics together with their optical and optoelectronic properties is discussed. The progress in the scientific research focused on using nanoparticles for biosensing a variety of viruses has become a medical milestone in recent years, and has laid the groundwork for future disease treatments. This perspective analyzes the crucial information about the use of hierarchical nanostructures in biosensing for the prevention, treatment, and mitigation of SARS-CoV-2 effects.

New Method for Imputation of Unquantifiable Values Using Bayesian Statistics for a Mixture of Censored or Truncated Distributions: Application to Trace Elements Measured in Blood of Olive Ridley Sea Turtles from Mexico.

One recurring difficulty in ecotoxicological studies is that a substantial portion of concentrations are below the limits of detection established by analytical laboratories. This results in censored distributions in which concentrations of some samples are only known to be below a threshold. The currently available methods have several limitations because they cannot be used with complex situations (e.g., different lower and upper limits in the same dataset, mixture of distributions, truncation and censoring in a single dataset). We propose a versatile method to fit the most diverse situations using conditional likelihood and Bayesian statistics. We test the method with a fictive dataset to ensure its correct description of a known situation. Then we apply the method to a dataset comprising 25 element concentrations analyzed in the blood of nesting marine turtles. We confirm previous findings using this dataset, and we also detect an unexpected new relationship between mortality and strontium concentration.

Heavy metals detection in river water with cantilever nanobiosensor.

Heavy metals can be highly toxic depending on the dose and the chemical form. In this context, sensing devices such as nanobiosensors have been presented as a promising tool to monitor contaminants at micro and nanoscale. In this work, cantilever nanobiosensors with phosphatase alkaline were developed and applied to detect heavy metals (Pb, Ni, Cd, Zn, Co, and Al) in river water. The nanobiosensor surface was functionalized by the self-assembled monolayers (SAM) technique using 16-mercaptohexadecanoic acid, N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and N- hydroxysuccinimide (NHS), and phosphatase alkaline enzyme. The sensing layer deposited on the cantilever surface presented a uniform morphology, at nanoscale, with 80 nm of thickness. The nanobiosensor showed a detection limit in the ppb range and high sensitivity, with a stability of fifteen days. The developed cantilever nanobiosensor is a simple tool, suitable for the direct detection of contaminants in river water.

Verificación intralaboratorio de la norma iso 6579: Método horizontal para la detección de salmonella spp. en fórmula en polvo para lactantes. / Intralaboratory verification of iso 6579 standard: horizontal method for the detection of salmonella spp. in powdered infant formula

Las fórmulas en polvo para lactantes no son productos estériles, pudiendo contener microorganismos patógenos capaces de producir enfermedad severa en lactantes. La introducción de estos contaminantes puede ocurrir no sólo durante la fabricación del producto, sino también en su manipulación o almacenamiento[1]. El Código Alimentario Argentino, en su artículo 1340[2], incisos E. A1 y E. A2, establece los criterios microbiológicos aplicables a productos para lactantes que han de consumirse después de añadir un líquido para la población de 0 a 6 meses y para la población de 6 a 12 meses, en los cuales el método de referencia para la determinación de Salmonella spp. es la norma ISO 6579[3]. Al tratarse de una norma validada es importante disponer de protocolos que verifiquen su adecuada aplicación, garantizando así resultados confiables para el control de inocuidad de estos productos. Dichos protocolos pueden ser útiles para orientar a otros laboratorios en la verificación de la implementación del método en cuestión o para desarrollar un protocolo de verificación de otras normas ya validadas. En consideración de lo anterior, se desarrolló un estudio analítico de tipo experimental que permitió constatar, mediante el cálculo del límite de detección, la sensibilidad y la especificidad, que la metodología aplicada en el Laboratorio de Microbiología del Instituto Nacional de Alimentos cumple con los parámetros de rendimiento de la norma ISO 6579[3] (Método horizontal para la detección de Salmonella spp.) para la matriz fórmula en polvo para lactantes, brindando por lo tanto resultados confiables y comparables.

