The skin has been used as a port for systemic delivery of therapeutic agents since several decades. The composition of stratum corneum renders it a daunting barrier to the topical and transdermal administration of therapeutic agents. The number of drug molecules for transdermal delivery is limited owing to the physicochemical restrictions. Iontophoresis is an effective technique for physically ...

Bilayer asymmetry in the apical membrane may be important to the barrier function exhibited by epithelia in the stomach, kidney, and bladder. Previously, we showed that reduced fluidity of a single bilayer leaflet reduced water permeability of the bilayer, and in this study we examine the effect of bilayer asymmetry on permeation of nonelectrolytes, gases, and protons. Bilayer asymmetry was ind...

This paper is an early, and possibly premature, examination of some consequences of different mechanisms of ion permeation in the hope of providing a basis for progressing beyond the present treatments of bioelectric phenomena (cf. Hodgkin, Huxley, and Katz, 1952a, b, c, d, e) which, in the absence of knowledge of the details of the mechanism by which ions cross biological membranes, have neces...

Transdermal delivery of ondansetron hydrochloride is one of the promising ways to maximize the therapy in contrast to oral delivery. Current investigation efforts are focused in formulating the ondansetron hydrochloride matrix-type transdermal film by incorporating hydrophilic and hydrophobic polymers. In this study, ondansetron hydrochloride transdermal films were prepared using solvent evapor...

Tisato Kajiyama Faculty of Engineering, Kyushu University, Fligashi-ku, Fukuoka 812 A bimolecular membrane of phospholipids such as lecithin is in a state of liquid crystal capable of reversible structural modifications and its permeation property depends on such reversible change. Artificial amphiphiles with monoalkyl and dialkyl groups form multilamellar liposome composed of the bimolecular l...

The variety of physiologic and biologic functions of zinc is fascinating and could be applicable to medicine. Our previous studies demonstrated that the absorption of zinc after oral administration to rats is dose-dependent. In order to clarify the detailed mechanism of the dose-dependent in vivo absorption, the transport of zinc across intestinal epithelial cells was investigated using Caco-2 ...

Experiments indicated that tritium permeation in 316 austenitic stainless steel is enhanced by a factor of ∼2-5 after irradiation as compared to the ex-reactor results. To understand this enhancement, we have performed extensive molecular dynamics simulations to study the effects of both the grain boundary structure (Σ3{111}, Σ5{100} and Σ11{311}) and the nature of point defects (vacancy, inter...

Escherichia coli lactose permease (LacY) transports sugar across the inner membrane of the bacterium using the proton motive force to accumulate sugar in the cytosol. We have probed lactose conduction across LacY using steered molecular dynamics, permitting us to follow molecular and energetic details of lactose interaction with the lumen of LacY during its permeation. Lactose induces a widenin...

Bile salts are ionic amphiphilic compounds with a steroid skeleton. Among the most important physiological properties of bile salts are lipid transport by solubilization and transport of some drugs through hydrophobic barriers. Bile salts have been extensively studied to enhance transepithelial permeability for different marker molecules and drugs. They readily agglomerate at concentrations abo...

1. Abstract: The objective of this work was to develop suitable film formulations of ketorolac tromethamine (KT) for transdermal use and to investigate the effect of film composition and permeation enhancers on the in-vitro release and skin permeation of the drug. Polyvinyl alcohol (PVA), sodium carboxymethylcellulose (NaCMC), and chitosan were used as film-forming polymers. The adhesive hydrop...