This study involved an animal experiment in which testosterone propionate was intramuscularly injected into four steers, and the ensuing urine samples were analyzed using high-performance liquid chromatography-tandem mass spectrometry. The enzymatic hydrolysis conditions were analyzed using analysis of variance (ANOVA) and response surface methodology employing a 33 Box-Behnken design. A survey study was performed in which 48 urine samples were collected from eight untreated steers to estimate the endogenous levels of testosterone metabolites, and it was found that 17β-testosterone was not detected in the majority of the samples, whereas 17α-testosterone was present in 43 of the 48. Drug abuse was identified within 11 days of 17β-testosterone administration. The ratio between both isomers was also assessed; however, a cut-off limit based on an untreated population could not be estimated due to the absence of the beta isomer. Therefore, there may be a correlation between the exogenous use of testosterone in castrate animals and high levels of 17β-testosterone, although confirmation through further investigation would be required.

This work involved the validation of a multiresidue method according to the Normative Instruction 24/2009-MAPA for determining 25 analytes, among fluoroquinolones, sulfonamides and trimethoprim in samples of poultry and porcine kidney. The extraction procedure was based on a QuEChERS approach. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed using the selected reaction monitoring mode (SRM) and ESI+ ionization. All of the validated figures of merit were evaluated as satisfactory. Accuracy was assessed by recovery studies, varying from 82.7 to 115.5% for porcine kidney and from 91.5 to 110.4% for poultry kidney. Relative standard deviations were lower than 25.5% for porcine kidney, and 29.8% for poultry kidney. Decision limits (CCα) comprised values from 10.37 to 3298.43 µg kg-1 for porcine kidney and 10.08 to 3176.59 µg kg-1 for poultry kidney. Detection capabilities (CCβ) varied from 10.73 to 3396.86 µg kg-1 for porcine kidney and 10.67 to 3253.19 µg kg-1 for poultry kidney. The developed method has been successfully employed in the routine analysis of incurred samples.

This work presents an optimization of a quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction approach of eleven fluoroquinolones in poultry muscle and kidney using a 33 Box-Behnken factorial design. All the data treatment was performed using Microsoft Excel® 2010. The suitability of the developed method was confirmed by two proficiency tests for ciprofloxacin and enrofloxacin.

Um método alternativo para determinação de etambutol (ETB) por espectrofotometria UV em formulações farmacêuticas por complexação com Cu(II) foi otimizado usando um planejamento fatorial completo 3², tendo como variáveis Cu(II) e tampão aquoso de acetato de sódio em pH 4,6. A estequiometria predominante do complexo em solução aquosa tamponada nesse pH e a constante de formação do complexo foram obtidas usando o método de Job e o diagrama de Scatchard, respectivamente. A estrutura cristalina do complexo de monocristal foi obtida por difração de raios X. O método espectrofotométrico foi aplicado na análise de formulação farmacêutica sendo encontrado: 408,0 ± 11,9 mg de ETB·2HCl, faixa de recuperação de 100,9-104,0% e limites de detecção e quantificação de 0,8 e 2,8 mg L-1, respectivamente. O método espectrofotométrico ao ser comparado com o método por eletroforese capilar de zona não evidenciou diferenças significativas no intervalo de 95% de confiança

An alternative method for ethambutol (ETB) determination by UV spectrophotometry in pharmaceutical formulations using ETB complexation with Cu(II) was optimized employing a 3² full experimental design having Cu(II) and aqueous acetic acid/sodium acetate buffer at pH 4.6 as variables. The predominant complex stoichiometry in aqueous buffer solution at this pH and formation constant were obtained by using Job's method and Scatchard diagram, respectively. The complex crystalline structure of monocrystal was obtained by X-ray diffraction. The developed method was applied to the pharmaceutical formulation analysis being found: 408.0 ± 11.9 mg of ETB·2HCl, recovery range of 100.9-104.0% and detection and quantification limits of 0.8 and 2.8 mg L-1, respectively. The spectrophotometric method was compared to zone capillary electrophoresis and no significant difference was found within the 95% confidence interval

