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In this study, a solid-phase extraction (SPE)-high performance liquid chromatography (HPLC)-ultra violet (UV) method was developed for the determination of rivaroxaban (RIV), an oral anticoagulant drug, in human plasma samples. The concentration of RIV in plasma samples was increased 7.5 times and the interference coming from matrix components was avoided by using SPE. The extracted samples of RIV were analyzed by using an HPLC-UV method. RIV was approved in 2008 and many studies have been published in recent years in order to investigate its pharmacokinetic profile in various groups. In light of this information, it is clear that the RIV pharmacokinetic profile should be investigated in further studies; the HPLC-UV method presented in this study might be an easy method to apply, as it is a cheap and rapid alternative to HPLC-MS-MS for this purpose. A Phenomenex Luna 5-µm C18 100 Å LC column (250 × 4.6 mm) was used for the separation of RIV and prednisolone (internal standard). The total analysis time was <6 min. The method was validated according to the FDA guidelines and can be proposed for pharmacokinetic studies of RIV.

A simple, rapid and reproducible HPLC method was developed for the simultaneous determination of amlodipine and valsartan in their combined dosage forms, and for drug dissolution studies. A C18 column (ODS 2, 10 μm, 200 x 4.6 mm) and a mobile phase of phosphate buffer (pH 3.6 , 0.01 mol L-1):acetonitrile: methanol (46:44:10 v/v/v) mixture were used for separation and quantification. Analyses were run at a flow-rate of 1 mL min-1 and at ambient temperature. The injection volume was 20 μL and the ultraviolet detector was set at 240 nm. Under these conditions, amlodipine and valsartan were eluted at 7.1 min and 3.4 min, respectively. Total run time was shorter than 9 min. The developed method was validated according to the literature and found to be linear within the range 0.1 - 50 μg mL-1 for amlodipine, and 0.05 - 50 μg mL-1 for valsartan. The developed method was applied successfully for quality control assay of amlodipine and valsartan in their combination drug product and in vitro dissolution studies.
Desenvolveu-se método de HPLC rápido e reprodutível para a determinação simultânea de anlodipino e valsartana em suas formas de associação e para os estudos de dissolução dos fármacos. Utilizaram-se coluna C18 (ODS 2, 10 μm, 200 x 4,6 mm) e fase móvel tampão fosfato (pH 3,6, 0,01 mol L-1):acetonitrila: metanol para a separação e a quantificação. As análises foram efetuadas com velocidade de fluxo de 1 mL min-1 e à temparatura ambiente O volume de injeção foi de 20 μL e utilizou-se detector de ultravioleta a 240 nm. Sob essas condições, anlodipino e valsartana foram eluídas a 7,1 min e 3,4 min, respectivamente. O tempo total de corrida foi menor que 9 min. O método desenvolvido foi validado de acordo com a literatura e se mostrou linear na faixa de 0,1-50 μg mL-1 para anlodipino e de 0,05-50 μg mL-1 para valsartana. O método desenvolvido foi aplicado com sucesso para ensaios de controle de qualidade de associações de anlodipino e valsartana e nos estudos de dissolução in vitro

Rivaroxaban, an anti-clotting medication, acts at a crucial point in the blood-clotting process and stops the formation of blood clots. In this study, RP-HPLC method was developed for the determination of rivaroxaban in tablets (Xarelto ® (10 mg)). Phenomenex Luna 5 µm C18 100 Å LC Column (250 x 4.6 mm) was used at 40 o C. Isocratic elution was performed with ACN:Water (55:45 v/v) mixture. The flow rate was 1.2 mL min -1 and UV detection was at 249 nm. Internal standard (Caffeine) and rivaroxaban were eluted within 2.21 and 3.37 minutes, respectively. The developed method was validated according to the ICH guidelines and found to be linear within the range 0.005 -40.0 µg mL -1 . The method was accurate, precise, robust and rapid. Thus, it was applied successfully for the quality control assay of rivaroxaban in tablet dosage form.Uniterms: HPLC. Rivaroxaban. Validation. System suitability. Stability-indicating. Pharmaceutical dosage form.Rivaroxabana, fármaco anticoagulante, atua em um ponto crucial no processo de coagulação do sangue e impede a formação de coágulos sanguíneos. Neste estudo, desenvolveu-se método de RP-HPLC para a determinação de rivaroxabana em comprimidos (Xarelto ® (10 mg)). Utilizou-se coluna LC (250 x 4,6 mm) Phenomenex Luna C18 5 mm 100 Å a 40 o C. Realizou-se eluição isocrática com ACN: água (55:45 v/v). O fluxo foi de 1,2 mL min-1 e a detecção de UV foi a 249 nm. Padrão interno (cafeína) e rivaroxabana eluíram em 2,21 e 3,37 minutos, respectivamente. O método desenvolvido foi validado de acordo com as diretrizes do ICH e mostrou-se linear na faixa 0,005-40,0 mg mL -1 . O método foi exato, preciso, robusto e rápido. Assim, foi aplicado com êxito para o ensaio de controle de qualidade da Rivaroxabana na forma de comprimidos.Unitermos: HPLC. Rivaroxabana. Validação. Adequação do sistema. Indicador de estabilidade. Forma farmacêutica.

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A new series of diorganotin complexes of the type R 2 SnL (L 1 : N-(2-hydroxy-5-chlorophenyl

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IIIa) were prepared by the reaction of diphenyltin dichloride on the corresponding Schiff bases. The Schiff bases were the reaction products of 2-hydroxy-4-nitroaniline and appropriate salicylaldehydes. All the compounds were characterized by elemental analysis, 1 H-NMR, 13 C-NMR, IR and mass spectroscopy. Compound IIIa was also characterized by single crystal X-ray diffraction and shows a C 2 NO 2 coordination geometry nearly half-way between a trigonal bipyramidal and square pyramidal arrangement. In the solid state, π − π interactions exist between the aniline fragments of neighbouring molecules.