Powdered infant formula is not a sterile product; it may contain pathogenic microorganisms capable of producing diseases in infants. The introduction of these contaminants can occur not only during the product manufacture, but also in its handling or storage. The Argentine Food Code, in its article 1340 (subsections E.1 and E.2), establishes the microbiological criteria applicable to products for infants that are consumed after adding a liquid, for the population from 0 to 6 months and for the population of 6 to 12 months, in which the reference method for the determination of Salmonella spp. is the Standard ISO 6579. In the case of a validated standard it is important to have protocols to verify its proper application, ensuring reliable results for the control of safety of these products. These protocols may be useful to provide guidance to other laboratories in the verification of the implementation of the method in question or to develop a verification protocol to other standards already validated. In consideration of the above, an analytical study of experimental type was developed to verify, through the calculation of the detection limit, the sensitivity and the specificity, that the methodology applied in the Microbiology Laboratory of the National Institute of Food complies with the performance parameters of the ISO 6579 (horizontal method for the detection of Salmonella spp.) for powdered infant formula, providing reliable and comparable results.

Liquid chromatography with high resolution mass spectrometry for identification of organic contaminants in fish fillet: screening and quantification assessment using two scan modes for data acquisition.

This study proposed a strategy to identify and quantify 182 organic contaminants from different chemical classes, as for instance pesticides, veterinary drug and personal care products, in fish fillet using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QToF/MS). For this purpose, two different scan methods (full scan and all ions MS/MS) were evaluated to assess the best option for screening analysis in spiked fish fillet samples. In general, full scan acquisition was found to be more reliable (84%) in the automatic identification and quantification when compared to all ions MS/MS with 72% of the compounds detected. Additionally, a qualitative automatic search showed a mass accuracy error below 5ppm for 77% of the compounds in full scan mode compared to only 52% in all ions MS/MS scan. However, all ions MS/MS provides fragmentation information of the target compounds. Undoubtedly, structural information of a wide number of compounds can be obtained using high resolution mass spectrometry (HRMS), but it is necessary thoroughly assess it, in order to choose the best scan mode.

Electrochemical Study and Characterization of an Amperometric Biosensor Based on the Immobilization of Laccase in a Nanostructure of TiO2 Synthesized by the Sol-Gel Method.

Laccase amperometric biosensors were developed to detect the catechol compound. The laccase enzyme (LAC) immobilization was performed on nanostructures of (a) titania (TiO2); (b) titania/Nafion (TiO2/NAF) (both immobilized by the sol-gel method) and a third nanostructure, which consisted of a single biosensor composite of Nafion and laccase enzyme denoted as NAF/LAC. The Nafion was deposited on a graphite electrode and used to avoid "cracking" on the matrix. The TiO2 particle size was an average of 66 nm. FTIR spectroscopy vibration modes of different composites were determined. The electrochemical behavior of the biosensor was studied using electrochemical spectroscopy (EIS) and cyclic voltammetry (CV). The biosensor based on TiO2/NAF/LAC presented the best electro-chemical properties with regard to sensitivity, stability and detection limit after a period of 22 days.

New approaches for the standardization and validation of a real-time qPCR assay using TaqMan probes for quantification of yellow fever virus on clinical samples with high quality parameters.

The development and production of viral vaccines, in general, involve several steps that need the monitoring of viral load throughout the entire process. Applying a 2-step quantitative reverse transcription real time PCR assay (RT-qPCR), viral load can be measured and monitored in a few hours. In this context, the development, standardization and validation of a RT-qPCR test to quickly and efficiently quantify yellow fever virus (YFV) in all stages of vaccine production are extremely important. To serve this purpose we used a plasmid construction containing the NS5 region from 17DD YFV to generate the standard curve and to evaluate parameters such as linearity, precision and specificity against other flavivirus. Furthermore, we defined the limits of detection as 25 copies/reaction, and quantification as 100 copies/reaction for the test. To ensure the quality of the method, reference controls were established in order to avoid false negative results. The qRT-PCR technique based on the use of TaqMan probes herein standardized proved to be effective for determining yellow fever viral load both in vivo and in vitro, thus becoming a very important tool to assure the quality control for vaccine production and evaluation of viremia after vaccination or YF disease.

Detection of explosives on the surface of banknotes by Raman hyperspectral imaging and independent component analysis.

The aim of this study was to develop a methodology using Raman hyperspectral imaging and chemometric methods for identification of pre- and post-blast explosive residues on banknote surfaces. The explosives studied were of military, commercial and propellant uses. After the acquisition of the hyperspectral imaging, independent component analysis (ICA) was applied to extract the pure spectra and the distribution of the corresponding image constituents. The performance of the methodology was evaluated by the explained variance and the lack of fit of the models, by comparing the ICA recovered spectra with the reference spectra using correlation coefficients and by the presence of rotational ambiguity in the ICA solutions. The methodology was applied to forensic samples to solve an automated teller machine explosion case. Independent component analysis proved to be a suitable method of resolving curves, achieving equivalent performance with the multivariate curve resolution with alternating least squares (MCR-ALS) method. At low concentrations, MCR-ALS presents some limitations, as it did not provide the correct solution. The detection limit of the methodology presented in this study was 50 µg cm(-2).

