Microextraction by packed sorbent and high-performance liquid chromatography for determination of benznidazole in human plasma.

Benznidazole is the main drug used in Chagas disease and its determination in plasma samples is useful in several situations. Hence, robust and accurate bioanalytical methods are needed. In this context, sample preparation deserves special attention, as it is the most error-prone, labor-intensive and time-consuming step. Microextraction by packed sorbent (MEPS) is a miniaturized technique, developed to minimize the use of hazardous solvents and sample amount. In this context, this study aimed to develop and validate a MEPS coupled to high performance liquid chromatography method for the analysis of benznidazole in human plasma. MEPS optimization was performed by a 24 full factorial experimental design, which resulted in about 25 % of recovery. The best condition was achieved when 500 µL of plasma,10 draw-eject cycles, sample volume drawn of 100 µL, and desorption with three times of 50 µL of acetonitrile were used. The chromatographic separation was performed with a C18 (150 × 4.5 mm, 5 µm) column. The mobile phase was composed of water:acetonitrile (60:40) at a flow rate of 1.0 mL min-1. The developed method was validated and proved to be selective, precise, accurate, robust and linear in the range from 0.5 to 6.0 µg mL-1. The method was applied to three healthy volunteers that made use of benznidazole tablets and showed to be adequate to assess this drug in plasma samples.

Boron nitride nanotubes for extraction of angiotensin receptor blockers from human plasma.

The limitations of silica-based sorbents boosted the development of new extraction phases. In this study, boron nitride nanotubes functionalized with octadecyl groups were used for the first time as sorbent for extraction of losartan and valsartan, the most used angiotensin receptor blockers in the clinical practice, from human plasma. The nanotubes were synthesized using the chemical vapor deposition technique, purified by acid treatment, functionalized with octadecylamine in a microwave reactor, and characterized by different techniques. The functionalized nanotubes were packed in solid phase extraction cartridges. Extraction conditions were optimized by means of a 23 factorial design with center points. The separation was performed on a biphenyl core-shell (100 × 4.6 mm; 2.6 µm) column, using 0.1 % (v/v) triethylamine solution and methanol (pH 3.2) as mobile phase, at 0.7 mL/min, in gradient elution. The injection volume was 10 µL and fluorescence detection was performed at excitation and emission wavelengths of 250 and 375 nm, respectively. The developed method was validated according to Brazilian Health Regulatory Agency (ANVISA), United States Food and Drug Administration (US FDA) and European Medicines Agency (EMA) guidelines and presented selectivity, precision, accuracy, and linearity in the concentration ranges of 50-1200 ng/mL for losartan and 20-1700 ng/mL for valsartan. Recoveries higher than 80 % were obtained. The method was fit for the quantification of losartan in plasma samples from patients under antihypertensive therapy, being useful in therapeutic drug monitoring, pharmacokinetics and bioequivalence studies.

Primary cutaneous histoplasmosis difficult to treat in immunocompetent patient: case report and literature review.

Histoplasmosis is an infection caused by the dimorphic fungus Histoplasma capsulatum. The disease is endemic in several regions of tropical and temperate climate. The fungus presents opportunistic behavior, causing widespread infection in immunocompromised patients, resulting from complication of primary pulmonary infection, due to exogenous reinfection or reactivation of a quiescent source. In immunocompetent individuals, approximately 95% of pulmonary infections are asymptomatic. However, prolonged exposure to high amount spores may lead to acute or chronic lung infection. Due to the low amount of inoculum, primary cutaneous histoplasmosis caused by traumatic implantation is extremely rare and effectively treated with triazoles. Thus, the present study aims to report a case of primary cutaneous histoplasmosis that is difficult to treat in an immunocompetent patient, and to review the literature on the incidence of drug-resistant Histoplasma capsulatum strains in clinical practice.

Primary cutaneous histoplasmosis difficult to treat in immunocompetent patient: case report and literature review / Histoplasmose cutânea primária de difícil tratamento em paciente imunocompetente: relato de caso e revisão da literatura

ABSTRACT Histoplasmosis is an infection caused by the dimorphic fungus Histoplasma capsulatum. The disease is endemic in several regions of tropical and temperate climate. The fungus presents opportunistic behavior, causing widespread infection in immunocompromised patients, resulting from complication of primary pulmonary infection, due to exogenous reinfection or reactivation of a quiescent source. In immunocompetent individuals, approximately 95% of pulmonary infections are asymptomatic. However, prolonged exposure to high amount spores may lead to acute or chronic lung infection. Due to the low amount of inoculum, primary cutaneous histoplasmosis caused by traumatic implantation is extremely rare and effectively treated with triazoles. Thus, the present study aims to report a case of primary cutaneous histoplasmosis that is difficult to treat in an immunocompetent patient, and to review the literature on the incidence of drug-resistant Histoplasma capsulatum strains in clinical practice.

RESUMO A histoplasmose é uma infecção causada pelo fungo dimórfico Histoplasma capsulatum. A doença é endêmica em diversas regiões de clima tropical e temperado. O fungo apresenta comportamento oportunístico, causando infecção disseminada em pacientes imunocomprometidos, resultante da complicação da infecção pulmonar primária, por reinfecção exógena ou reativação de um foco quiescente. Em indivíduos imunocompetentes, cerca de 95% das infecções pulmonares são assintomáticas. No entanto, a exposição prolongada à quantidade elevada de esporos pode levar à infecção pulmonar aguda ou crônica. Devido à baixa quantidade de inóculo, a histoplasmose cutânea primária causada por implantação traumática é extremamente rara e efetivamente tratada com triazóis. Assim, o presente estudo tem como objetivos relatar um caso de histoplasmose cutânea primária de difícil tratamento em paciente imunocompetente, e revisar a literatura a respeito da incidência de cepas de Histoplasma capsulatum resistentes aos fármacos utilizados na prática clínica.