A reverse phase HPLC method is described for the determination of 6-mercaptopurine in bulk and tablets. Chromatography was carried on a C 18 column using a mixture of acetonitrile and 0.05 mol/L sodium acetate buffer (10:90 v/v) as the mobile phase at a flow rate of 1 mL/min -1 with detection at 324 nm. The retention time of the drug was 3.25 min. The detector response was linear in the concentration of 0.01-5 μg/mL. The limit of detection and limit of quantification were 17 and 52 ng/mL respectively. The method was validated by determining its sensitivity, linearity, accuracy and precision. The proposed method is simple, economical, fast, accurate and precise and hence can be applied for routine quality control of mercaptopurine in bulk and tablets.Uniterms: 6-Mercaptopurine/determination. High perfomance liquid chromatography/reverse phase/ quantitative analysis. Pharmaceutical formulations/quality control Descreve-se método de CLAE em fase reversa para a determinação de mercaptopurina a granel e em comprimidos. A cromatografia foi realizada em coluna C18, utilizando mistura de acetonitrila em tampão acetato de sódio 0,05 mol/L (10:90 v/v) como fase móvel, com fluxo de 1 mL/min e detecção a 324 nm. O tempo de retenção do fármaco foi de 3,25 min. A resposta do detector foi linear na concentração de 0,01-5 μg/mL. O limite de detecção e o limite de quantificação foram de 17e 52 ng/mL, respectivamente. O método foi validado pela determinação de sua sensibilidade, linearidade, acurácia e precisão. O método proposto é simples, econômico, rápido, acurado e preciso e, então, pode ser aplicado para controle de qualidade de rotina da mercaptopurina em batelada e em comprimidos.Unitermos: Mercaptopurina/determinação. Cromatografia líquida de alta eficiência/fase reversa/análise quantitativa. Formulações farmacêuticas/controle de qualidade.

The objective of the current study was to develop a simple, accurate, precise and rapid reversed-phase HPLC method and subsequent validation as per ICH guidelines for the determination of venlafaxine hydrochloride in pharmaceutical dosage forms. The proposed RP-HPLC method utilizes a 5 µm Varian ® Microsorb-MV 100 C 18 column (250 mm x 4.6 mm) at ambient temperature. A 2 3 factorial design consisting of 3 factors at 2 levels was set up to standardize the chromatographic conditions. A numerical optimization technique employing the desirability approach was used to locate the optimum chromatographic conditions. The optimum mobile phase consisted of acetonitrile, 0.04 M potassium dihydrogen phosphate buffer and methanol (45:25:30, v/v), with pH adjusted to 5.5 using 10% phosphoric acid solution. The mobile phase was delivered isocratically at a flow rate of 1 mL/min with UV detection at 224 nm. The calibration plots constructed using the optimized chromatographic conditions displayed good linear relationship in the concentration range of 1-50 µg/mL with r=0.9992. The method was validated for precision, accuracy, robustness and recovery. The minimum detectable and minimum quantifiable amounts were found to be 0.568 and 1.72 µg/mL, respectively and the method was found to be reproducible from the statistical data generated. Venlafaxine hydrochloride was eluted at 3.43 min.

A reverse phase HPLC method is described for the determination of esmolol hydrochloride in bulk and injections. Chromatography was carried on a C18column using a mixture of acetonitrile, 0.05 M sodium acetate buffer and glacial acetic acid (35:65:3 v/v/v) as the mobile phase at a flow rate of 1 mL/min with detection at 275 nm. The retention time of the drug was 4.76 min. The detector response was linear in the concentration of 1-50 μg/mL. The limit of detection and limit of quantification was 0.614 and 1.86 μg/mL respectively. The method was validated by determining its sensitivity, linearity, accuracy and precision. The proposed method is simple, economical, fast, accurate and precise and hence can be applied for routine quality control of esmolol hydrochloride in bulk and injections.

Phyllanthus emblica Linn. (amla) is used in Ayurveda, the ancient Indian system of medicine and its major constituent is vitamin C which has effective free radical scavenging property. The purpose of this study was to evaluate the in vitro antioxidant activity and the bioavailability profile of vitamin C in amla and its combinations with piperine and ginger in comparison to synthetic vitamin C using New Zealand rabbits. In vitro antioxidant activity studies of synthetic vitamin C, amla, amla with piperine and amla with ginger were carried out using different models such as 2,2-Diphenyl-1-picrylhydrazyl, Nitric Oxide, Hydrogen peroxide scavenging methods, Total reductive capability and Oxygen Radical Absorbance Capacity estimation. The study results showed that synthetic vitamin C, amla, amla with piperine and amla with ginger possess significant in vitro antioxidant activity. For bioavailability studies, synthetic vitamin C, amla, amla with piperine and amla with ginger 100 mg/kg, were administered orally and the serum samples were analyzed by HPLC at 0, 1, 2, 3, 4, 6, 8, 10, 12 and 24 hours. Bioavailability studies revealed that amla with piperine combination has higher concentration of vitamin C when compared to synthetic vitamin C. This is probably due to presence of piperine, which is a bioavailability enhancer. The present study supports the fact that amla with piperine combination can be an alternative to synthetic vitamin C.Uniterms: Phyllanthus emblica Linn. Vitamin C/antioxidant activity/in vitro study. Vitamin C/ bioavailability. Vitamin C/synthetic/antioxidant activity. Ginger. Piperine.Phyllanthus emblica Linn. (amla) é utilizada na medicina Ayurveda, medicina da Índia antiga e seu principal constituinte é a vitamina C, que possui propriedade sequestrante de radicais livres. O propósito deste estudo foi avaliar a atividade antioxidante in vitro e o perfil de biodisponibilidade da vitamina C na amla e suas combinações com piperina e gengibre em comparação com a vitamina C sintética, utilizando coelhos da Nova Zelândia. Os estudos de atividade antioxidante in vitro de vitamina C sintética, amla, amla com piperina e amla com gengibre foram realizados utilizando-se diferentes modelos para sequestrantes, como 2,2-difenil-1-picrilidrazil, óxido nítrico, peróxido de hidrogênio, capacidade redutiva total e a estimativa da capacidade de absorvância do radical oxigênio. Os resultados do estudo mostraram que vitamina C sintética, amla, amla com piperina e amla com gengibre possuem atividade antioxidante in vitro significativa. Para os estudos de biodisponibilidade, administraram-se oralmente vitamina C sintética, amla, amla com piperina e amla com gengibre 100 mg/kg e as amostras de soro foram analisadas por CLAE em 0, 1, 2, 3, 4, 6, 8, 10, 12 e 24 horas. Os estudos de biodisponibilidade revelaram que a associação de amla com piperina tem maior concentração de vitamina C, quando comparada com a vitamina C sintética. Este efeito é provavelmente devido à presença de piperina, que é intensificador de biodisponibil...