Microscopy and microanalysis of complex nanosized strengthening precipitates in new generation commercial Al-Cu-Li alloys.

Precipitates (ppts) in new generation aluminum-lithium alloys (AA2099 and AA2199) were characterised using scanning and transmission electron microscopy and atom probe tomography. Results obtained on the following ppts are reported: Guinier-Preston zones, T1 (Al2 CuLi), ß' (Al3 Zr) and δ' (Al3 Li). The focus was placed on their composition and the presence of minor elements. X-ray energy-dispersive spectrometry in the electron microscopes and mass spectrometry in the atom probe microscope showed that T1 ppts were enriched in zinc (Zn) and magnesium up to about 1.9 and 3.5 at.%, respectively. A concentration of 2.5 at.% Zn in the δ' ppts was also measured. Unlike Li and copper, Zn in the T1 ppts could not be detected using electron energy-loss spectroscopy in the transmission electron microscope because of its too low concentration and the small sizes of these ppts. Indeed, Monte Carlo simulations of EEL spectra for the Zn L2,3 edge showed that the signal-to-noise ratio was not high enough and that the detection limit was at least 2.5 at.%, depending on the probe current. Also, the simulation of X-ray spectra confirmed that the detection limit was exceeded for the Zn Kα X-ray line because the signal-to-noise ratio was high enough in that case, which is in agreement with our observations.

Simplified protocol for DNA extraction and amplification of 2 molecular markers to detect and type Giardia duodenalis.

We evaluated the ability of 3 kits: QIAmp® DNA stool mini kit (Qiagen, Hilden, Germany), PureLink PCR Purification®, and PureLink™ Genomic DNA® (Invitrogen, Carlsbad, CA, USA) for DNA extraction, and of 2 molecular markers (heat shock protein [HSP] and ß-giardin genes) for detection and genotyping of Giardia duodenalis stool samples. The detection and typing limits of the markers were determined by the DNA concentration of trophozoites and cysts and were tested in 26 clinical samples. Of the 3 kits tested, the PureLink PCR Purification gave the best results when tested with clinical samples with low, intermediate, and high numbers of cysts. The DNA extracted from trophozoites and cysts was diluted successively in 1:2 ratios until it was no longer possible to observe the amplified product in polyacrylamide gel. Similarly, a suspension of cysts was diluted until no cysts were observed, and then the DNA was extracted. The amount of DNA of trophozoites and cysts for the typing of the parasite was smaller for the HSP marker than for ß-giardin. Combined use of both markers allowed us to detect DNA of Giardia in parasitologically positive samples in a higher percentage (75%) than the results obtained for each marker and in 1 parasitologically negative sample, indicating that this combination increased the potential to accurately detect and genotype this parasite. We also concluded that the HSP marker has a higher limit of detection and typing than the ß-giardin marker and that the DNA extraction method tested for G. duodenalis is simpler and more efficient than those that are currently in use and can be applied on a large scale.

Determinação do limite mínimo de detecção da técnica de Nested-PCR para os poliomavírus JC e BK / Assessment of minimum detection limit of Nested-PCR for JC and BK polyomaviruses

Introduction: Polyomaviruses (BKV and JCV) cause infection mainly in immunocompromised adults. A sensitive and specific diagnosis tool is fundamental to demonstrate the BKV and JCV infections. Nowadays many laboratories are using a PCR technique for detecting polyomaviruses genome in clinical samples. In this context, the purpose of this study is to determine the threshold of detection of the nested-PCR for polyomaviruses JC and BK. Methods: Serial dilutions of the samples of BKV and JCV of known concentration (100 copies/mL, 50 copies/mL, 25 copies/mL, 10 copies/mL, 5 copies/mL, and 1 copy/ml) were subjected to the technique of nested-PCR. All dilutions were tested 11 times to determine the minimum detection limit. Results: The minimum detection limit of the nested-PCR for JC and BK viruses was 25 copies/mL. This dilution (25 copies/mL) showed 100% PCR positive reaction. Furthermore, we found that weak positive results were obtained at dilutions of 1,5 and 10 copies/mL in some repetitions. Dilutions of 25, 50, and 100 copies/mL always had very positive results. Conclusions: These values are similar to those reported in other studies, contributing to the indication of this PCR for potential diagnostic purposes.

