Development and validation of a dissolution test for telithromycin in coated tablets

A dissolution test for telithromycin tablets was validated and developed. In order to choose the most discriminatory one, the conditions to carry out are 900 mL of sodium phosphate buffer at pH 7.5, paddles at 50 rpm stirring speed, time test set to 60 min and using USP apparatus 2 with paddles. The UV spectrophotometric method for determination of telithromycin released was developed and validated. The method presents linearity (r = 1) in the concentration range of 20-60 µg/mL. Precision and recoveries were good, 100.62 and 97.06%, respectively. The method was successfully used for the dissolution test of telithromycin tablets.

Development of new dissolution test and HPLC-RP method for anti-parasitic ornidazole coated tablets

This work aimed the development and validation of a new dissolution test for ornidazole coated tablets. The dissolution conditions were determined after testing Sink conditions, dissolution medium, apparatus, stirring speed, 24 h stability and medium filtration influence. The best conditions were paddle at a stirring speed of 75 rpm and 900 mL of 0.1 M HCl. A new HPLC quantification method was developed and validated. The dissolution test and quantification method showed to be adequate for their purposes and could be applied for quality control of ornidazole coated tablets, since there is no official monograph.

Preparation of glasses and glass ceramics of heavy metal oxides containing silver: optical, structural and electrochemical properties

Silver containing heavy metal oxide glasses and glass ceramics of the system WO3-SbPO4-PbO-AgCl with different AgCl contents have been prepared and their thermal, structural and optical properties characterized. Glass ceramics containing metallic silver nanoparticles have been prepared by annealing glass samples at temperatures above the glass transition and analyzed by transmission electron microscopy and energy dispersive X-ray microanalysis. The presence of the metallic clusters has been also confirmed by the observation of a surface plasmon resonance band in the visible range. Cyclic voltammetric measurements indicated the presence of metallic silver into the glasses, even before to perform the thermal treatment.

Enhanced photocatalytic activity of TiO2 films by modification with polyethylene glycol

Titanium dioxide porous thin films on the Anatase phase were deposited onto glass slides by the sol-gel method assisted with polyethylene glycol (PEG). The dip-coated films were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA and DTG), UV-visible spectroscopy and X-ray diffraction (XRD). The photocatalytic activity of the films was determined by means of methyl-orange oxidation tests. The resultant PEG-modified films were crack-free and developed a porous structure after calcination at 500 °C. Photo-oxidation tests showed the dependency of catalytic activity of the films on the number of layers (thickness) and porosity, i.e. of the interfacial area.

Sodium dodecyl sulfate coated γ-alumina support modified by a new Schiff base for solid phase extraction and flame-AAS determination of lead and copper ions

A simple and fast approach for solid phase extraction is herein described, and used to determine trace amounts of Pb2+ and Cu2+ metal ions. The solid phase support is sodium dodecyl sulfate (SDS)-coated γ-alumina modified with bis(2-hydroxy acetophenone)-1,6-hexanediimine (BHAH) ligand. The adsorbed ions were stripped from the solid phase by 6 mL of 4 M nitric acid as eluent. The eluting solution was analyzed by flame atomic absorption spectrometry (FAAS). The sorption recovery of metal ions was investigated with regard to the effects of pH, amount of ligand, γ-alumina and surfactant and the amount and type of eluent. Complexation of BHAH with Pb2+ or Cu2+ ions was examined via spectrophotometry using the HypSpec program. The detection limit for Cu2+ was 7.9 µg L-1 with a relative standard deviation of 1.67%, while that for Pb2+ was 6.4 µg L-1 with a relative standard deviation of 1.64%. A preconcentration factor of 100 was achieved for these ions. The method was successfully applied to determine analyte concentrations in samples of liver, parsley, cabbage, and water.

Inertization of small-scale chemical wastes using iron phosphate glass

The viability of small-scale heavy-metal waste immobilization into iron phosphate glasses was investigated. Several waste forms containing different amounts of heavy-ion wastes were evaluated (5%, 10%, 15%, 20%, 26%, 33%, 40% and 50% by mass) and their X-ray diffraction patterns revealed that no crystallization occurred in glasses with waste concentrations up to 26%. The dissolution rates for all of the reported glass compositions (ca. 10-8 g cm-2 min-1) are similar to those reported for the materials most commonly used for waste vitrification. Iron phosphate glasses thus proved to be very useful for the immobilization of heavy-metal wastes, exhibiting good contention and chemical durability comparable to that of borosilicate glasses.

Determination of carbon monoxide using a coated quartz crystal sensor

Carbon monoxide was detected and determined by a piezoelectric quartz crystal sensor coated with nickel(II)-phthalocyanine 50 % (v/v) solution in glycerine. Studies on the effect of temperature, flow rate, and some possible interferents were carried out. Calibration curves, sensor stability (lifetime) and the precision of measurements were also verified. The resulting selectivity is probably due to the coordinative binding between the electronically unsatured metal complexes and the analyte. The analytical curve is linear in the concentration range 0.10 to 1.0 % (v/v).

