High-performance liquid chromatographic analysis of amphotericin B in rat plasma using α-naphthol as an internal standard

A simple, sensitive and accurate reverse phase high-performance liquid chromatographic (RP-HPLC) method with photo-diode array detector (PDA) was developed and validated for the determination of amphotericin B (AMB) in the rat plasma using a new internal standard (IS) α-naphthol. The plasma samples were subjected to protein precipitation with methanol prior to a HPLC analysis. Chromatographic separations were achieved on a Nucleosil® 100-5C18 (150 mm × 4.6 mm) column. The mobile phase consisted of acetonitrile and sodium acetate buffer (pH 4; 10 mM) in a gradient mode. Detection was carried out at a wavelength of 407 and 294 nm for AMB and IS, respectively. The retention times of AMB and IS were about 6.8 and 7.8 min, respectively. The calibration curve was linear in the range of 10-2000 ng mL−1 for AMB (r2 > 0.998). No significant matrix effect was observed on quantification of AMB or IS. At three quality control concentrations of 20, 500, and 2000 ng mL−1, the intra-day and inter-day relative standard deviation ranged from 1.13% to 4.91%. The limit of detection (LOD) was 5 ng mL−1 and the limit of quantification (LOQ) was 10 ng mL−1 for AMB in rat plasma. This method is simple, sensitive, rapid and does not require any extensive sample purification before injecting into HPLC

Nanoparticles enhance per oral bioavailability of poorly available molecules: epigallocatechin gallate nanoparticles ameliorates cyclosporine induced nephrotoxicity in rats at three times lower dose than oral solution

Epigallocatechin gallate (EGCG) has been proven to have great therapeutic potential in treatment and prophylaxis of various disorders, which are mediated by free radicals and oxidative stress. However, the poor biopharmaceutical properties and pharmacokinetics including poor stability in gastro-intestinal tract, low intestinal permeability and short plasma half life, have hindered its clinical development. In an attempt to overcome the above problems, EGCG was incorporated into PLGA nanoparticles. The nanoparticles were made following modified double emulsion method employing Didodecyldimethylammonium bromide (DMAB) as stabilizer. The particles were of similar to 130 nm size and polydispersity index of similar to 0.196 with encapsulation efficiency of 70% at 25% drug loading (w/w of polymer). The in vivo antioxidant efficacy of the EGCG nanoparticulate formulation was evaluated in a rat model of Cyclosporine (CyA)-induced chronic nephrotoxicity. Intraperitoneal (i.p.) administered EGCG solution was found to be efficacious in reducing the CyA-induced nephrotoxicity as evident form blood urea nitrogen, plasma creatinine and other parameters including plasma and renal malondialdehyde and glutathione levels, whereas orally administered EGCG solution was found to be ineffective. On the other hand, nanoparticulate formulation of EGCG administered per oral was found to be equally efficacious as i.p. administered EGCG solution in ameliorating CyA-induced renal damage at three times reduced dose. Together, these results suggest the potential of biodegradable nanoparticles in improving the therapeutic efficacy of EGCG

Phenology and reproductive traits of peaches and nectarines in Central-East Argentina Fenologia e comportamento reprodutivo de pêssego no centro-leste da Argentina

In Santa Fe, the central-east area of Argentina, the expansion of fruit tree crops requires the introduction and evaluation of low chilling varieties. The aims of this study was to characterize the phenological behaviour and the reproductive traits of peach (Prunus persica L. Batsch) and nectarine varieties with chilling requirements ranging from 150 to 650 chilling hours (CH). Low chilling varieties (< 450 CH) had higher flower density (22.0-56.5 flowers m-1), fruit set (26.0-56.7%), fruit yield (9.3-36.6 kg per plant), and low coefficient of fruit yield variability than varieties with a higher chilling requirement (>500 CH). The phenology of high chilling requirement varieties had the advantage that blooming and fruit set happened after the period of late frost occurrence. However, they did not satisfy their chilling requirement, showing an inadequate vegetative and reproductive behaviour. Low chilling varieties began to sprout during July, and the period of full bloom occurred from July 14th to August 4th. Fruit harvest was initiated on October 19th with the cv. 'Flordastar' and it extended for 58 days. However, on low chilling varieties the harvest time was reduced in ten days. Flower density, fruit set and fruit yield showed a negative relationship with the chilling requirement of the variety.<br>Na região centro-leste do estado de Santa Fé, Argentina, para a expansão dos frutais é preciso introduzir variedades de baixo requerimento de frio. O objetivo deste estudo foi caracterizar o comportamento durante as fases de crescimento e frutificação de variedades de pêssego (Prunus persica L. Batsch) e nectarina com requerimentos de frio que variam entre 150-650 horas de frio (CH). As variedades de pêssego de baixa necessidade de frio (< 450 CH) mostraram maior densidade de flores (22.0-56.5 flores m-1), de estabelecimento de frutos (26.0-56.7%), e rendimento de fruta (9.3-36.6 kg por planta) comparado com variedades de pêssego com necessidade de frio maior (>500 CH). As variedades de maior necessidade de frio tiveram a vantagem da floração, e o estabelecimento dos frutos aconteceu depois do período de risco de geadas. Porém, essas variedades não têm satisfeita sua necessidade de frio, apresentando comportamento vegetativo e reprodutivo inadequado. As variedades de baixa necessidade de frio brotaram entre 4 a 31 de julho e o período de plena floração aconteceu entre 14 de julho a 4 de agosto. A colheita de fruta começou em 19 de outubro com o cv. 'Flordastar', e sua duração foi de 58 dias. Para as variedades de baixa necessidade de frio o período de colheita foi dez dias mais curto

Optimal testing for additivity in multiple nonparametric regression

Additive models, Functional hypothesis testing, Minimax testing, Nonparametric regression, Wavelets,