Introdução: Os poliomavírus (JCV e BKV) causam infecções principalmente em adultos imunocomprometidos. Um diagnóstico sensível e específico é de fundamental importância para os pacientes portadores de JCV e BKV. Atualmente alguns laboratórios têm utilizado a técnica de PCR para a detecção do material genético destes vírus em amostras clínicas. Assim, o objetivo deste estudo é determinar o limite mínimo de detecção da técnica de nested-PCR para os poliomavírus JC e BK. Métodos: Diluições seriadas (100 cópias/mL; 50 cópias/mL; 25 cópias/mL; 10 cópias/mL; 5 cópias/mL e 1 cópia/mL) de controles positivos comerciais de JCV e BKV com concentrações conhecidas foram submetidas à técnica de nested-PCR semi-duplex. Todas as diluições foram testadas 11 vezes para determinação do limite mínimo de detecção. Resultados: O limite mínimo de detecção da reação de nested-PCR para os vírus JC e BK foi de 25 cópias/mL para ambos, com 100% de positividade das diluições testadas na reação de PCR. Ainda, pudemos observar que resultados positivos fracos foram obtidos nas diluições de 1, 5 e 10 cópias/mL em algumas das repetições realizadas. As diluições de 25, 50 e 100 cópias/mL sempre obtiveram resultado rancamente positivo. Conclusões: Estes valores são semelhantes aos relatados em outros estudos, contribuindo para a indicação desta reação de PCR para potenciais fins diagnósticos.

Validación e implementación de una metodología para el análisis microbiológico de un producto líquido preservado, elaborado en una industria farmacéutica / Validation and implementation of a methodology for the microbiological analysis of a preserved liquid product produced in a pharmaceutical industry

Objetivo: validar e implementar una metodología para el análisis microbiológico de un producto líquido preservado con parabenos, elaborado en una industria farmacéutica, según las técnicas de análisis propuestas por la United States Pharmacopeia (USP), versión XXXIV, 2011. Métodos: para los ensayos cuantitativos se trabajó con Staphylococcus aureus y Candida albicans, y para los ensayos cualitativos con Escherichia coli, Staphylococcus aureus y Pseudomonas aeruginosa. Resultados: se obtuvieron resultados acordes con lo establecido por la USP. La metodología descrita se consideró reproducible y robusta al tener la capacidad de no ser afectada por variaciones al desarrollar la técnica, lo cual genera resultados confiables y precisos. Conclusiones: todos los parámetros de validación cumplen la especificación según la USP, lo que muestra conformidad en la totalidad de los parámetros evaluados.

Objective: to validate and to implement a methodology for microbiological analysis of a liquid product preserved with parabens produced by a pharmaceutical company, based on the United States Pharmacopeia analytical methods, XXXIV version, 2011. Methods: the quantitative tests were carrying out for Staphylococcus aureus and Candida albicans, and qualitative tests for Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Results: the results were consistent with those established by the USP. The described methodology was considered reproducible and robust because of its capacity of being unaffected by variations when implementing the technique, thus generating reliable and accurate results. Conclusions: all validation parameters met the USP specification, showing compliance with all the evaluated parameters.

Cuantificación de glibenclamida en muestras de limpieza de equipos farmacéuticos mediante cromatografía líquida de alta resolución / Quantification of glibenclamide in cleaning samples of pharmaceutical equipment through high performance liquid chromatography

