Permeability enhancers

Such a composition reduces friction, permeates drilling mud wall cake, destroys binding wall cake, and reduces differential pressure. Unfortunately, many of such compositions are toxic to marine life. Synthetic PAOs are nontoxic and effective in marine environments when used as lubricants, retum-of-permeabiUty enhancers, or spotting fluid additives for water-based drilling muds. A continuing need exists for other nontoxic additives for water-based drilling muds, which serve as lubricants, retum-of-permeability enhancers, and spotting fluids. 

Treating a coal seam with a well treatment fluid containing a dewatering agent will enhance methane production through a well. This additive enhances the permeability of the formation to water production and binds tenaciously to the coal surface so that the permeability-enhancement benefits are realized over a long production term. 

Where an unusual excipient is chosen, or where an established excipient is chosen for a dosage form that results in its administration by a novel route of administration, then additional data will need to form part of the application. In effect, a novel excipient will need to be supported by data similar to those required for a new drug, with full supporting data including composition, function, and safety. Novel excipients include the components of the matrix in prolonged release products, new propellants, and new permeability enhancers. The exception to this need for extensive supporting data would be for a material already approved for food use and administered by the oral route or a material already approved for cosmetic use with a topical route of administration. In all cases the quality of the excipients has to be described adequately and shown to be satisfactory (which will depend on its role). 

KM Morimoto, T Nakai, K Morisaka. (1987). Evaluation of permeability enhancement of hydrophilic compounds and macromolecular compounds by bile salts through rabbit corneas in vitro. J Pharm Pharmacol 39 124-126. 

Swenson, E. S., Milisen, W. B., Curatolo, W., Intestinal permeability enhancement efficacy, acute toxicity and reversibility, Pharm. Res. 1994, 11, 1132-1142. 

Nielsen HM, Rassing MR (1999a) TR146 cells grown on filters as a model of human buccal epithelium III. Permeability enhancement by different pH values, different osmolality values, and bile salts. Int J Pharm 185 215-225... 

Swenson EC, Curatolo WJ (1992) Intestinal permeability enhancement for proteins, peptides and other polar drugs Mechanisms and potential toxicity. Advanced Drug Delivery Reviews 8 39-92... 

Haemolytic activity and the permeability-enhancing activity of nonionic alkyl ethers correlate well (23). 

Notman, R., den Otter, W.K., Noro, M.G., Briels, W.J., Anwar, J. The permeability enhancing mechanism of DMSO in ceramide bilayers simulated by molecular dynamics. Biophys. J. 2007,93, 2056-68. 

Given such difficulties, it is not unsurprising that bioavailabilities below 1 % are often recorded in the context of oral biopharmaceutical drug delivery. Strategies pursued to improve bioavailability include physically protecting the drug via encapsulation, formulation as microemulsions/ microparticulates, as well as inclusion of protease inhibitors and permeability enhancers. 

CItIchollne Tablet Injection Membrane permeability enhancer... 

Swenson, E.S., W.B. Milisen, and W. Curatolo. 1994. Intestinal permeability enhancement Efficacy, acute local toxicity, and reversibility. Pharm Res 11 1132. 

Xia, W.J., and H. Onyuksel. 2000. Mechanistic studies on surfactant-induced membrane permeability enhancement. Pharm Res 17 612. 

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