Enhanced permeation

Cations Increase Activity and Enhance Permeation of Pectinesterase in Ultrafiltration... 

Ultrafiltration of heterogenous colloidal suspensions such as citrus juice is complex and many factors other than molecular weight contribute to fouling and permeation. For example, low MW aroma compounds were unevenly distributed in the permeate and retentate in UF in 500 kd MWCO system (10). The authors observed that the 500 kd MWCO UF removed all suspended solids, including pectin and PE. If PE is complexed to pectate in an inactive complex, then it is conceivable that release of PE from pectin with cations will enhance permeation in UF. At optimum salt concentration, less PE activation was observed at lower pH values than at higher pH (15). In juice systems, it is difficult to separate the effect of juice particulates on PE activity. Model studies with PE extracts allows UF in the absence of large or insoluble particulates and control of composition of the ultrafilter. In... 

The titanosilicate version of UTD-1 has been shown to be an effective catalyst for the oxidation of alkanes, alkenes, and alcohols (77-79) by using peroxides as the oxidant. The large pores of Ti-UTD-1 readily accommodate large molecules such as 2,6-di-ferf-butylphenol (2,6-DTBP). The bulky 2,6-DTBP substrate can be converted to the corresponding quinone with activity and selectivity comparable to the mesoporous catalysts Ti-MCM-41 and Ti-HMS (80), where HMS = hexagonal mesoporous silica. Both Ti-UTD-1 and UTD-1 have also been prepared as oriented thin films via a laser ablation technique (81-85). Continuous UTD-1 membranes with the channels oriented normal to the substrate surface have been employed in a catalytic oxidation-separation process (82). At room temperature, a cyclohexene-ferf-butylhydroperoxide was passed through the membrane and epoxidation products were trapped on the down stream side. The UTD-1 membranes supported on metal frits have also been evaluated for the separation of linear paraffins and aromatics (83). In a model separation of n-hexane and toluene, enhanced permeation of the linear alkane was observed. Oriented UTD-1 films have also been evenly coated on small 3D objects such as glass and metal beads (84, 85). 

Shin SC, and Kim JY (2000) Enhanced permeation of triamcinolone acetonide through the buccal mucosa. Eur. J. Pharm. Biopharm. 50 217-220. 

Trihydroxy bile salts have also been proven to be effective. Enhanced permeation of mannitol in TR 146 cells (a model for oral cavity mucosa) was noticed when the concentration of sodium taurocholate and sodium glycocholate was about 2- to 3-fold higher than their... 

Vaddi, H.K., P.C. Ho, and S.Y. Chan. 2002. Terpenes in propylene glycol as skin-penetration enhancers Permeation and partition of haloperidol, Fourier transform infrared spectroscopy, and differential scanning calorimetry. J Pharm Sci 91 1639. 

Most gene therapy applications require extravasation of the DNA carriers so that only relative small DNA complexes can pass through the blood vessels and interact directly with parenchymal cells after vascular administration [2]. Under pathophysiological conditions, the structure of the vasculature can change. This phenomenon - termed the enhanced permeation effect - has been utilized to passively target macromolecules to tumors, since blood vessels in tumors are relatively more leaky. 

By utilizing polymerization in the miniemulsion system, larger HPG analogues can be created by linking several HPG units to a nanoparticle in order to obtain an optimum diameter of 50 nm [116], This size range is considered to be ideal for drug delivery carriers that may accumulate in tumors or inflamed tissue by the enhanced permeation and retention effect (EPR) [52],... 

In a disclosure regarding the use of alicyclic carboxylic acid oxycarbonylmethyl esters and their use as odorants and perfumes, a composition was described in which two furan compounds were components <2005W02005108534>. 4,5-Dimethyl-3-hydroxy-2(577)-furanone 80 and 3a,6,6,9a-tetramethyldodecahydronaphtho[2,l- ]-furan 18 were present in <2% in the described perfume. In another fragrance-related application, compound 18 was a component of a perfume composition which was added to a shampoo formulation designed to enhance permeation as well as provide desired fragrant effects <2002JPP2002241238>. The fused tricyclic furan 18 was incorporated as 20% of the perfume mixture of which that was a component of the shampoo in 0.7%. 

Azone, as expected, slightly increased permeation. Similarly, while Azone enhanced permeation of DEBT, both retarder compounds reduced permeation. Although these data provide initial validation of the basic hypothesis for the mechanism of skin modulation, much remains tobeaccomplished before these compounds can be considered as viable strategies for irritation or sensitization reduction. 

Bellara, S.R. Cui, Z.F. Pepper, D.S. Gas sparging to enhance permeate flux in ultrafiltration using hollow fibre membranes. J. Membr. Sci. 1996, 121, 175-184. 

The skin permeation of ACV (Zovirax cream) applied as a finite dose was promoted to a greater extent as the duration of brush treatment was extended (Fig. 5.2). A significant increase in ACV transport was observed following brush treatment (p < 0.05). The use of iontophoresis proved generally less effective than employing the rotating brush in enhancing permeation. For example the effect of 10-min anodal iontophoresis on the skin permeation of ACV proved to be comparable to that obtained after application of brush treatment at SOON m" for 10s (Table 5.2). The iontophoretic method in this study employed optimum conditions (electrode type, anode pFl of buffer, 7.4 current intensity. 

Glycols Very commonly used, good range of solubilising effects Occasional adverse reactions reported. Act synergistically with other solvents to enhance permeation... 

Hou SYE, Flynn GL. Azone enhanced permeation of skin. Mediation of penetration of benzoic acid as a function of pH. Pharm Res 1986 3(suppl) 52S. 

This is unfortunate because the theoretical advantage of nanosystems is their small size, allowing freer movement than microspheres in the circulation, including the lymph and in tissues. Flow rates are important not least in the determination of the possibility of nanoparticle interaction with endothelial receptors prior to internalization, or indeed in the decoupling of carriers and receptors due to shear forces. Flow of nanoparticles is a vital element in extravasation and in the enhanced permeation and retention (EPR) effect. What is the influence of nanoparticle size on particle flow in the circulation And, with the advent of CNTs in particular, what is the influence of shape on flow and fate CNTs certainly behave differently in the blood from spherical C60 fidlerenes. CNTs activate human platelets and induce them to aggregate, whereas their spherical analogues do not... 

---