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 espectrofotometria UV para sistema emulsionado lipídico contendo benznidazol

A validation study of an UV spectrophotometric method was conducted for quantitative analysis of benznidazol (BZN) in a lipid. The analytical determinations were performed at 315 nm at 25 ºC. The emulsion components did not interfere on drug analyses, demonstrating the specificity of the methodology. A good linearity (r = 0.99995) and precision (RSD < 5.0%) for intra and inter-day studies, including the reproducibility test were observed. The accuracy ranged of 102.1 + 2.8 e 103.8 + 1.7%. The statistical analysis demonstrates a linear, precise, accurate and robust method for BZN quantification from the lipid emulsion system.

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.

Validação de método e determinação espectrométrica dos flavonoides das folhas e do vinhoto da cana-de-açúcar e comparação com método CLAE-UV

This paper reports on a modification of the procedures originally described in the French Pharmacopoeia for the UV-visible spectrometric analysis of flavonoids, and proposes a validation of the method and its application in the determination of total flavonoids from sugarcane (Saccharum officinarum) leaves and vinasse. An analysis of precision and accuracy revealed a low relative standard deviation (< 5.0%) and a good recovery percentages (99.79 and 98.34%). A comparison of the spectrometric results against those obtained by high performance liquid chromatography (HPLC-UV) demonstrated complete compatibility between the modified French Pharmacopoeia (spectrometric) and HPLC-UV methods

Determinação da constante de dissociação (Ka) do captopril e da nimesulida: experimentos de química analítica para o curso de farmácia

This paper presents the determination of the dissociation constant (Ka) of captopril and nimesulide as contextualized experiments to teach chemical concepts to students of Pharmacy. Captopril is an antihypertensive drug, which presents high water-solubility and weak acid properties. The pKa of carboxylic acid group of captopril is 3.7. Nimesulide is a non-steroidal anti-inflammatory drug sparingly soluble in water. It is weakly acidic (pKa ≈ 6.5) because of its methanesulfonamide functional group. The pKa of captopril was determined by potentiometric titration with NaOH 2.0 x 10-2 moL L ¹. The pKa of nimesulide was determined by using spectrophotometry and photometric titration. The experimental values of pKa of both drugs are in very good agreement with those from literature

Validação de método multirresíduo para determinação de pesticidas em alimentos empregando QuEChERS E UPLC-MS/MS

This paper presents a practical and rapid method which was validated for simultaneous quantification and confirmation of 29 pesticides in fruits and vegetables using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted following the method known as QuEChERS. Using the developed chromatographic conditions, the pesticides can be separated in less than 9 min. Two multiple reaction monitoring (MRM) assays were used for each pesticide. Four representative matrices (lettuce, tomato, apple and grapes) were selected to investigate the effect in recoveries and precision. Typical recoveries ranged from 70-120%, with relative standard deviation (RSDs) lower than 20%.

Desenvolvimento e validação de método analítico por CLAE para a quantificação simultânea de dipropionato de betametasona e fosfato sódico de betametasona em suspensão injetável

A reversed-phase HPLC method was developed and validated to separate and simultaneously quantify the association of betamethasone sodium phosphate (BP) and betamethasone dipropionate (BD) in injectable suspensions. Chromatographic conditions were ternary gradient elution at 1.6 mL/min on a C18 column with 254 nm. The linearity of the method was established in the range 120 to 280 mg/mL BD, and 48 to 112 mg/mL BP. The RSD of intermediate precision of the method was <1% and recoveries were 99-101% for both drugs. The method proved selective, linear, precise, accurate and robust for quantifying BP and BD in commercial injectable suspensions.

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.

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.

Desenvolvimento e validação de um método analítico por CLAE para quantificação de ácido ursólico em dispersões sólidas

Ursolic acid is a natural molecule that presents several pharmacological properties. In this work, an analytical method by RP-HPLC has been developed and validated for quantification of this drug in the solid dispersions, using PEG 6000 and Poloxamer 407 as polymers. The method was specific, linear in the range of 1.0-50.0 µg mL-1 (r<0.99), precise (CV < 5% for both inter- and intra-assays), accurate (maximum deviation of ± 13%), and robust to the parameters evaluated. This method has proved to be simple and useful for ursolic acid determination in solid dispersions, enabling its determination in pharmaceutical dosage form.

Desenvolvimento e validação de métodos analíticos para determinação de ácido glicirrízico, ácido salicílico e cafeína em nanopartículas de quitosana e alginato

The present work consists of the development and validation of analytical method for evaluation of glycyrrhizic acid, salicylic acid, and caffeine in chitosan-alginate nanoparticles by high performance liquid chromatography. Method validation investigated parameters such as linearity, precision, accuracy, robustness and specificity, which gave results within the acceptable range. The methods were applied to nanoparticles suspensions containing the drugs and were able to determine the entrapment efficiency successfully. The best entrapment efficiency was achieved with the glycyrrhizic acid (95.4%).

Fatores químicos e físicos que afetam a contaminação por chumbo e cobre em água potável: uma abordagem para o estudo de caso em química analítica

Lead and copper concentrations in drinking water increase considerably on going from municipality reservoirs to the households sampled in Ribeirão Preto (SP-Brazil). Flushing of only 3 liters of water reduced metal concentrations by more than 50%. Relatively small changes in water pH rapidly affected corrosion processes in lead pipes, while water hardness appeared to have a long-term effect. This approach aims to encourage University teachers to use its content as a case study in disciplines of Instrumental Analytical Chemistry and consequently increase knowledge about drinking water contamination in locations where no public monitoring of trace metals is in place.

Desenvolvimento e validação de método espectrofotométrico para determinação de corante à base de luteína adicionado em iogurte desnatado

A simple analytical method for extraction and quantification of lutein colorant added to yogurt was developed and validated. The method allowed complete extraction of carotenoids using tetrahydrofuran in vortex, followed by centrifugation, partition to diethyl ether/petroleum ether, and drying. The carotenoids dissolved in ethanol were quantified by UV-Vis spectrophotometry. This method showed linearity in the range tested (1.41-13.42 µg g-1), limits of detection and quantification of 0.42 and 1.28 µg g-1, respectively, low relative standard deviation (3.4%) and recovery ranging from 95 to 103%. The method proved reliable for quantification of lutein added to yogurt.

Desenvolvimento e validação do método QuEChERS na determinação de resíduos de medicamentos veterinários em leite e carne de búfalo

Analytical methods were developed and validated to determine residues of veterinary drugs in buffalo milk and meat, using the QuEChERS method and gas chromatography-mass spectrometry. Both milk and meat, at 2 g of sample, 4 mL of acetonitrile, 0.8 g of MgSO4 and 0.2 g of NaCl, were used in the liquid-liquid partition, whereas 50 mg of C18, 50 mg of PSA and 150 mg of MgSO4 were employed in the dispersive solid-phase extraction (d-SPE). The methods showed sensitivity, precision and accuracy. The quantitation limits were in agreement with the maximum residue limit established by the Codex Alimentarius, FAO and WHO.