| Autor: |
Chien, Yie Wen, Olson, Carter L., Sokoloski, Theodore D. |
| Zdroj: |
Journal of Pharmaceutical Sciences; March 1973, Vol. 62 Issue: 3 p435-440, 6p |
| Abstrakt: |
A new rapid response technique was developed to measure both steady-state and nonsteady-state flux (mass transport rate, moles per second) through membranes. The system utilizes a rotating-disk electrode, which is covered with a porous membrane and connected to a polarographic module. The rotating-disk configuration provides a uniform flux density over the entire surface of the membrane. Since flux is directly measured as current, there is no need to construct a concentration versustime plot to obtain steady-state permeability and there is no need to rely on lag time to measure effective diffusivity. The use of lag times for this purpose has recently been shown to introduce significant errors in estimating diffusivity. In this technique, the membrane is placed on the surface of the electrode. In the receiving compartment, response to flux is so rapid that nonsteady-state diffusion may be characterized. Moreover, it is possible to determine steady-state flux in the same experimental trial in short time periods. The technique and its use are described and theoretically explained through basic electrochemical and diffusion principles. The reproducibility achieved in transport measurements is seen to be quite good. |
| Databáze: |
Supplemental Index |
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