Drug-membrane interaction conditions

The observation made in the case of the above two examples leads to another possible effect of drug-membrane interaction a change in the preferred conformation or orientation of the drug molecule under the environmental conditions of the membrane. 

The example shows the great importance of the experimental conditions (lipid composition, temperature, lipid-drag concentration ratio, etc.), which have a decisive influence on the quality, type, and strength of drug-membrane interactions. Any further interpretation with respect to biological activity in vitro and in vivo can become risky. 

Most biomembranes are in the liquid crystalline phase under physiological conditions and their complex composition makes it more difficult to measure phase transitions. It should be mentioned that the effect of drug molecules on fluidity and order of a membrane can even be reversed below and above Tt [169] and NMR measurements of drug-membrane interactions are normally performed above Tt. 

Primarily to elucidate transporter localization and function, vesicles enriched in trophoblast apical or basolateral membranes have frequently been utilized. To give a few instances, they have been used to investigate P-gp-mediated transport, mechanisms of transport of cationic compounds, drug interactions with nutrient transport, and differences in amino acid transport in pathological conditions of the placenta [36, 40-42], Briefly, for preparation of microvillus membrane vesicles the cord, amniochorion and decidua are removed from placenta, and the tissue cut on the maternal side. The mince is stirred to loosen... 

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