Outer membrane permeation of Bacteroides fragilis by cephalosporins was examined by a previously described method. The permeation parameters of cephalosporins in B. fragilis were close to 10(-5) cm3/min per microgram of cell dry weight. These values were about an order of magnitude lower than those in Escherichia coli. In B. fragilis, the permeation was not directly proportional to the hydrophi...

I would like to address two key issues related to the Perspectives on Ion Permeation . The first is the estimate of the size of the physical forces relevant for ion transport. Any good physical model of ion permeation requires the identification of the dominant forces. The second subject concerns a careful definition of the terms “mean field” and “mean field approximation.” Several articles in ...

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...

Many properties of chemicals depend on their stereochemistry. Among these, the effects of stereoisomerism on percutaneous absorption of drugs are not well studied. We have previously shown that permeation of tretinoin and isotretinoin (two geometric isomers) through hydrophilic enhancers-treated rat skin is stereoselective. As, depending on their lipophilicity, penetration enhancers can change ...

Many properties of chemicals depend on their stereochemistry. Among these, the effects of stereoisomerism on percutaneous absorption of drugs are not well studied. We have previously shown that permeation of tretinoin and isotretinoin (two geometric isomers) through hydrophilic enhancers-treated rat skin is stereoselective. As, depending on their lipophilicity, penetration enhancers can change ...

The permeability of the cornea to drugs is clinically important because it is the major factor determining the efficacy of topically applied ophthalmic preparations. With this perspective, the present article gives a brief update and overview of corneal structure and proposed mechanisms of permeation. Physiological, physicochemical and formulation factors affecting drug permeation through corne...

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...

KEY POINTS Kainate receptor heteromerization and auxiliary subunits, Neto1 and Neto2, attenuate polyamine ion-channel block by facilitating blocker permeation. Relief of polyamine block in GluK2/GluK5 heteromers results from a key proline residue that produces architectural changes in the channel pore α-helical region. Auxiliary subunits exert an additive effect to heteromerization, and thus re...

the aim of the present study was to investigate the relationship between the polar surface area and other molecular properties of the model drugs and their transdermal permeability across the rat skin. few model drugs which are weakly acidic (ibuprofen, aceclofenac and glipizide) and weakly basic (olanzapine, telmisartan and sildenafil citrate) were selected for the study based on polar surface...

formulation by using chemical penetration enhancers and to study the effect of pulsed current on permeation through guinea pig, Wistar rat and human cadaver skin. Modified Franz diffusion cell was used to study the in vitro permeation across various types of skin by iontophoresis. The thermo-reversible gel was prepared and optimized by cold method using poloxamer 407 as a gelling agent. Thermo-...