Objetivo: proponer un procedimiento analítico selectivo para la cuantificación de glibenclamida en muestras de limpieza de equipos farmacéuticos mediante cromatografía líquida de alta resolución. Métodos: la fase móvil consistió en una mezcla equivalente de volúmenes de acetonitrilo y solución amortiguadora KH2PO4 de concentración 0,037 mol/L a pH 5,25 y flujo 1,5 mL/min, en una columna Nucleosil 100 C8. La glibenclamida se inyectó con progesterona como estándar interno y empleando detector UV a una l= 230 nm. Resultados: el método resultó lineal en el intervalo de concentraciones de 0,4-150 mg/mL, teniendo como límites de detección y cuantificación 10 y 40 ng/mL respectivamente y siendo específico al analito en presencia del placebo, sus productos de degradación y a otros ingredientes farmacéuticamente activos. Se consideraron potenciales de interferencias para el método propuesto: captopril, clortalidona, dexametasona, digoxina, 8-cloroteofilina, difenhidramina HCl, fenobarbital, haloperidol, hidroclorotiazida, ácido fumárico, ketotifeno, metoclopramida HCl, piridoxina HCl, piroxicam, prednisona y nifedipino. Se identificaron: ibuprofeno, indometacina, trifluoperazina HCl, tioridazina HCl e imipramina HCl, como interferentes del procedimiento en concentraciones cercanas a 10 mg/mL. Conclusiones: el método desarrollado es sensible, rápido y especialmente selectivo para la evaluación de residuales del principio activo glibenclamida en equipos de producción de tabletas, empleando un muestreo por hisopado, y pudiera utilizarse potencialmente cuando exista sospecha de contaminación cruzada de glibenclamida con otros fármacos de los aquí descritos.

Objective: to submit a selective analytical method for quantization of glibenclamide in cleaning samples of pharmaceutical equipment using high performance liquid chromatography. Methods: the mobile phase consisted of an equal mixing of acetonitrile/phosphate buffer KH2PO4; with 0.037 mol/L concentration pH 5.25 and flow of 1.5 mL/min, in a Nucleosil 100 C8 column. Glibenclamide was injected with progesterone as internal standard and using an UV detector= 230 nm Results: the method was linear in the 0.4-150 mg/mL concentration interval having a detection and quantization limits of 10 and 40 ng/mL respectively. It was specific to analyte when placebo is present, to degradation products and to other active ingredients. Possible interferences with the proposed method was considered for captopril, chlortalidone, dexametasone, diphenhydramin HCl, digoxine, 8-chlortheophylline, diphenhydramina HCl, phenobarbital, haloperidol, hydrochlorothiazide, fumaric acid, ketotifen, metoclopramide HCl, piridoxine HCl, piroxicam, prednisone and nifedipine, On the other hand, ibuprofen, indometacin, trifluoperazine HCl, thioridazine HCl and imipramine were identified as interferences in the procedure at concentration figures close to 10 mg/mL. Conclusions: the present method is sensitive, quick and selective for the evaluation of residues of active pharmaceutical principle glibenclamide in tablet production equipment after a swap sampling and it could be potentially used in case of cross-contamination of glibenclamide and other drugs already described.

Montaje y validación del método de análisis poscombustión y detección por infrarrojo no dispersivo para determinación de carbono orgánico total (cot) en agua / Assembly and validation by the method of combustion analysis and ondispersive innfrared detection for determining total organic carbon (toc) in water

La técnica de análisis por combustión y detección por infrarrojo no dispersivo (IRND) fue validada para la determinación de materia orgánica en agua, cuantificada como carbono orgánico total (COT). Previamente se optimizó la eliminación del carbono inorgánico (CI) de la muestra con un tiempo óptimo de 1,5 min y una relación ácido de 5%. Se estableció un rango dinámico lineal (RDL) entre 3 y 20 mg/L de COT, en el cual la recta de regresión cumplió con los parámetros que acreditaron su linealidad según el análisis por el método de los mínimos cuadrados, mostrando un coeficiente de correlación de 0,9994. La sensibilidad expresada por la pendiente de la recta de regresión indicó una variación de aproximadamente 5 unidades en la respuesta del detector por cada mg/L de COT. Los límites de detección y cuantificación obtenidos a partir de la recta de regresión fueron 0,517 y 1,722 mg/L de COT, respectivamente. La precisión de la técnica, teniendo como meta un 5% en coeficiente de variación (CV), fue mejor en el agua potable y en concentraciones cercanas a ésta (aprox. 7 mg/L de COT), mientras que las mayores desviaciones se presentaron en concentraciones cercanas a los límites inferior y superior del RDL. Las recuperaciones de concentraciones conocidas sobre muestras reales adicionadas fueron del 85% con baja adición y del 83% con adición alta, valores que sugieren una reevaluación del desempeño de la técnica con respecto a su exactitud, no obstante se alcanzó la meta de recuperación comprendida entre el 70 y el 130%. La técnica así establecida es por tanto apta para el análisis de aguas crudas, potables y residuales y es viable su utilización en el seguimiento a procesos de oxidación avanzada aplicados en el tratamiento de agua para consumo humano.

