How many steps are required to model permeation through ion channels? This question is investigated by comparing one- and two-step models of permeation with experiment and MD simulation for the first time. In recent MD simulations, the observed permeation mechanism was identified as resembling a Hodgkin and Keynes knock-on mechanism with one voltage-dependent rate-determining step [Jensen et al...

We investigate theoretically and experimentally how the rate and extent of membrane permeation is affected by switching the donor delivery solvent from water to squalane for different permeants and membranes. In a model based on rate-limiting membrane diffusion, we derive explicit equations showing how the permeation extent and rate depend mainly on the membrane-donor and membrane-receiver part...

Excised human skin is utilized for in vitro permeation experiments to evaluate the safety and effect of topically-applied drugs by measuring its skin permeation and concentration. However, ethical considerations are the major problem for using human skin to evaluate percutaneous absorption. Moreover, large variations have been found among human skin specimens as a result of differences in age, ...

Nicotine transdermal systems are being used as an aid to smoking cessation programs. As the kinetics of nicotine delivery is important in success of a smoking cessation program, rapid and high input of nicotine is required, which is not possible by passive methods and requires enhancement strategies such as iontophoresis. Iontophoretic permeation, of nicotine looks promising, based on published...

Nicotine transdermal systems are being used as an aid to smoking cessation programs. As the kinetics of nicotine delivery is important in success of a smoking cessation program, rapid and high input of nicotine is required, which is not possible by passive methods and requires enhancement strategies such as iontophoresis. Iontophoretic permeation, of nicotine looks promising, based on published...

antimicrobial therapy remains to be the most important method of wound infection treatment. systemically administered antimicrobials may not achieve therapeutic level in wound. on the other hand, in the absence of surgical debridement (due to any reason), most topically applied antimicrobials cannot penetrate the wound in therapeutic amount due to the presence of eschar. burn eschar is a protei...

nicotine transdermal systems are being used as an aid to smoking cessation programs. as the kinetics of nicotine delivery is important in success of a smoking cessation program, rapid and high input of nicotine is required, which is not possible by passive methods and requires enhancement strategies such as iontophoresis. iontophoretic permeation, of nicotine looks promising, based on published...

The permeation pathway of macromolecules and nanospheres through skin was evaluated using fluorescent isothiocyanate (FITC)-dextran (average MW, 4 kDa) (FD-4) and nanospheres (500 nm in diameter) in hairless rat abdominal skin and porcine ear skin as well as a three-dimensional cultured human skin model (cultured skin model). A low molecular hydrophilic compound, sodium fluorescein (FL) (MW, 37...

In this work a new resistance model has been presented based on that of Henis-Tripodi which can be used for interpretation of gas permeation data in composite and asymmetric membranes. In contrast to the previous works, in this model the fraction of the support layer surface that includes the pores filled with coating material has been taken into account. The influences of the filled pores on s...

Antimicrobial therapy remains to be the most important method of wound infection treatment. Systemically administered antimicrobials may not achieve therapeutic level in wound. On the other hand, in the absence of surgical debridement (due to any reason), most topically applied antimicrobials cannot penetrate the wound in therapeutic amount due to the presence of eschar. Burn eschar is a protei...