PubMed · 5093521
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K O Pedersen. 1971. Multiple small sample ultrafiltration without special apparatus.. https://doi.org/10.3109/00365517109090663
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This study examined whether lidocaine molecules can be transported through an artificial membrane by the application of AC. A cellophane membrane was placed between donor and receptor compartments. The donor compartment was filled with lidocaine hydrochloride (40 and 60 mmol/l) and the receptor compartment with pure water. A sine wave at 5 voltage levels and 5 frequencies was applied between the parallel plate electrodes. The impedance of the solution in the receptor compartment was measured to determine the concentration of the lidocaine. The transportation efficiency in the condition of high concentration was markedly enhanced with the application of 15 and 20 V at every frequency. Although no frequency dependence was observed in the 500 Hz to 100 kHz range, the transportation efficiency was markedly enhanced at 1 MHz. It is considered that lidocaine ions are transported by vibration or rotation energy induced by AC. The formation of electrode polarization is decreased in the high-frequency range resulting in attenuation of the voltage drop in the solution and increase of the transportation efficiency with the passage of AC.
Water transfer through different films, as a function of the physical state of water in contact with the film, the relative humidity difference, and the water vapor pressure difference, was investigated. The films were two synthetic packagings (hydrophobic polyethylene and hydrophilic cellophane) and an edible film. The physical state of water affects water sensitive films, such as cellophane, inducing a higher liquid water transfer due to interactions with the polymer. For hydrophobic polymers, such as polyethylene, neither the physical state of water nor the relative humidity has an influence on the water permeability. In complex system, such as an edible film composed of hydrophilic particles dispersed in a lipid phase, barrier efficiency is influenced by the continuous hydrophobic phase but could also be affected by the physical state of water due to the presence of hydrophilic compounds.