Smectites and zeolites in ash from the 2010 summit eruption of Eyjafjallajökull volcano, Iceland

Hydrothermal alteration minerals are often incorporated in volcanic ash from phreatic and phreatomagmatic activity. Here we assess the presence and abundance of such minerals in the ash materials produced during the April- May 2010 initial phreatomagmatic (phase I) and subsequent magmatic (phases II and III) eruptions of Eyjafjallajökull volcano, Iceland. The results of X-ray diffraction analyses reveal significant quantities of smectites (up to 4 wt%, mainly as saponite) and zeolites (up to 7 wt%) in ash from phase I. While a minor amount of smectites (<0.5 wt%) is present in ash from the subsequent weak explosive activity (phase II), both smectites and zeolites are absent in phase III ash. This material was generated following abrupt rejuvenation of explosive activity in the absence of magma-ice/water interaction. Smectites and zeolites in phase I ash result primarily from scouring of altered volcanic rocks in the subsurface, although some may derive also from water-rock interaction within the summit ice cauldrons through which fragmented magma was injected.We show that incorporation of smectites and zeolites in phase I ash can explain its anomalously high specific surface area. Further, the presence of these minerals in ash may enhance its ability to act as ice nuclei as well as favour particle aggregation processes in the volcanic plume/cloud. Finally, the Eyjafjallajökull eruption represents another case in which ash fallout acted as an exogenic source of 2:1-type clay minerals in volcanic soils

Crystallization and Crystallinity of Fluticasone Propionate

Solubilization of fluticasone propionate (FP) was effected using aqueous solutions of (i) different grades of poly(ethylene glycol) (PEG), (ii) methanol, and (iii) acetone to enable antisolvent crystallization by the addition of water. The solubility of FP in acetone was significantly higher than in PEG 400 or PEG 6000, and FP solubility was observed to be nonideal in either cosolvent. Crystallization of FP was instantaneous upon addition of water as antisolvent, with nucleation occurring during the mixing phase. The smallest crystals were produced in all cases from PEG solvents, which was attributed to a greater degree of nucleation and microcrystals of a size-range were produced. Crystals produced from PEG solvents also displayed a resistance to agglomeration and Ostwald ripening, which was observed to affect the morphology of FP crystallized from either methanol or acetone by the addition of water. In spite of the very rapid kinetics of solid formation, FP crystallized as the stable Form I polymorph from PEG 400 and PEG 6000. Conversely, mechanical milling of highly crystalline particles resulted in the generation of disorder in the crystals, which was apparent from surface dynamic vapor sorption analysis. The generation of FP microcrystals with a small size range from environmentally benign PEG solvents as the stable crystalline form represents an improvement over current crystallization and micronization techniques for the production of inhalable FP.Peer reviewe