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The catalytic pyrolysis of naphtha has been carried out with 5 mm KVO3-impregnated α-Al2O3. The yields of ethylene and propylene exhibit about 10% and 5% higher values compared to the thermal pyrolysis in a vacant tube at the same operation condition. This increase in the olefin yield comes from the thermal effect through the better heat transfer. The amount of coke accumulated on the catalyst during the pyrolysis increases with an increase in the reaction temperature and the axial length of the reactor. The role of KVO3 is to suppress the coke deposition on the catalyst surface. The addition of B2O3 to the KVO3/α-Al2O3 system causes a strong interaction between KVO3 and α-Al2O3. The results of temperature-programmed reduction and X-ray photoelectron spectroscopy suggest that KVO3 may be reduced to KVO1.5 during the pyrolysis reaction. The weight loss of K and V in the catalyst occurs during the pyrolysis.

The objectives of this study were to evaluate the relative contribution of the direct pathway in overall brain transport for 17 model drugs with different physicochemical properties after nasal administrations and to identify factors that govern the fraction of the dose transported to the brain via the direct pathway (F(a, direct)). When the model drugs were nasally administered to rats, 5 of the 17 model drugs were delivered to a significant extent to the brain via the direct pathway. Multiple linear regression analyses showed that the correlation between various physicochemical properties and F(a, direct) was not statistically significant, indicative of a lack of primary physicochemical determinants in the direct transport pathway. Transporters such as rOAT3 and rOCT2 were expressed at significant levels in rat olfactory epithelia, and uptakes of standard substrates were significantly decreased in HEK293 cells expressing rOAT3 and rOCT2 in the presence of the five model drugs that were delivered to appreciable extents to the brain via the direct pathway. Therefore, these observations indicate that carrier-mediated transport may play a role in the brain delivery of drugs from the nose via the direct transport pathway.

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