Um método empregando LC-MS/MS foi desenvolvido para a análise de rosuvastatina em plasma humano, usando atorvastatina como padrão interno. Rosuvastatina é um fármaco para redução de lipídeos e prescrita para o tratamento do hipercolesterolemia e de dislipidimia. A extração em fase sólida (SPE) foi usada para purificação e pré-concentração do analito a partir da matriz do plasma humano. A separação cromatográfica foi conseguida em 6.0 min empregando fase móvel composta de 0.2% de ácido fórmico em água e acetonitrila (40: 60,v/v, na vazão de 1.0 mL min -1 e coluna YMC J'sphere ODS H-80, 150 x 4.6 mm, partículas de 4.0 μm. Na saída da coluna, a fase móvel foi dividida, sendo que 200 μL foram dirigidos para o espectrômetro de massas e 800 μL para o descarte. Pelo Monitoramento de Reação Múltipla (MRM), as transições foram medidas no modo positivo em m/z 482 -258 para rosuvastatina e m/z 559 -440 para o padrão interno, respectivamente. Uma validação detalhada do método foi realizada seguindo as recomendações do FDA americano e as curvas analíticas foram lineares no intervalo de 1.00 ng mL -1 a 50.00 ng mL -1 com coeficiente de correlação médio maior que 0.99. A recuperação absoluta foi maior que 50.14% para rosuvastatina e 54.65% para o padrão interno. Rosuvastatina foi estável por 138 dias a -70 ± 5 °C e por 24 horas à temperatura ambiente. Após a extração do plasma, as amostras reconstituídas de rosuvastatina permaneceram estáveis no auto injetor, a 10 °C, por 8 horas. Depois de submetidas a três ciclos de congelamento/descongelamento, não houve mudanças na recuperação do analito. O método é simples, específico, sensível, preciso, exato e apropriado para aplicações em bioequivalência e estudos farmacocinéticos. Foi aplicado com sucesso em um estudo piloto de bioequivalência da rosuvastatina, comprimidos -Zydus, Cadila, India versus comprimidos -Crestor, Astra Zeneca, EUA, em voluntários sadios do sexo masculino.A LC-MS/MS method has been developed for the estimation of rosuvastatin in human plasma using atorvastatin as internal standard. Rosuvastatin is a lipid-lowering drug prescribed for the treatment of hyper-cholestrolemia and dyslipidimia. Solid phase extraction (SPE) was used for the purification and pre-concentration of analyte from human plasma matrix. The chromatographic separation was achieved within 6.0 min by an isocratic mobile phase containing 0.2% formic acid in water and acetonitrile (40: 60, v/v), flowing through YMC J' Sphere ODS H-80, 150 x 4.6 mm, 4.0 μm analytical column, at a flow rate of 1.0 mL min -1 with split of 200 μL to mass spectrometer and 800 μL to waste. Multiple reaction monitoring (MRM) transitions were measured in the positive mode at m/z 482 and 258 for rosuvastatin and m/z 559 and 440 for internal standard respectively. A detailed validation of the method was performed as per USFDA guidelines and the standard curves were found to be linear in the range 1.0 ng mL -1 to 50.0 ng mL -1 with the mean correlation coefficient more than 0.99. The absolute recovery was more than 50.14% f...
The present paper reports synthesis and photoluminescence studies of cadmium tungstate (CdWO 4 ) and cerium-doped cadmium tungstate. The samples were synthesised by low cost and low temperature hydrothermal method and characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photoluminescence analysis. XRD pattern reveals that the CdWO 4 has monoclinic wolframite structure. The FTIR spectrum of cerium-doped CdWO 4 exhibits broadband below 700 cm À1 which is due to the d (Ce-O-C) mode. The TEM images show that size of particle is approximately 60-120 nm in both samples. A broad intense peak was observed at 474 nm when the samples were excited with 263 nm. A broad intense peak was observed at 475 nm when the samples were excited with 600 nm. The intensity of the 474 nm peak decreases with increase in cerium doping concentration. The observation of 475 nm peak when excited with 600 nm is upconversion luminescence. This upconversion emission is due to energy transfer upconversion process involving Cd 2þ ions and [WO 6 ] 6À ions. Ce 3þ ion is responsible for the peak shift of 6 nm.
We report synthesis of a cerium-activated strontium pyrophosphate (Sr2 P2 O7 ) phosphor using a high-temperature combustion method. Samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) and thermoluminescence (TL). The XRD pattern reveals that Sr2 P2 O7 has an α-phase with crystallization in the orthorhombic space group of Pnam. The IR spectrum of α-Sr2 P2 O7 displays characteristic bands at 746 and 1190 cm(-1) corresponding to the absorption of (P2 O7 )(-4) . PL emission spectra exhibit a broad emission band around 376 nm in the near-UV region due to the allowed 5d-4f transition of cerium and suggest its applications in a UV light-emitting diode (LED) source. PL also reveals that the emission originates from 5d-4f transition of Ce(3+) and intensity increases with doping concentration. TL measurements made after X-ray irradiation, manifest a single intense glow peak at around 192°C, which suggests that this is an outstanding candidate for dosimetry applications. The kinetic parameters, activation energy and frequency factor of the glow curve were calculated using different analysis methods.
The luminescence properties of Sr2GdTaO6 have been studied by keeping Eu(3+) as constant concentration and varying Er(3+) concentration. Sr2GdTaO6 phosphor doped with rare earth ions of Eu and Er having monoclinic phase of space group P21/n was synthesized, and their photoluminescence properties have been examined under UV excitation of wavelength 265 nm and 275 nm. PL emission exhibited around 468, 475, 580, 596, and 610 nm wavelength subsequently for various concentrations of Er(3+) for two different excitation wavelengths. By using xenon lamp as source and corresponding wavelength having excitation wavelength 265 and 275 nm, it is observed that the maximum light emission yield in region presenting a color-correlated temperature in the range of 1500-1900 K and 3000-6000 K.
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