Journal of Pharmaceutical Sciences 1983-02-01

Kinetics and thermodynamics of interfacial transfer.

R Fleming, R H Guy, J Hadgraft

Index: J. Pharm. Sci. 72(2) , 142-5, (1983)

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Abstract

The kinetic barrier against the transport of methyl and ethyl nicotinates across the water-isopropyl myristate interface has been studied as a function of temperature using a rotating diffusion cell. The temperature dependence of the interfacial transfer kinetics has enabled calculation of the thermodynamic parameters for the process. It is evident from the results that, for the transferring solutes considered, the activation energy barrier is enthalpic, because there is a large positive entropy for transfer into the interfacial region.