The technique of combustion analysis and detection by non-dispersive infrared (NDIR) was validated for the determination of organic matter in water, quantified as total organic carbon (TOC). Previously optimized the elimination of inorganic carbon (IC) of the sample with an optimum time sparge of 1.5 min and an acid ratio of 5%. It established a linear dynamic range (LDR) between 3 and 20 mg/L of TOC, in which the regression line that met the parameters credited its linearity as analyzed by the method of least squares, showing a correlation coefficient of 0,9994. The sensitivity expressed by the slope of the regression line indicated a variation of about 5 units in the detector response for each mg/L of TOC. The detection and quantification limits obtained from the regression line were 0.517 and 1.722 mg/L of TOC, respectively. The precision of the technique, aiming at 5% coefficient of variation (CV) was better in the drinking water at concentrations close to it (about 7 mg/L of TOC), whereas larger deviations were presented at concentrations near the lower and upper limits of LDR. The recoveries of known concentrations of actual samples of 85% additions were low addition and 83% with high added values that suggest a reevaluation of the performance of the technique with respect to its accuracy, however the goal was reached between recovery 70 to 130%. The technique is well established thereby capable of analyzing raw water, drinking and waste and feasible to use in monitoring advanced oxidation processes applied in the treatment of drinking water.

Estabilidad por cromatografía en capa delgada de mezclas de tinturas de Quassia amara y Maytenus ilicifolia / Stability by thin-layer chromatography from Quassia amara and Maytenus ilicifolia tinctures

Una línea de investigación que ha tomado auge en los últimos tiempos, es aquella que se refiere a los productos fitoterapéuticos, por lo que se hizo necesaria una evaluación integral para su posterior utilización. Este trabajo describe un método por cromatografía en capa delgada, para evaluar la estabilidad de tinturas obtenidas a partir de un proceso de percolación de 2 plantas de origen brasileño: Quassia amara y Maytenus ilicifolia. El estudio se realizó teniendo en cuenta 3 temperaturas de almacenamiento: refrigeración, ambiente y 40 ºC, durante un tiempo de 90 días. Se seleccionaron las condiciones cromatográficas, se determinó el límite de detección y se demostró la selectividad del método, para lo cual se sometió el extracto a 4 condiciones de estrés. Se usó como fase móvil n-butanol-acido acético-agua (4:1:5) y como revelador la luz ultravioleta a una l de 366 nm. Los mejores resultados se observan cuando el extracto analizado se conserva en refrigeración durante el tiempo de estudio. Bajo condiciones de estrés, solo existen resultados favorables cuando es expuesto a la luz ultravioleta. Se establece como límite de detección el correspondiente a 7 µL.

In past years, a research field with boom is that related to phytotherapeutical products, being necessary an integral research for its latter utilization. Present paper describes a thin layer chromatography (TLC) method to assess the stability of tinctures obtained from a percolation process of two Brazilian plants: Quassia amara and Maytenus ilicifolia. Study took into account three storage temperatures: refrigeration, room-temperature and at 40 ºC during 90 days. Chomatographic conditions were selected, detection limit was determined, and method selectivity was demonstrated where the extract undergoes four stress-conditions. As a mobile phase we used n-butanol-acetic acid-water (4:1:5), and as UV at a l of 366 nm. The better results are obtained when analyzed extract is stored in refrigeration during study-time. Under stress-conditions only it is possible to obtain favorable results under UV. Detection limit is that corresponding to 7 µL.

Determinação do limite mínimo de detecção da técnica de PCR “nested” para o vírus da hepatite B (HBV) / Evaluation of minimum detection limit to hepatitis B virus (HBV) PCR “nested”

Mundialmente, a hepatite pelo vírus B (HBV) é considerada um dos maiores problemas de saúde pública, apesar da vacinação. A Organização Mundial da Saúde (OMS) estima que mais de 2 bilhões de pessoas estejam infectadas pelo HBV. O Brasil é classificado como área de incidência intermediária pela OMS. No entanto, estudos de prevalência detectaram diferenças de índices de infecção nas regiões geográficas: 8% na região Amazônica, 2,5% nas regiões Centro-Oeste e Nordeste, 2% na Sudeste e 1% na região Sul. Um diagnóstico sensível e específico é de fundamental importância para os pacientes portadores do HBV. O objetivo deste estudo foi determinar o limite mínimo de detecção da técnica de PCR “nested” “in house” para o HBV. Diluições seriadas de uma amostra quantificada de HBV (1000 cópias/mL; 750 cópias/mL; 500 cópias/mL; 250 cópias/mL) foram submetidas à técnica de PCR “nested”. O alvo da amplificação por PCR foi a região do core e pré-core do vírus. Para extração dos ácidos nucléicos da amostra foi empregado o kit comercial QIAmp. O limite mínimo de detecção encontrado foi de 500 cópias/mL ou 10 cópias por reação de PCR.

