Use of semipreparative supercritical fluid chromatography to obtain small quantities of the albendazole sulfoxide enantiomers.

The semipreparative separation of the albendazole sulfoxide enantiomers using chiral supercritical fluid chromatography is presented in this work. For this purpose, a modular SFC chromatograph was adapted to work at semipreparative scale and a Chiralpak AD (250 x 10 mm) column was used. Different injection volumes were evaluated in order to obtain high purities and throughputs. Using the maximum load, it was possible to obtain 37 mg/h of the first eluted enantiomer with a purity of 99.9%, and 36.5 mg/h of the second eluted enantiomer with a purity of 95%.

Separation of antifungal chiral drugs by SFC and HPLC: a comparative study.

The enantiomeric separation of several compounds, including an antifungal drug and several of its precursors, using HPLC and SFC is described in this work. The columns employed were based on polysaccharide derivatives and the results show that most of the separations obtained by SFC are better, in terms of high resolution and short analysis time, than those obtained by HPLC. Only one compound could not be resolved using SFC but, in this case, HPLC provided baseline resolution.

Separation of albendazole sulfoxide enantiomers by chiral supercritical-fluid chromatography.

The enantioseparation of albendazole sulfoxide (ABZSO) by chiral supercritical-fluid chromatography (SFC) on two columns, based on the polysaccharide derivatives Chiralpak AD and Chiralcel OD, was studied. The effect of different modifiers, methanol, ethanol, 2-propanol, and acetonitrile, was examined. The results showed that ABZSO can be separated on both columns, using an alcohol-type modifier. Using the Chiralpak AD column, the best results were obtained with 2-propanol and, in the case of the Chiralcel OD, with methanol.

Applications of the Chiralpak AD and Chiralcel OD chiral columns in the enantiomeric separation of several dioxolane compounds by supercritical fluid chromatography.

Two chiral columns based on polysaccharide derivatives (Chiralpak AD and Chiralcel OD) have been tested for the chiral separation of several dioxolane compounds, using supercritical fluid chromatography. The compounds studied included ketoconazole and some of its precursors. The effect of the different modifiers and the pressure, on the chromatographic parameters was also evaluated. In general, the alcohol modifiers provided better results than acetonitrile, and all the compounds could be separated with these two columns, but the selection of the column depends on the kind of compound.

Odour and VOC confining in large enclosures using air curtains.

Experiments were conducted on a two stream air-curtain prototype designed for VOC and odour confinement in a truck unloading area. The emphasis was placed on the air supply device. Measurements using tracer gas techniques were performed to assess the effectiveness of the system in terms of air tightness. Leakage flow rate was estimated for various feeding arrangements. Flow visualisations and particle image velocimetry measurements were carried out for a better understanding of the flow dynamics. Evidence was given of the improvements brought by the herein referred to, 'double flux' configuration in comparison to traditional designs. After a brief description of the experimental facility and the basic principle underlying the approach developed, the main results are reported and discussed and recommendations are drawn. Considerations about where the effort will be directed in future works are provided.

Separation of ketoconazole enantiomers by chiral subcritical-fluid chromatography.

The separation of ketoconazole enantiomers by subcritical-fluid chromatography using an amylose-based column is described. Drastic changes in the resolution have been obtained for the different organic modifiers evaluated, with ethanol providing the best results. Other chromatographic parameters such as temperature, pressure and flow-rate have also been studied. The best results in terms of resolution and analysis time were obtained using 30% ethanol (containing 0.1% triethylamine and 0.1% trifluoroacetic acid), a pressure of 300 bar, a temperature of 35 degrees C and a flow-rate of 3 ml/min. Under these conditions the ketoconazole enantiomers are resolved in a short time (less than 7 min) and with high resolution (4.29).

Chiral separation of four 1,3-dioxolane derivatives by supercritical fluid chromatography on an amylose-based column.

The chiral separation of four 1,3-dioxolane derivatives by supercritical fluid chromatography on an amylose-based column is described. The effects of mobile phase composition, temperature and pressure have been investigated. The nature of the modifier is the parameter which has the highest impact on the chiral resolution and it is more important than the polarity of the mobile phase. The organic modifier used for the best enantiomeric separation was different for each compound, because it depends strongly on the molecular structure of the compound.