Um método para determinação simultânea de ácido clavulânico (CA) e amoxicilina (AMO) foi desenvolvido utilizando a técnica de espectroscopia no infravermelho médio com transformada de Fourier acoplada ao acessório de reflexão total atenuada (ATR/FTIR). Utilizaram-se 27 e 8 amostras para os conjuntos de calibração e previsão, respectivamente. Os modelos de calibração foram desenvolvidos utilizando os algoritmos por mínimos quadrados parciais (PLS), PLS por intervalo (iPLS), PLS por sinergismo (siPLS) e PLS por exclusão (biPLS). Os melhores modelos foram aqueles que utilizaram o algoritmo biPLS. Obtiveram-se erro padrão relativo de previsão (RSEP) de 3,8 e 5,1% para CA e AMO, respectivamente. Os resultados obtidos pela metodologia proposta foram comparados com os obtidos por cromatografia líquida de alta eficiência (HPLC) e nenhuma diferença significativa foi observada. O método proposto utilizando ATR/FTIR associado a métodos de análise multivariados foi satisfatório para determinação de CA e AMO em produtos farmacêuticos.A method for simultaneous determination of clavulanic acid (CA) and amoxicillin (AMO) was developed using Fourier transform mid infrared technique coupled with attenuated total reflectance (ATR/FTIR) accessory. 27 samples were used as calibration set and 8 samples were used for prediction set. Calibration models were developed using partial least squares (PLS), interval PLS (iPLS), synergy PLS (siPLS) and backward PLS (biPLS). Multiplicative scatter correction and the mean centering were used and produced the best models. Relative standard error of prediction (RSEP) of 3.8% for CA and 5.1% for AMO were obtained using biPLS algorithm for ATR/FTIR data. Results obtained by the proposed methodology were compared with those using high performance liquid chromatography (HPLC) and no significant differences were obtained. The proposed method using ATR/FTIR combined to multivariate analysis methods was suitable for the simultaneous determination of CA and AMO in commercial pharmaceutical products.
Abstract. A dissolution method for benzoyl metronidazole (BMZ) oral suspensions was developed and validated using a high-performance liquid chromatography (HPLC) method. After determination of sink conditions, dissolution profiles were evaluated using different dissolution media and agitation speeds. The sample insertion mode in dissolution media was also evaluated. The best conditions were obtained using a paddle, 50 rpm stirring speed, simulated gastric fluid (without pepsin) as the dissolution medium, and sample insertion by a syringe. These conditions were suitable for providing sink conditions and discriminatory power between different formulations. Through the tested conditions, the results can be considered specific, linear, precise, accurate, and robust. The dissolution profiles of five samples were compared using the similarity factor (f 2 ) and dissolution efficiency. The dissolution kinetics were evaluated and described by the Weibull model. Whereas there is no monograph for this pharmaceutical formulation, the dissolution method proposed can be considered suitable for quality control and dissolution profile comparison of different commercial formulations.
Fluoroquinolones are a known antibacterial class commonly used around the world. These compounds present relative stability and they may show some adverse effects according their distinct chemical structures. The chemical hydrolysis of five fluoroquinolones was studied using alkaline and photolytic degradation aiming to observe the differences in molecular reactivity. DFT/B3LYP-6.31G* was used to assist with understanding the chemical structure degradation. Gemifloxacin underwent degradation in alkaline medium. Gemifloxacin and danofloxacin showed more degradation perceptual indices in comparison with ciprofloxacin, enrofloxacin and norfloxacin in photolytic conditions. Some structural features were observed which may influence degradation, such as the presence of five member rings attached to the quinolone ring and the electrostatic positive charges, showed in maps of potential electrostatic charges. These measurements may be used in the design of effective and more stable fluoroquinolones as well as the investigation of degradation products from stress stability assays.
Zinc (Zn) is an essential trace element for cellular viability, but concentrations above physiologic level may lead to cellular damage. The purpose of the present study was to evaluate the in vitro ZnCl 2 genotoxicity and cytotoxicity in human leukocyte cells. This was assessed in an unprecedented way that correlated the level of intracellular Zn after cell exposition with the cellular damage. The exposure to increased Zn concentrations (2.5-20 μg mL-1), showed significantly reduced cellular leukocyte viability. However, significant DNA damages were observed only when the Zn exposure concentrations were from 10-20 μg mL-1. The Zn intracellular levels found in leukocytes was from 72.25-268.9 ρg cell-1 , starting to induce cytotoxicity and genotoxicity at concentrations of 95.68 and 126.2 ρg cell-1 , respectively. The relationship between the exposure concentration and intracellular levels of Zn suggests that the influx of Zn, in the form of ZnCl 2 , occurs in human leukocytes under zero-order kinetics.
Meglumine Antimoniate did not interfere in the reproductive performance, after chronic exposition of dams. Data suggest that there is a gradual elimination of Meglumine Antimoniate by the maternal organism without damaging the future offspring.
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