All over the world, the hepatitis B virus (HBV) is considered one of the major problems of public health, despite vaccination. World Health Organization (WHO) estimates that more than 2 billions of persons are infected by HBV. Brazil is classified as an area of intermediary incidence by WHO. However, prevalence studies have detected differences of infection indexes in geographic regions: 8% in the Amazonian region, 2,5% in middle-west and Northeast, 2% in Southeast and 1% in South. A sensitive and specific diagnosis is very important to the HBV carrier patients. The aim of this study was to determine the minimum limit of detection of the nested PCR in house technique for HBV. Serial dilutions of one quantified sample of HBV (1000 copies/mL; 750 copies/mL; 500 copies/mL; 250 copies/mL) were submitted to a nested PCR. The target of PCR was viral core and pre-core region. Commercial kit, QiAmp, was employed to purify nucleic acids from the sample. The minimum detection limit found was 500 copies/mL or 10 copies per PCR reaction.

Detection of anorexigen and benzodiazepinic drugs in weigth reducers compounded formulations and analysis on label contents adequacy by Pharmacognosy Laboratory - Instituto Adolfo Lutz, from June 2004 to March 2007 / Pesquisa de anorexígenos e benzodiazepínicos em formulações emagrecedoras e avaliação de rotulagem, em análises da Seção de Farmacognosia do Instituto Adolfo Lutz no período de junho de 2004 a março de 2007

Obesity has turned to be an important public health issue in Brazil. Nowadays, there are many products so called weight reducer compounded pharmaceuticals claiming effectiveness as weight reducers. From June 2004 to March 2007, the Pharmacognosy Laboratory of Instituto Adolfo Lutz analyzed 22 samples of compounded pharmaceuticals formulations in order to identify anorexigenic drugs (diethylpropione, fenproporex, mazindol and benzodiazepinic) drugs: (chlordiazepoxide, clonazepam, diazepam, bromazepam and lorazepam). The analysis was carried out using comparative thin layer chromatography technique. The label contents were also evaluated in accordance with Brazilian legislation. Detection limit was established to each analyzed compound in accordance with the respective reference standards. Although compound combination of anorexigen, benzodiazepinic and laxative agents are forbidden by Brazilian laws, three out 22 samples were positive for diethylpropione or diazepam with fenproporex. In addition, these substances were not mentioned in the label content. Sixteen samples were in disagreement regarding to the labeling requirements for omitting essential information. These findings showed that much concerns have to be taken by the rule authorities on these compounded pharmaceuticals in order to avoid harmful misuse.

A obesidade tem se tornando significante problema de saúde pública no Brasil. Atualmente, os produtos denominados fórmulas emagrecedoras são encontrados em profusão no mercado, com o argumento de promover redução de peso corpóreo. No período de junho de 2004 a março de 2007, foram efetuadas na Seção de Farmacognosia do Instituto Adolfo Lutz Central/ SP análises de 22 amostras de fórmulas para pesquisar a presença de anorexígenos (dietilpropiona, femproporex, mazindol) e benzodiazepínicos (clordiazepóxido, clonazepam, diazepam, bromazepam, lorazepam). Foi empregada a cromatografia em camada delgada comparativa frente aos respectivos padrões; a avaliação de conformidade da rotulagem foi realizada seguindo-se a legislação vigente. Os limites de detecção foram determinados para cada fármaco pesquisado, com os padrões utilizados na respectiva técnica de cromatografia. Três amostras apresentaram dietilpropiona ou diazepam com femproporex, as quais não estavam declaradas nos seus rótulos e nos rótulos de todas as amostras analisadas houve a menção da presença de substâncias laxantes. Das amostras analisadas, 16 estavam em desacordo com a legislação específica vigente quanto aos dizeres de rótulo. A associação de anorexígenos com benzodiazepínicos e laxantes, embora proibida pela legislação brasileira, é ainda encontrada nos produtos comercializados, constituindo-se importante risco