Colonic drug absorption enhancers

Table 4 Some common colonic drug absorption enhancers...

M Tomita, M Shiga, M Hayashi, S Awazu. Enhancement of colonic drug absorption by the paracellular permeation route. Pharm Res 5 341-346, 1988. 

Cheek, J.M., Kim, K.-J., and Crandall, E.D., NOj decreases paracellular resistance to ion and solute flow in alveolar epithelial monolayers, jcp. Lung Res., 16 561-575 (1990). Rangachari, P.K., Prior, T., and MeWade, D., Epithelial and mucosal preparations from canine eolon responses to substanee P, J. Pharmacol Exp. Ther., 254 1076-1083 (1990). Tomita, M., Hayashi, M., Toshiharu, H., and Awazu, S., Enhancement of colonic drug absorption by the transcellular permeation route, Pharm. Res., 5 786-789 (1988). 

Swenson ES, Milisen WB, Curatolo W (1994) Intestinal permeability enhancement structure-activity and structure-toxicity relationships for nonylphenoxypolyoxyethylene surfactant permeability enhancers. Pharm Res 11 1501-1504 Tomita M, Hayashi M, Horie T, Ishizawa T, Awazu S (1988) Enhancement of colonic drug absorption by the transcellular permeation route. Pharm Res 5 786-789 Tomita M, Sawada T, Ogawa T, Ouchi H, Hayashi M, Awazu S (1992) Differences in the enhancing effects of sodium caprate on colonic and jejunal drug absorption. Pharm Res 9 648-653... 

Ophthalmic Drug Delivery Systems, edited by Ashim K. Mitra 59. Pharmaceutical Skin Penetration Enhancement, edited by Kenneth A. Walters and Jonathan Hadgraft 60. Colonic Drug Absorption and Metabolism, edited by Peter R. Bieck... 

Pertinent to absorption enhancement of drugs it is noteworthy that because of the long residence time of the colon contents, it can be considered as a closed biological compartment ... 

Sekine M, Maeda E, Sasahara K, Okada R, Kimura K, Fukami M, Awazu S (1985) Improvement of bioavailability of poorly absorbed drugs. III. Oral acute toxicity and local irritation of medium chain glyceride. J Pharmacobio-Dyn 8 633-644 Shimazaki T, Tomita M, Sadahiro S, Hayashi M, Awazu S (1998) Absorption-enhancing effects of sodium caprate and palmitoyl carnitine in rat and human colons. Dig Dis Sci 43 641-645... 

Tomita, M. Sawada, T. Ogawa, T. Ouchi, H. Hayashi, M. Awazu, S. Differences in the enhancing effects of sodium caprate on colonic and jejunal drug absorption. Pharm. Res. 1992, 9, 648-653. 

Various formulation concepts have been introduced as potential ways to protect peptide and protein drugs from the hostile GI environment to increase their oral absorption such as use particulate drug carriers (microspheres, lipo-somes, and lectins), coadministration of enzyme inhibitors and absorption enhancers, use of chemical modification (prodrug), and site-specific delivery to the colon or rectum. Some of these approaches are discussed later. 

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