Ussing chamber method

Even though the Ussing chamber method is used mostly to study drug permeability in liquid-liquid interphase, it has been demonstrated by Osth et al. 

Araya H, Tomita M, Hayashi M (2006) The novel formulation design of self-emulsifying drug delivery systems (SEDDS) type O/W microemulsion III The permeation mechanism of a poorly water soluble drug entrapped O/W microemulsion in rat isolated intestinal membrane by the Ussing chamber method. Drug Metab Pharmacokinet 21 45-53. 

Sugiyama T, Yamamoto A, Kawabe Y, Uchiyama T, Quan Y-S-, and Muranishi S. Effects of Various Absorption Enhancers on the Intestinal Absorption of Water Soluble Drugs by in vitro Ussing Chamber Method Correlation with an in situ Absorption Experiment. Biol Pharm Bulll997 20 812—814. 

We also studied the transport of insuHn across colonic membranes in the presence of various absorption enhancers, again using the Ussing chamber method [19]. Insulin transport was enhanced by the addition of NaDC, EDTA, w-lauryl-y9-D-malto-pyranoside (LM) and Na caprate (NaCap)... 

We also investigated the effect of acylation on the permeability of insulin across the intestinal membrane, using an in vitro Ussing chamber method [58]. The isolated intestinal segments without the muscu-laris and serosal layer were mounted with rings in the chamber, and insulin permeability across four different intestinal regions was determined. Insulin permeability was relatively low, but the order of its membrane permeability was jejunum> ileum > duodenum = colon. For the permeation of caproyl derivatives, the more lipophilic compound was found to have better permeability in the duodenum and colon... 

The permeability of TG analogs across the intestinal membrane was estimated using an in vitro Ussing chamber method... 

Osth K, Grasjo J, Bjork E (2002) A new method for drug transport studies on pig nasal mucosa using a horizontal Ussing chamber. J Pharm Sci 91 1259-1273. 

G. M.M. (2006) Innovative methods to study human intestinal drug metabolism in vitro precision-cut slices compared with Ussing chamber preparations. Drug Metabolism and Disposition The Biological Fate of Chemicals, 34, 1893-1902. 

Ussing chamber measurements are the most commonly used method to investigate transepithelial ion transport [164, 165], They can be performed on either functional epithelia from biopsies or on cultivated epithelia. The Ussing chamber itself is more or less a U-shaped chamber, which is compartmentalized by an epithelial cell layer and solute flux between both compartments can be measured. Electrogenic ion fluxes can be measured directly by short circuit measurements or calculated from open circuit measurements [165], Non-electrogenic solute flux needs continuous concentration measurements for each compartment separately [166]. Thus, Ussing chamber experiments enable to study permeation kinetics for secretion and resorption separately [166-169] and to evaluate effects on ion transport pathways [85, 87, 90, 170]. 

In addition to cell-based models, tissue-based models such as the Ussing chamber technique, the everted gut sac approach, and perfused isolated intestinal segments are also used, but only when it is important to understand the absorption processes in more detail. Unlike Caco-2, tissue-based models have the correct physiological levels of transporters and the presence of an apical mucus layer. Also, in situ and isolated organ perfusion methods exist for the gut, liver, lungs, kidneys, and brain and can provide data not directly obtainable in vitro. The isolated perfused liver is particularly useful since it allows an assessment of first-pass hepatic clearance, the quantitative distribution of metabolites in liver, blood, and bile, the effects of binding to plasma proteins and intracellular sites, and cellular uptake processes. 

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