Active agents controlled release

Drugs are the most important class of active agents whose release needs to be controlled due to numerous medical reasons. Release of other active agents like fragrances, vitamins, or insect repellents might not be existential but they considerably facilitate everyday life. Control over release differs for different types of active agents and is strongly affected by the polymer wall they are encapsulated in and the textile support to which they are applied. 

Cosmetics and Pharmaceuticals. The main use of hexadecanol (cetyl alcohol) is in cosmetics (qv) and pharmaceuticals (qv), where it and octadecanol (stearyl alcohol) are used extensively as emoUient additives and as bases for creams, Hpsticks, ointments, and suppositories. Octadecenol (oleyl alcohol) is also widely used (47), as are the nonlinear alcohols. The compatibiHty of heavy cut alcohols and other cosmetic materials or active dmg agents, their mildness, skin feel, and low toxicity have made them the preferred materials for these appHcations. Higher alcohols and their derivatives are used in conditioning shampoos, in other personal care products, and in ingested materials such as vitamins (qv) and sustained release tablets (see Controlled RELEASE technology). 

R. W. Baker, Controlled Release of Biologically Active Agents,]oEn. Wiley Sons, Inc., New York, 1987. 

The concept of fibrous polymer formulations was extended to the delivery of aquatic herbicides (56). Several herbicides including Diquat, Fluridone, and Endothal were spun into biodegradable poly-caprolactone. Monolithic fibers and a modified monolithic system were produced with levels of herbicide from 5 to 60% by weight. Laboratory and field trials showed efficacious delivery of the active agent. Fibers provided both targeted localized delivery and controlled release of the herbicide to the aquatic weed. 

Yolles, S., Leafe, T., Sartori, M., Torkelson, M., Ward, L., and Boettner, P., Controlled release of biologically active agents in Controlled Release Polymeric P ormulations (D. R. Paul and F. W. Harris, eds.), American Chemical Society, Washington, D.C., 1976, Chap. 8. 

Lewis, D. H., and Dunn, R. L., Stolle Research and Development Corp., Controlled release aquatic biologically active agent formulations, Eur. Patent Appl. EP 126827 Al, Dec. 5, 1984. 

The use of polymers for biomedical applications has been widely accepted since the 1960 s (7), and specifically for controlled release applications since the 1970 s (2). The primary goal of this research was to create a controlled release matrix from polymers with pre-existing Food and Drug Administration (FDA) histories, which would be capable of releasing insoluble active agents, and upon exhaustion of the device, leave a stable, inert, removable skeleton. The application of such a matrix would be as an intracervical device which would prevent both conception and ascending infection. 

AC Tanquary, RE Lacey. Controlled release of biologically active agents. Adv Exp Med Biol 47 73-98, 1974. 

Price, R. and Gaber, B. Controlled Release of Active Agents Using Inorganic Tubules, US Patent 5,651,976. Price, R. Sustained Delivery of Active Compounds from Tubules with Rational Control, US Patent 5,705,191. Price, R. Method of Controlled Release and Controlled Release Microstructures, US Patent 6,280,759. Price, R. Efficient Method for Subsurface Treatment, Including Squeeze Treatment, US Patent6, 401,816. 

Gaber,B.,Price,R.,Santos,J.P.andVittal, V. (2001) Entrapment and controlled release of active agents from halloysite. Rocks Minerals, 76, 211-215. 

Wagner E (1998) Effects of membrane-active agents in gene delivery. J Control Release 53 155-158... 

Compositions for controlled release of a biologically active agent, and the preparation thereof, US Pat., 7112339. 

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