Determinação de 2,5-hexanodiona em urina empregando cromatografia líquida de alta eficiência, após derivatização com 2,4-dinitrofenil-hidrazina

A method for quantifying urinary 2,5-hexanedione was optimized and validated. Urine samples were hydrolyzed and derivatized with 2,4-dinitrophenylhydrazine. The analyte was separated in a high performance liquid chromatography system with a diode array detector, using a C18 column (150 x 4.6 mm, p.d. 5 µm) and a mobile phase composed of phosphate buffer pH 2.3:acetonitrile (40:60, v/v), at a flow rate of 1 mL/min. The chromatograms were monitored at 334 nm. Retention time was 7.3 minutes. Main validation parameters were: coefficient of determination: 0.9994, accuracy: 96 to 107%; intra-assay precision (RSD): 3.08 to 6.72%; inter-assay precision (RSD): 2.54 to 8.17% and limit of quantitation of 0.19 µg/mL.

Otimização de método para análise de folatos em hortaliças folhosas por cromatografia líquida de alta eficiência com detecção por fluorescência

We optimized a method for the determination of three main folate isoforms in leafy vegetables. Analysis was carried out by HPLC, using gradient of elution and fluorescence detection. Limits of quantification were 2 ng/mL; 2 ng/mL and 28 ng/mL for tetrahydrofolate (THF), 5-methyltetrahydrofolate (5-MTHF) and 5-formyltetrahydrofolate (5-FTHF), respectively. Recovery rates of THF, 5-MTHF and 5-FTHF varied from 87.86 to 100.64%; 88.12-94.22% and 89.82-106.69%, respectively. Test of repeatability showed relative standard deviation for peak areas lower than 10%. Tests for linearity showed high coefficients of determination. The results showed advances in folates extraction and analysis in raw and cooked leafy vegetables.

Aplicações de cromatografia líquida de alta eficiência para o estudo de poluentes orgânicos emergentes

Emerging organic pollutants (EOP) include many environmental contaminants based on commercial products such as pharmaceuticals, personal care products, detergents, gasoline, polymers, etc. EOP may be candidates for future regulation as they offer potential risk to environmental and human health due to their continual entrance into the environment and to the fact that even the most modern wastewater treatment plants are not able to totally transform / remove these compounds. High performance liquid chromatography is recommended to separate emerging organic pollutants with characteristics of high polarity and low volatility, especially pharmaceuticals, from environmental matrices.

Separação semipreparativa de α e β-amirina por cromatografia líquida de alta eficiência

The resin obtained from species of the genus Protium (Burseraceae) is formed mostly of pentacyclic triterpenes: α-amyrin and β-amyrin. The separation and purification of these triterpenes were optimized in three steps.

Otimização e validação de método multirresíduo para determinação de sulfonamidas em camarão cultivado por cromatografia líquida de alta eficiência com detecção por UV

This work reports the optimization and method validation for sulfonamides (sulfamethazine, sulfaquinoxaline, sulfadimethoxine and sulfathiazole) in shrimp muscle using HPLC-UV. The sulfonamides were extracted with acetonitrile and acetic acid, and the extract cleaned up with a Strata SCX SPE cartridge prior to analysis. The method presented linearity in the range of 20-120 µg kg-1, good linear correlation (r > 0.99), and limits of quantification in the range of 4.7-20.2 µg kg-1. The recovery for shrimp muscles spiked with 50-150 µg kg-1 ranged from 63.2-108.0%. Precision and accuracy analysis showed acceptable relative standard deviation. Commercial shrimps were analyzed and sulfonamides don't were found above of the method limit of quantification.

Validação de método analítico por cromatografia líquida de alta eficiência para doseamento do adapaleno em suspensões de nanocápsulas

Adapalene is a retinoid drug often used for disorders of the skin, mainly acne. In this work, an analytical method for the quantification of adapaleno in suspensions of nanocapsules by HPLC was developed and validated. The method was linear in the range of 10-30 µg mL-1, with a good correlation coefficient (r = 0.994). Precision and accuracy analysis showed low relative standard deviation (< 4.6%) and a good recovery percentual (98.2-106.9%). The procedure was specific, linear, precise, exact and robust so that the method can be applied in quantification of adapalene in suspensions of nanocapsules.

Integração das técnicas de triagem virtual e triagem biológica automatizada em alta escala: oportunidades e desafios em P&D de fármacos

High-throughput screening (HTS) and virtual screening (VS) are useful methods employed in drug discovery, allowing the identification of promising hits for lead optimization. The efficiency of these approaches depends on a number of factors, such as the organization of high quality databases of compounds and the parameterization of essential components of the screen process. This brief review presents the basic principles of the HTS and VS methods, as well as a perspective of the utility and integration of these drug design approaches, highlighting current opportunities and future challenges in medicinal chemistry.

Desenvolvimento e validação de método analítico para quantificação do fármaco bevacizumabe por cromatografia a líquido de alta eficiência

In this study, an analytical method was developed and validated for quantitation of the drug bevacizumab (Avastin®) by high performance liquid chromatography (HPLC). The HPLC column was a BioSuite 250® HR SEC, 300 x 7.8 mm x 5 µm (Waters, USA). The mobile phase consisted of phosphate buffered saline (PBS). The results revealed that the method was specific, precise, accurate, robust and linear (r² = 0.998) from 5 to 75 µg mL-1. Therefore, this method can be used in drug release studies or in quality control ampoules of the drug.