Um método alternativo por eletroforese capilar de zona (CZE) para determinação de ciprofloxacina (CPFLX), gatifloxacina (GTFLX), moxifloxacina (MFLX) e ofloxacina (OFLX) foi validado. O sistema de eletrólito utilizado consistiu da mistura de 25 mmol L-1 de TRIS/ HCl e 15 mmol L-1 de tetraborato de sódio em meio aquoso resultando em pH 8,87. A análise foi realizada sob detecção direta por UV em 282 nm com tempo de análise de 3 min. Os parâmetros analíticos de validação avaliados foram: linearidade (r > 0,998), seletividade (comparação entre a inclinação da curva de calibração de padronização externa e curva de calibração de adição de padrão), repetitividade em área para amostras (RSD %: < 3,94% para CPFLX, < 3,87% para GTFLX, 1,30% para MFLX e < 1,88% para OFLX), precisão intermediária em área para amostras (RSD%: < 3,59% para CPFLX, < 3,09% para GTFLX, 2,67% para MFLX e < 2,25% para OFLX), exatidão (média da faixa de recuperação: 101,2% para CPFLX, 101,0% para GTFLX, 101,3% para MFLX e 99,9% para OFLX), limite de detecção (mg L-1: 2,72 para CPFLX, 1,92 para GTFLX, 0,795 para MFLX e 1,05 para OFLX), limite de quantificação (mg L-1: 9,06 para CPFLX, 6,40 para GTFLX, 2,65 para MFLX e 3,50 para OFLX) e robustez. Devido à simplicidade, seletividade, precisão, exatidão e rapidez, o método pode ser uma alternativa interessante para auxiliar o controle da qualidade dessas drogas na indústria farmacêutica.

An alternative capillary zone electrophoresis (CZE) method for the determination of ciprofloxacin (CPFLX), gatifloxacin (GTFLX), moxifloxacin (MFLX) and ofloxacin (OFLX) through a simple aqueous electrolyte system consisting of 25 mmol L-1 of TRIS/ hydrochloride and 15 mmol L-1 of sodium tetraborate buffer mixture (pH 8.87) using direct UV detection at 282 nm within 3 min was validated. The analytical parameters of validation evaluated were: linearity (r > 0.998), selectivity (comparison between slope of the calibration curve of external standard and calibration curve of standard addition), repeatability in area for sample (RSD%: < 3.94% for CPFLX, < 3.87% for GTFLX, 1.30% for MFLX and < 1.88% for OFLX), intermediate precision in area for sample (RSD%: < 3.59% for CPFLX, < 3.09% for GTFLX, 2.67% for MFLX and < 2.25% for OFLX), accuracy (mean of recovery range: 101.2% for CPFLX, 101.0% for GTFLX, 101.3% for MFLX and 99.9% for OFLX), limit of detection (mg L-1: 2.72 for CPFLX, 1.92 for GTFLX, 0.795 for MFLX and 1.05 for OFLX), limit of quantification (mg L-1: 9.06 for CPFLX, 6.40 for GTFLX, 2.65 for MFLX and 3.50 for OFLX) and robustness. Due to its simplicity, selectivity, precision, accuracy and rapidity, the methodology can be an interesting alternative for quality assurance in the pharmaceutical industry of these drugs.

Uma metodologia alternativa por eletroforese capilar de zona (ECZ) é proposta para a análise de losartan potássio (LOS) associado com clortalidona (CTD) ou hidroclorotiazida (HCT) em cápsulas, usando 50 mmol L-1 de tampão carbonato de sódio com detecção em 226 nm. O sistema de eletrólito foi otimizado, levando em consideração o perfil do pico, resolução, tempo de análise, estabilidade da linha base e repetibilidade (ausência de adsorção). O método foi aplicado com sucesso na análise de formulações farmacêuticas adquiridas em farmácias de manipulação. Os analitos apresentaram boa separação na linha base em menos de 5 min. Os resultados obtidos não apresentaram diferença signicativa no intervalo de 95% de confiança em relação ao valor de referência. O método pode ser aplicado para a análise destes compostos ou empregado em outros formulações framacêuticas similares contendo estas drogas.

An alternative methodology by capillary zone electrophoresis (CZE) is proposed for the determination of losartan potassium (LOS) associated with chlorthalidone (CTD) or hydrochlorothiazide (HCT) in capsules, using 50 mmol L-1 of sodium carbonate buffer with detection at 226 nm. The electrolyte system was optimized, taking into account peak profiles, resolution, run times, baseline stability and repeatability (adsorption absence). The method was successfully applied to the analysis of pharmaceutical formulations purchased in manipulation drugstores. The analytes were baseline separated in less than 5 min. The results did not present significant difference in the 95% confidence interval in relation to the label claim values. The method can be applied to analyze these compounds and could also be employed in other similar formulated products containing these drugs.