Stability of mixtures of ondansetron and haloperidol stored in infusors at different temperatures.

BACKGROUND AND OBJECTIVE: Mixing different drugs for use in continuous infusion systems is a common practice in palliative care, but analytical study of compatibility and stability is not always available. The objective of this work is to study the stability of solutions of ondansetron and haloperidol at different concentrations and temperatures all prepared in 0.9% NaCl and stored in infusors, with all cases protected from light. MATERIALS AND METHODS: The high performance liquid chromatography-Ultraviolet (HPLC-UV) method was employed for the determination of the drugs. The concentrations of the admixtures were 0.15-0.25 mg/mL and 0.3-0.4 mg/mL of haloperidol and ondansetron, respectively, with a storage temperature of 25°C and 37°C. RESULTS: All solutions were initially clear and colourless, but visible particles appear, in all cases, into the infusers after 2 days since their preparation. CONCLUSION: From the results obtained we can conclude that the mixtures prepared in the conditions previously described are stable less than 48 hours.

Applications of supercritical fluid chromatography-tandem mass spectrometry in pharmaceuticals.

Supercritical fluid chromatography (SFC) is a fully mature technique and can readily be coupled to mass spectrometers relatively easily. In the last years, supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) has had a great advance in productivity, due to increase in reliability and robustness of both SFC and MS systems, the need to push drug discovery faster, and as a potential solution to old problems unsolved and new problems yet to be encountered. This article will illustrate the role of SFC-MS analysis in drug discovery process.

Synthesis and acid digestion of biomorphic ceramics: determination of alkaline and alkaline earth ions.

Ceramic and glass are some of the more recent engineering materials and those that are most resistant to environmental conditions. They belong to advanced materials in that they are being developed for the aerospace and electronics industries. In the last decade, a new class of ceramic materials has been the focus of particular attention. The materials were produced with natural, renewable resources (wood or wood-based products). In this work, we have synthesised a new biomorphic ceramic material from oak wood and Si infiltration. After the material characterization, we have optimized the dissolution of the sample by acid attack in an oven under microwave irradiation. Experimental designs were used as a multivariate strategy for the evaluation of the effects of varying several variables at the same time. The optimization was performed in two steps using factorial design for preliminary evaluation and a Draper-Lin design for determination of the critical experimental conditions. Five variables (time, power, volume of HNO3, volume H2SO4 and volume of HF) were considered as factors and as a response the concentration of different metal ions in the optimization process. Interactions between analytical factors and their optimal levels were investigated using a Draper-Lin design.

Automated on-line preconcentration of palladium on different sorbents and its determination in environmental samples.

The determination of noble metals in environmental samples is of increasing importance. Palladium is often employed as a catalyst in chemical industry and is also used with platinum and rhodium in motor car catalytic converters which might cause environmental pollution problems. Two different sorbents for palladium preconcentration in different samples were investigated: silica gel functionalized with 1,5-bis(di-2-pyridyl)methylene tbiocarbohydrazide (DPTH-gel) and [1,5-Bis(2-pyridyl)-3-sulphophenyI methylene thiocarbonohydrazide (PSTH) immobilised on an anion-exchange resin (Dowex lx8-200)]. The sorbents were tested in a micro-column, placed in the auto-sampler arm, at the flow rate 2.8 mL min(-1). Elution was performed with 4 M HCl and 4 M HNO3, respectively. Satisfactory results were obtained for two sorbents.

Optical chemical biosensors for high-throughput screening of drugs.

Optical biosensors have been commercially available since the early 1990s, and have been used extensively in many areas of research in the life sciences. Optical biosensors developed for drug analysis generally exploit the high selectivity of the antigen-antibody and drug-protein interaction. Optical biosensors can be made based on optical diffraction or electro-chemiluminescence. High-throughput screening, (HTS) which includes automated preparation of a large number of samples and then screening of their properties in multi-well plates, improves the efficiency of research in many scientific areas, e.g., catalyst screening, food processing, chemical synthesis, drug discovery, absorption, distribution, metabolism, and excretion and toxicological and cell based screening. The three most common detection techniques used in HTS are UV-VIS absorbance, fluorescence and luminescence. In this review, we summarize some recent trends and developments in the construction of optical chemical biosensors used in high-throughput screening of drugs. Also, we have included environmental, biological and other medical applications of biosensors.

Application of flow injection on-line electrothermal atomic absorption spectrometry to the determination of rhodium.

A fully automated procedure for the determination of rhodium has been developed using flow injection (FI) on-line microcolumn preconcentration coupled with electrothermal atomic absorption spectrometry (ETAAS). The proposed FI manifold and its operation make possible the introduction of the total eluate volume into the graphite atomizer, avoiding the necessity for optimisation of subsampling the eluate. Rhodium is adsorbed on a microcolumn packed with 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide immobilized on silica gel (DPTH-gel). Under the optimum conditions, using a 60 s preconcentration time, a sample flow rate of 3.5 mL min(-1) and an injection volume of eluent of 50 microL, a linear calibration graph was obtained from 1 to at least 40 ng mL(-1) and the detection limit was 1 ng mL(-1). The proposed method has been successfully applied to the analysis of samples. Its performance was investigated against certified reference catalyst sample SRM-2557 and by recovery measurements on spiked samples (soil, foods and beverages).

Formacion de biocapas por Enterococcus faecalis y Enterococcus faecium sobre cateteres intravasculares / Bacterial biofilm formation on surfaces of intravascular catheters

La formación de biocapas por bacterias en la superficie de los catéteres intravasculares es un evento muy importante en la patogénesis y evolución de infecciones asociadas con el uso de estos dispositivos médicos. Los objetivos de este estudio fueron desarrollar biocapas y evaluar los eventos de adhesión y colonización "in vitro " de Enterococcus faecalis y Enterococcus faecium sobre catéteres intravasculares de teflón, poliuretano y vialón. Con este fin se utilizaron dos cepas, una de Enterococcus faecalis y una Enterococus faecium, en las que se determinó la susceptibilidad a antibióticos y la producción de P-lactamasas. Para la formación de biocapas se hicieron cortes de los catéteres y se pusieron en contacto con inocules independientes de 3 x IOS UFC/mI de Enterococcus faecalis y Enterococcus faecium, y se incubaron a 37ºC durante diferentes tiempos. Los resultados muestran que las dos cepas objeto de estudio presentaron resistencia a ampicilina, baja resistencia a gentamicina y sensibilidad a vancomicina; además de ser productoras de P-lactamasas de amplio espectro. El Enterococcus faecalis se adhiere mucho mejor que Enterococcus faecium a los catéteres intravasculares evaluados en este estudio. La mejor adherencia y formación de biocapas tanto de Enterococcus faecalis como de Enterococcus faecium se dio sobre el catéter intravascular de teflón. En conclusión se sugiere que a la hora de escoger un catéter intravascular, deberá ser de material de vialón ya que en él es donde los dos enterococos se adhieren muy mal, lo que conduciría a una deficiente formación de biocapas que evitaría complicaciones como endocarditis