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The objective of this study was to investigate the effect of dispersion states of azone in gels on the transdermal permeation of levamisole hydrochloride (LH). LH hydroalcoholic gels containing azone of different dispersion states were prepared by varying the contents of azone and Tween 80, and the in vitro transdermal permeation of LH across excised rat skin was evaluated. Depending on the content of azone, mixed solvents, and solubilizer used, azone presented as dissolved molecules, solubilized in micelles, and fine or coarse emulsion droplets in gels. Dramatically increased transdermal permeation of LH within the azone contents between 0.25% and 0.75% indicated high transdermal enhancement efficiency of the molecular or micellar azone, and extra azone that existed as oil droplets did not fully exert transdermal penetration enhancement of LH. Although solubilizer (Tween 80) can greatly increase the solubility of azone, only small amount of Tween 80 (0.5%) in the gel significantly increased the steady-state flux of LH. Addition of extra amount of Tween 80 (>0.5%) reduced the amount of azone distributed in the skin, and thus decreased the transdermal drug permeation. The results partly elucidated the versatile effects of the dispersion states of azone on the transdermal permeation of hydrophilic drug from semisolid gels. [ABSTRACT FROM AUTHOR]

In the hybrid power system based on double-input buck converter and power management strategy which has been put forward, we can keep the system working under suitable mode. But when the two IGBT switches at the same time, due to the reverse bias voltage, the flywheel diode wiil cut off. The commercial power current must flow through the photovoltaic that wiil affect measurement of Photovoltaic current seriously. Interleaved dual-edge modulation and inter-lock can solve the problem, theoretical analysis wiil be listed to prove the consistency of the two method. The simulation results of interleaved dual-edge modulation based on Matlab/Simulink model have confirmed the effectiveness. [ABSTRACT FROM AUTHOR]