Physical characteristics of oily spraying liquids and droplets formed on coffee leaves and glass surfaces

The physical characteristics of a spray liquid are important in getting a good droplet formation and control efficiency over a particular target. As a function of these characteristics, it is possible to decipher which is the best adjuvant based on the respective concentration used during the spray. Therefore, ten spraying liquids were prepared, which varied in concentrations of pesticide lufenuron + profenofos, mineral oil, water and manganese sulfate. Pendant droplets formed from these mixtures were measured to examine their impact on surface tension. Droplets were applied to the surface of coffee leaves and the surface tension, contact angle formed and the leaf area wetted by the droplet, were measured. A smooth glass surface was taken as a comparative to the coffee leaves. The highest concentrations of oil resulted in lower surface tension, smaller contact angles of droplets on leaf surfaces and larger areas wetted by the droplets. Both surfaces showed hydrophilic behavior.

Glass pipette-carbon fiber microelectrodes for evoked potential recordings

Current methods for recording field potentials with tungsten electrodes make it virtually impossible to use the same recording electrode also as a lesioning electrode, for example for histological confirmation of the recorded site, because the lesioning procedure usually wears off the tungsten tip. Therefore, the electrode would have to be replaced after each lesioning procedure, which is a very high cost solution to the problem. We present here a low cost, easy to make, high quality glass pipette-carbon fiber microelectrode that shows resistive, signal/noise and electrochemical coupling advantages over tungsten electrodes. Also, currently used carbon fiber microelectrodes often show problems with electrical continuity, especially regarding electrochemical applications using a carbon-powder/resin mixture, with consequent low performance, besides the inconvenience of handling such a mixture. We propose here a new method for manufacturing glass pipette-carbon fiber microelectrodes with several advantages when recording intracerebral field potentials

Stability of volatile profile and sensory properties of passion fruit juice during storage in glass bottles

This study aimed at assessing the stability of passion fruit juice in glass bottles during a 120-day storage period, regarding its volatile compounds profile and sensory properties (aroma and flavor). Samples were obtained from a Brazilian tropical juice industry (Fortaleza, Brazil) and submitted to sensory and chromatographic analyses. The characteristic aroma and flavor of passion fruit were evaluated by a trained panel with a non-structured scale of 9 cm. The headspace volatile compounds were isolated from the product by suction and trapped in Porapak Q, analyzed through high-resolution gas chromatography and identified through gas chromatography-mass spectrometry (GC-MS). Twelve odoriferous compounds were monitored: ethyl butanoate, ethyl propanoate, 3-methyl-1-butanol, 3-methyl-2-butenol, (E)-3-hexenol, (Z)-3-hexenol, 3-methylbutyl acetate, benzaldehyde, ethyl hexanoate, hexyl acetate, limonene and furfural. The slight variations observed in the volatile profile were not enough to provoke significant changes in the characteristic aroma and flavor of the passion fruit juice.

Effects of different packaging techniques on the microbiological and physicochemical properties of coated pumpkin slices

Abstract In this study the effects of zein film coating along with benzoic acid on the quality of sliced pumpkin samples, which were packaged with different techniques were investigated. The samples were allocated into different groups and were treated with different processes. Following processing, the samples were stored at +4 °C for twenty days. Physicochemical and microbiological analyses were carried out on the samples once every five days during the storage period. According to color analysis, the L* value was observed to have significantly decreased in the processed and packaged samples in comparison with the control group. Besides, a* and b* values increased in all groups. It was determined that zein film alone did not exhibit the expected effectiveness against moisture loss in the samples. According to the results of microbiological analysis, a final decrease at approximately 1.00 log level was determined in total count of mesophilic aerobic bacteria (TMAB) in the group which was vacuum packaged in PVDC with zein coating when compared with the initial TMAB. Furthermore, no molding occurred in zein-coated group on the last day of the storage period, while massive mold growth was noted in the group which was packaged without any pretreatment procedure.

Performance of lowland rice seeds coated with dolomitic limestone and aluminum silicate

The objective of this study was to evaluate the performance of seeds of two cultivars of lowland rice (Oryza sativa L.), coated with dolomitic limestone and aluminum silicate. It was used a completely randomized experimental design, with the treatments arranged in a 4 X 2 factorial scheme [4 treatments: dolomitic limestone; dolomitic limestone + aluminum silicate; aluminum silicate, at the dosages of 50 g/100 kg of seeds; and control (without the products) X 2 cultivars: IRGA424 and IRGA 422 CL], totaling eight treatments with four replications each. The variables analyzed were: fresh and dry weights of aerial biomass; plant height; leaf area at 10, 20, and 30 days after emergence (DAE). The physiological quality of seeds was also assessed using tests of: seed emergence; first count of germination; emergence speed index; and field emergence. It was concluded that the coating of rice seeds with dolomitic limestone and aluminum silicate does not affect seed germination and field seedling emergence. Aluminum silicate used via seed coating on cultivar IRGA 424 promoted greater leaf area, after 20 DAE. The dolomitic limestone and the aluminum silicate used via seed coating generated plants with larger dry biomass, after 20 DAE, for the cultivar IRGA 422 CL.