Drugs drug permeation

Michaels, AS Chandrasekaran, SK Shaw, JE, Drug Permeation Throngh Hnman Skin Theory and in vitro Experimental Measnrement, AIChE Journal 21, 985, 1975. 

Malkia A, Murtomaki L, Urtti A and Kontturi K. Drug permeation in biomembranes in vitro and in silico prediction and influence of physicochemical properties. Eur J Pharm Sci 2004 23 13-47. 

The simplest case of pharmacokinetics is intravenous injection [1]. In this case the drug is injected directly into the bloodstream. The drug may permeate to different tissues depending on its ability to get across the blood vessel walls and the cellular barriers in the particular tissue targets (Fig. 1). If the drug has small molecular weight and adequate... 

Most drugs are weak acids or bases. Since the unchanged form of a drug preferentially permeates across... 

Membrane permeation-controlled system in which the drug permeation is controlled by a polymeric membrane Transderm-Scop (scopolamine Ciba-Geigy). 

Drug Permeation Enhancement Theory and Applications, edited by Dean S. Hsieh... 

T Okano, YH Bae, H Jacobs, SW Kim. Thermally on-off switching polymers for drug permeation and release. J Controlled Release 11 255-265, 1990. 

Figure 12 Schematic representation for reversibly changing drug permeation through membranes by external modulation. M, indicates the diffused amount of drug at time t. 

Pagliara, A., Resist, M., Geinoz, S., Carrupt, P.-A., Testa, B., Evaluation and prediction of drug permeation,... 

Y., Taki, Y., Sakane, T., Nadai, T., Sezaki, H., Analysis of drug permeation across Caco-2 monolayer implications for predicting in vivo drug absorption, Pharm. Res. 1997,... 

There are two pathways by which a drug molecule can cross the epithelial cell the transcellular pathway, which requires the drug to permeate the cell membranes, and the paracellular pathway, in which diffusion occurs through water-filled pores of the tight junctions between the cells. Both the passive and the active transport processes may contribute to the permeability of drugs via the transcellular pathway. These transport pathways are distinctly different, and the molecular properties that influence drug transport by these routes are also different (Fig. 

Hammer and coworkers prepared PEG-h-PCL polymersomes entrapping DXR (Fig. 11a). The release of DXR from the polymersomes was in a sustained manner over 14 days at 37 °C in PBS via drug permeation through the PCL membrane, and hydrolytic degradation of the PCL membrane [228]. The release rate of encapsulated molecules from polymersomes can be tuned by blending with another type of block copolymer [229]. Indeed, the release rate of encapsulated DXR from polymersomes prepared from mixtures of PEG- -PLA with PEG- -PBD copolymers increased linearly with the molar ratio of PEG- -PLA in acidic media (Fig. lib). Under acidic conditions, the PLA first underwent hydrolysis and, hours later, pores formed in the membrane followed by final membrane... 

As described previously in this chapter, efforts have been made to develop methods for quantification of skin permeability, validation of diffusion cell setups, and correlation of in vitro data with the in vivo situation. However, the average drug permeation experiment does not provide insight into the temporal and local disposition within the tissue, that is, the skin penetration. The following discussion will give an overview of methods tackling this kind of problem. 

J. Swarbrick, G. Lee, and J. Brom. Drug permeation through human skin I. Effect of storage conditions of skin. J. Invest. Dermatol. 78 63-66 (1982). 

Frequently, histopathological examinations of tissues reveal invaluable information on their toxicities [11], The ability to screen various formulations quickly for both ciliotoxicity and other forms of epithelial toxicities is a strong positive attribute of the ex vivo models. Furthermore, advanced techniques such as confocal laser scanning microscopy can be used to study the drug permeation pathways of these tissues [12],... 

In Vitro Models for Investigations of Buccal Drug Permeation and... 

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