Desenvolvimento e validação de método analítico para a determinação de sulfassalazina em suspensão oral: comparação do método espectrofotométrico e de cromatografia líquida de alta eficiência (CLAE)

Sulfasalazine is a prodrug used in the treatment of the Chron's disease and rheumatoid arthritis. Two analytical methods for analysis of sulfasalazine in oral suspension were validated using Spectrophotometric and HPLC. There is not any pharmacopoeic method to assay sulfasalazine in oral suspension. The methods are insurance and fast execution for the quality control. Both, suspension and tablets 500 mg (Azulfin®) had been analyzed by methods using UV/VIS and HPLC and the results were satisfactory.

Quantificação dos isômeros ácido L-ascórbico e ácido D-iso-ascórbico em geleias de frutas por cromatografia líquida de alta eficiência

Ascorbic acid has important nutritional characteristics such as high antioxidant potential, preventing diverse damage and diseases in the tissues and the process of aging. Different isomeric forms of the ascorbic acid can be found in nature and each one have different potential antioxidant and different activity pro-vitamin C. This work examined a method to detect and quantify the isomers L-ascorbic acid (LAA) and D-iso-ascorbic acid (DIAA) in jelly fruit. The method showed acceptable selectivity, linearity, repeatability and recovery. DIAA was not found in the analyzed samples, but LAA was found up to 605 mg in 100 g of sample.

Desenvolvimento e validação de método para o doseamento de tibolona em cápsulas por cromatografia líquida de alta eficiência

Tibolone is a synthetic steroid used for prevention of bone loss and treatment of menopause symptoms. This article describes the development and validation of an analytical method to quantify tibolone in capsules using high performance liquid chromatography with UV detection. After chromatography conditions are established the validation parameters evaluated were specificity, linearity, precision, accuracy, detection and quantification limits and robustness. The method developed is effective to analyze tibolone in capsules, being able to be used in quality control laboratory routine.

Determinação de bussulfano em plasma através de cromatografia líquida de alta eficiência com detector de arranjo de diodos e derivatização com dietilditiocarbamato de sódio

A high performance liquid chromatographic-diode array detection method for the determination of busulfan in plasma was developed and validated. Sample preparation consisted of protein precipitation followed by derivatization with sodium diethyldithiocarbamate and liquid-liquid extraction with methyl-tert-butyl ether. Chromatograms were monitored at 277 nm. Separation was carried out on a Lichrospher RP 18 column (5 µm, 250 x 4 mm). The mobile phase consisted of water and acetonitrile (20:80, v/v). The method presented adequate specificity, linearity, precision and accuracy and allowed reliable determination of busulfan in clinical plasma samples, being applied to three patients submitted to bone marrow transplantation.

Análise de agrotóxicos em água usando extração líquido-líquido com partição em baixa temperatura por cromatografia líquida de alta eficiência

This study optimized and validated the liquid-liquid extraction technique with partition at low temperature (LLE-PLT) for identification and quantification of four pesticides (chlorpyrifos, λ-cyhalothrin, permethrin, bifenthrin) in water samples. Analyses were performed by HPLC-UV. The technique was efficient for pesticide recovery with extraction exceeding 86%. Chromatographic response was linear for the four compounds in the 10-45 µg L-1 range, with correlation coefficients greater than 0.99. Limits of detection and quantitation were less than 3.5 µg L-1 and equal to 10 µg L-1, respectively. The proposed method was applied to 29 water samples from the Jaíba Project in northern Minas Gerais.

Validação de método analítico livre de acetonitrila para análise de microcistinas por cromatografia líquida de alta eficiência

Blooms of cyanobacteria represent a public health risk due to their cyanotoxins such as microcystins. Liquid chromatography techniques to separate and quantify microcystins invariably use acetonitrile as the organic component of the mobile phase. The price and availability of acetonitrile together with its elevated toxicity encourage the validation of acetonitrile-free methods of microcystin analysis. In this work, methanol was employed as the organic solvent of the mobile phase and the validation method was performed with different environmental water samples. The method showed limits of detection between 0.17 and 0.25 µg/L and of quantification between 0.55 and 0.82 µg/L for the microcystin variants: -RR, -YR, -LR, -LA.

Validação de um método para determinação simultânea de quatro ácidos orgânicos por cromatografia líquida de alta eficiência em polpas de frutas congeladas

Validation of a rapid method for the determination of ascorbic, citric, fumaric and tartaric acids in stored pulp fruit and its application as a quality parameter was performed. The validation parameters showed that for the four evaluated acids, the method presented low limits of detection (LOD) and quantification (LOQ), indicating good precision and accuracy, thus representing an important tool for quality assessment of stored fruit pulp. The results showed that the concentration of organic acids generally decreased with longer storage time in the fruit pulp under study. Amongst all the organic acids under investigation, ascorbic proved the least stable.