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A new LC method for tizanidine hydrochloride in tablet dosage form using a charged aerosol detector (CAD) is described. The influence of various parameters on chromatographic system was investigated by factorial designs and Derringer's desirability. Chromatographic conditions were: mobile phase constituted of acetonitrile and ammonium acetate buffer 17 mM (60:40; v/v), column oven at 39 °C and flow rate 0.8 mL.min-1 performed in on Acclaim Trinity P1 column UV at 230 nm. Thus, it was possible to validate a simple method to assay the tizanidine and its counter-ion in three formulations (drug reference, generic and manipulated). Method showed specificity when challenged by forced degradation and excipients. Finally, the method was compared with USP monograph method demonstrating equivalence in assay evaluation.

Two new stability-indicating liquid chromatographic methods using two detectors, an ultraviolet (UV) and a charged aerosol detector (CAD) simultaneously connected in series were validated for the assessment of lisdexamfetamine dimesylate (LDX) in capsule. The method was optimized and the influence of individual parameters on UV and CAD response and sensitivity was studied. Chromatography was performed on a Zorbax CN column (250 mm × 4.6 mm, 5 μm) in an isocratic elution mode, using acetonitrile and 20 mM ammonium formate at pH 4.0 (50:50, v/v) as mobile phase and UV detection at 207 nm. The developed method was validated according to ICH guidelines and the parameters’ specificity, limit of detection, limit of quantitation, linearity, accuracy, precision and robustness were evaluated. CAD is designated to be a non-linear detector in a wide dynamic range, however, the method was linear over the concentration range of 70–130 μg mL−1 in both detectors. The method was precise and accurate. Robustness study was performed by a Plackett–Burman design, delivering results within the acceptable range. Neither the excipients nor the degradation products showed interference in the method after studies of specificity as well as under stress conditions. The results of the LC-UV and LC-CAD methods were statistically compared through ANOVA and showed no significant difference (p > 0.05). Both proposed methods could be considered interchangeable and stability-indicating, and can be applied as an appropriate quality control tool for routine analysis of LDX in capsule.

A stability-indicating method using MEKC was validated for the analysis of olmesartan medoxomil in tablets. Successful separation was achieved using a fused silica capillary (40 cm x 50 µm i.d.); background electrolyte consisted of a combination of 10 mmol L-1 borate buffer and 5 mmol L-1 anionic detergent sodium dodecyl sulfate (95:5; v/v) pH 6.5; hydrodynamic mode at 50 mBar for 5 s; 25 kV separation voltage at 25 ºC; and column temperature 25 ºC with detection at 257 nm. The proposed method, validated following ICH guidelines, was applied to the determination of this antihypertensive with good results compared with an LC method.

This paper evaluates the adsorption capacity of zirconocene-based silica materials in the pre-concentration of antimicrobians (tetracycline, sulfamethoxazole and trimethoprim) in aqueous medium. These materials were prepared by grafting the zirconocene onto silicas pre-treated at different temperatures. The retention capacity of these materials was evaluated by off line SPE and HPLC-UV and the proposed methodology was validated in ultrapure, tap and river water. The recovery for tetracycline was 72% (in the solid phase A) and, for sulfamethoxazole and trimethoprim was 68 and 95% in the commercial C18, respectively. The target antimicrobians were not detected in the Arroio Dilúvio (Porto Alegre - RS).

