Effect of ethanol on the transport

Effects of Ethanol on the Transport of /3-Estradiol in Hairless Mouse Skin... 

This paper describes the striking effects of ethanol on the transport of 3-estradiol in hairless mouse skin. 

The purpose of this report is to present results on (a) the effect of ethanol on the transport of 8-estradiol across hairless mouse skin and (b) the effect upon the effective permeability coefficient as solvent compositions are independently varied in the donor and receiver chambers. Also, since there is evidence for pore formation, at least at the highest ethanol levels, a novel pore model... 

Ghanem, A.-H. et al. The effects of ethanol on the transport of B-estradiol and other permeants in hairless mouse skin II. A new quantitative approach. Journal of Controlled Release 6 75-83, 1987. 

Sernka TJ, Gilleland CW, Shanbour LL. Effects of ethanol on active transport in the dog stomach. Am J Physiol 226 397-400, 1974. 

Effect of ethanol extracts of three Chinese medicinal plants with laxative CS318 properties on ion transport of the rat intestinal epithelia. Biol Pharm Bull 2004 27(2) 162-165. 

The extent to which surface transport affects global rates of reaction has not been established. For it to be important, adsorption must occur, but this is also a requirement for catalytic activity. Indirect evidence suggests that in some cases the effect is considerable. For example. Miller and Kirk found higher rates of dehydration of alcohols on silica-alumina than could be explained with only pore-volume diffusion to account for intraparticle resistances. They attributed the discrepancy to surface diffusion. Masamune and Smith found that surface transport of ethanol on silica gel at temperatures as high as 175°C predominated over gas-phase diffusion in the pore. In view of the data available, it seems wise at least to consider the possibility of surface migration in any evaluation of intraparticle effects. This can be done by adding a surface-diffusion contribution to the effective diffusivity considered in the previous section. The method of doing this is presented below, but its usefulness is still limited because of inadequate experimental and theoretical aspects of surface transport. 

Khawaja, J. A., Effect of ethanol ingestion on the nucleocytoplasmic transport of hepatic RNA, Toxicol. Lett., 15, 199, 1983. 

The nature of the dissolution medium can profoundly affect the shape of a dissolution profile. The relative rates of dissolution and the solubilities of the two polymorphs of 3-(3-hydroxy-3-methylbutylamino)-5-methyl-a5-triazino[5,6-Z)7indole were determined in USP artificial gastric fluid, water, and 50% ethanol solution [69]. In the artificial gastric fluid, both polymorphic forms exhibited essentially identical dissolution rates. This behavior has been contrasted in Fig. 6 with that observed in 50% aqueous ethanol, in which Form II has a significantly more rapid dissolution rate than Form I. If the dissolution rate of a solid phase is determined by its solubility, as predicted by the Noyes-Whitney equation, the ratio of dissolution rates would equal the ratio of solubilities. Because this type of behavior was not observed for this triazinoindole drug, the different effects of the dissolution medium on the transport rate constant can be suspected. 

CFD models of DEFC have been also proposed [188]. Suresh and Jayanti developed an one-dimensional, single phase, isothermal mathematical model for a liquid-feed DEFC, taking into account mass transport and electrochemical phenomena on both the anode side and the cathode side [189]. Tafel kinetics expressions have been used to describe the electrochemical oxidation of ethanol at the anode and the simultaneous ethanol oxidation and ORR at the cathode. The model in particular accounts for the mixed potential effect caused by ethanol cross-over at the cathode and is validated using the data from the literature. Model results show that ethanol crossover can cause a significant loss of cell performance. 

Tang et al. proposed a two-dimensional mathematical model of a tubular-based DEFC cathode, describing electrochemical kinetics and multi-component transport [193]. A spherical agglomerate model is used in the CL, and the effect of ethanol penetration on the ORR of the tubular cathode is also considered. The model, coded... 

Other aspects of formulation such as the nature of the binary or ternary vehicle (oil-surfactant, water-surfactant or oil-water-surfactant, respectively) have been considered recently [151], Addition of polysorbate 80 to the aqueous phase has no significant effect on the epidermal transport of ethanol, but a significant reduction in the transport of the less soluble octanol results, in line with the arguments presented above in isopropyl myristate, octanol transport is not affected by the solubilizer while that of ethanol is decreased. In the ternary systems identified in Fig. 7.35, the results in Table 7.14 were obtained indicating a general decrease in permeability constants for ethanol, butanol and octanol. The viscosity of the vehicles was not a factor although this varied from 1 to 39 X 10 cP. In the ternary systems a surfactant will distribute itself between the aqueous and non-aqueous phase quantitative prediction of permeation is made difficult even with data on the transport properties of the permeants in the individual phase. The results indicate that the percutaneous absorption of the... 

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