A espectrofotometria derivada (ED) tem sido utilizada como uma importante ferramenta no controle de qualidade de medicamentos para a determinação simultânea de fármacos em sistemas multicomponentes. Esta técnica oferece uma alternativa para melhorar a sensibilidade e a seletividade na análise de misturas e está acessível à maioria dos laboratórios. O procedimento é simples, rápido e não necessita extração prévia da amostra. Este trabalho tem como objetivo fornecer subsídios para o desenvolvimento de método por espectrofotometria derivada, utilizando a técnica do ponto de anulação, visando utilizá-la como um método alternativo no controle de qualidade de fármacos associados e, em especial, nos estudos de dissolução. Muitos subsídios foram retirados da literatura, outros de experiências vivenciadas no laboratório durante o desenvolvimento do método por ED aplicado na análise de dois inibidores da protease do vírus da imunodeficiência humana. Várias ordens de derivadas, diferentes valores de lambda delta () e diferentes velocidades de varredura foram avaliados. Palavras chaves: Análise de misturas binárias. Espectrofotometria derivada. Método zero-crossing. ABSTRACT A contribution to the derivative spectrophotometry method Derivative spectrophotometry has been successfully used as a quality control tool in pharmaceutical analysis for the simultaneous determination of drugs in multi-component formulations. This technique, accessible to most laboratories, offers an alternative means of enhancing the sensitivity and specificity in mixture analysis. The procedure is simple, rapid and does not require any preliminary separations or treatment of the samples. The aim of this study is to provide pointers for the development of methods of analysis by derivative spectrophotometry (DS), using the zero-crossing technique, and to encourage professionals and researchers to use DS as an alternative method for quality control of drug combinations, especially in the study of dissolution. Much information, extracted from the literature, has been assembled here, together with the laboratory experience gained while developing a DS method to analyze a combination of two human immunodeficiency virus protease inhibitors. Various orders of derivatives, values of delta lambda () and scan speeds were tested. Keywords: Analysis of binary mixtures. Derivative spectrophotometry. Derivative zero-crossing method.

OBJETIVO: Determinar a concentração plasmática de zinco em crianças e adolescentes cirróticos e investigar a associação entre esses resultados e a ingestão dietética de zinco, os dados antropométricos e a gravidade da doença hepática. MÉTODOS: As concentrações plasmáticas de zinco foram avaliadas por espectrofotometria de absorção atômica em 30 crianças e adolescentes com cirrose (105,0±60,0 meses; 22 meninas) e 27 hígidas e sem doença hepática (122,3±47,3 meses, 14 meninas). Os dados relacionados ao zinco dietético foram avaliados por registro de ingestão alimentar de 3 dias. A antropometria incluiu peso, altura, espessura da dobra cutânea, circunferência braquial e área muscular do braço. A gravidade da doença hepática foi classificada de acordo com os critérios de Child-Pugh, MELD e PELD. RESULTADOS: As concentrações plasmáticas de zinco dos indivíduos controles e dos pacientes foram 105,69±19,46 e 75,44±24,45 μg/dL, respectivamente (p < 0,001). Nenhuma associação foi encontrada entre os índices antropométricos, a ingestão dietética e o zinco plasmático. Houve diferença estatística nas concentrações de zinco plasmático entre pacientes Child-Pugh B+C e controles (p < 0,001), e com relação ao PELD, entre pacientes abaixo e acima do ponto de corte 15 (p = 0,002). CONCLUSÃO: A prevalência de hipozincemia foi de 43% para pacientes com cirrose. A baixa concentração plasmática de zinco foi associada com a doença hepática grave; entretanto, a hipozincemia esteve presente mesmo em pacientes Child-Pugh A. Portanto, a suplementação de zinco deve ser considerada para os pacientes pediátricos cirróticos.OBJECTIVE: To determine plasma zinc concentrations in children and adolescents with cirrhosis and to investigate the association between these results and dietary zinc intake, anthropometric data, and severity of liver disease. METHODS: Plasma zinc concentration was assessed by atomic absorption spectrophotometry in 30 children and adolescents with cirrhosis (105.0±60.0 months; 22 girls) and 27 without liver disease (122.3±47.3 months, 14 girls). Dietary zinc data were evaluated by 3-day food intake records. Anthropometry measures included height, weight, skinfold thickness, brachial circumference, and upper arm muscle size. Severity of liver disease was classified according to the Child-Pugh, MELD, and PELD criteria. RESULTS: The mean (± standard deviation) plasma zinc concentrations in control subjects and patients were 105.69±19.46 and 75.44±24.45 μg/dL, respectively (p < 0.001). No associations were found between anthropometric measures, dietary zinc intake, and plasma zinc concentration. There was statistical difference related to plasma zinc concentrations between Child-Pugh B + C patients and control subjects (p < 0.001), and concerning PELD, between patients below the cutoff score of 15 and those above (p = 0.002). CONCLUSION: The prevalence of hypozincemia was 43% for patients with cirrhosis. Although low plasma zinc concentration was associated with more severe liver disease, it was present even in some Child-Pugh A patients. Therefore, zinc supplementation should be considered for cirrhotic children.

A espectrofotometria derivada (ED) tem sido utilizada como uma importante ferramenta no controle de qualidade de medicamentos para a determinação simultânea de fármacos em sistemas multicomponentes. Esta técnica oferece uma alternativa para melhorar a sensibilidade e a seletividade na análise de misturas e está acessível à maioria dos laboratórios. O procedimento é simples, rápido e não necessita extração prévia da amostra. Este trabalho tem como objetivo fornecer subsídios para o desenvolvimento de método por espectrofotometria derivada, utilizando a técnica do ponto de anulação, visando utilizá-la como um método alternativo no controle de qualidade de fármacos associados e, em especial, nos estudos de dissolução. Muitos subsídios foram retirados da literatura, outros de experiências vivenciadas no laboratório durante o desenvolvimento do método por ED aplicado na análise de dois inibidores da protease do vírus da imunodeficiência humana. Várias ordens de derivadas, diferentes valores de lambda delta (Δλ) e diferentes velocidades de varredura foram avaliados.

Summary: The authors investigated whether acoustic speaking voice analyses can be used to predict the beginning of mutation in 21 male members of a professional boys'' choir. Over a period of 3 years before mutation, children were examined every 3 months by ear, nose, and throat (ENT) and phoniatric specialists. At the same time, the voice was evaluated acoustically using analysis features of the Goettingen Hoarseness Diagram (GHD). Irregularity component and noise component, jitter, shimmer, mean waveform correlation coefficient, and fundamental frequency were determined from recordings of the speaking voice. Significant changes of acoustic features appeared 7 and 5 months before mutation onset, which indicates that vocal function is already restricted 6 months before mutation onset. This acoustic voice analysis is therefore suitable to support the care of the professional singing voice. [Copyright &y& Elsevier]

Two new stability-indicating liquid chromatographic methods using two detectors, an ultraviolet (UV) and a charged aerosol detector (CAD) simultaneously connected in series were validated for the assessment of lisdexamfetamine dimesylate (LDX) in capsule. The method was optimized and the influence of individual parameters on UV and CAD response and sensitivity was studied. Chromatography was performed on a Zorbax CN column (250 mm × 4.6 mm, 5 μm) in an isocratic elution mode, using acetonitrile and 20 mM ammonium formate at pH 4.0 (50:50, v/v) as mobile phase and UV detection at 207 nm. The developed method was validated according to ICH guidelines and the parameters’ specificity, limit of detection, limit of quantitation, linearity, accuracy, precision and robustness were evaluated. CAD is designated to be a non-linear detector in a wide dynamic range, however, the method was linear over the concentration range of 70–130 μg mL −1 in both detectors. The method was precise and accurate. Robustness study was performed by a Plackett–Burman design, delivering results within the acceptable range. Neither the excipients nor the degradation products showed interference in the method after studies of specificity as well as under stress conditions. The results of the LC-UV and LC-CAD methods were statistically compared through ANOVA and showed no significant difference ( p > 0.05). Both proposed methods could be considered interchangeable and stability-indicating, and can be applied as an appropriate quality control tool for routine analysis of LDX in capsule. [ABSTRACT FROM AUTHOR]

Two alternative methods were proposed to assay Fluoxetine Hydrochloride: a titrimetric method and another by HPLC using as mobile phase water pH 3.5: acetonitrile (65:35). These methods were applied to the determination of Fluoxetine as such or in formulations (capsules). The titrimetric method is an alternative for pharmacies and small industries. Both methods showed accuracy and precision and are an alternative to the official methods.