Biologically active agents

Many fluorinated, biologically active agents have been developed and successfully used in the treatment of diseases. The biological property of fluorinated organics has been further extended to applications in the agrochemical and pest management fields. 

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

Biologically Active Agents from Helminthosporium sativum... 

Study of the transport of substances across membranes is an example. There is considerable knowledge of the transport of small molecules across living membranes this should be extended to studies of larger molecules. A more complete understanding of the transport of biologically active agents would be particularly important in diagnosis and therapy. 

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. 

This research has given insight to a very unique bicontinuous blend system. It has also shown that the pore structure and release rates from EVAc matrices are not only dependent on particle size and loading but also on the blending technique. It becomes apparent that it is possible to tailor these systems not only for release rates but also for initial time of release of insoluble biologically active agents. 

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

Price, R., Gaber, B. and Lvov, Y. (2001) In-vitro release characteristics of tetracycline, khellin and nicotinamide adenine dinudeotide from halloysite a cylindrical mineral for delivery of biologically active agents. Journal of Microencapsulation, 18, 713—723. 

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

Because they are crucial to the course of an organism s response, the rate and extent of absorption of biologically active agents from the GI tract also have major implications for the formulation of test material dosages and also for how production (commercial) materials may be formulated to minimize potential accidental intoxications while maximizing the therapeutic profile. 

Dolle, R., Comprehensive survey of chemical libraries yielding enzyme inhibitors, receptor agonists and antagonists, and other biologically active agents 1992 through 1997, Mol. Diversity, 1998, 3, 199-233. 

There is general agreement that the biologically active agent causing byssinosis is a lint contaminant derived either from the cotton plant itself or from a microbial contaminant of cotton. 

Berenhaum, M.C. 1981. Criteria for analyzing interactions between biologically active agents. Adv. Cancer Res. 35 269-335. 

Scheme 10.8 outlines the application of rhodium-catalyzed allyhc amination to the preparation of (il)-homophenylalanine (J )-38, a component of numerous biologically active agents [36]. The enantiospecific rhodium-catalyzed allylic amination of (l )-35 with the lithium anion of N-benzyl-2-nitrobenzenesulfonamide furmshed aUylamine (R)-36 in 87% yield (2° 1° = 55 1 >99% cee) [37]. The N-2-nitrobenzenesulfonamide was employed to facilitate its removal under mild reaction conditions. Hence, oxidative cleavage of the alkene (R)-36 followed by deprotection furnished the amino ester R)-37 [37, 38]. Hydrogenation of the hydrochloride salt of (l )-37 followed by acid-catalyzed hydrolysis of the ester afforded (i )-homophenylalanine (R)-3S in 97% overall yield. 

Benzene and thiophene rings can of course often be interchanged in biologically active agents. The very broad structural latitude consistent with NSAID activity is by now a familiar theme as well. Preparation of the fused thiophene counterpart of the NSAID piroxicam (Chapter 11) starts with the reaction of thiophene (25-1), itself the product of a multistep sequence, with ethyl A-methylglycinate to give the sulfonamide (25-2). Treatment of that intermediate with a base leads to intramolecular Claisen condensation and thus the formation of the 3-ketoester (25-3). An amide-ester interchange with 2-aminopyridme (25-4) completes the synthesis of tenoxicam (25-5) [25]. 

Katsarava et al. (4) prepared biodegradable hydrogels, (III), consisting of epoxy-containing poly(ester amides), which were used as implantable medical devices for delivery of biologically active agents. 

The above paragraphs summarize some of the studies in this area, and indicate that in preparing potentially useful biologically active agents of all classes, thiophene and ben-zothiophene rings may replace benzene, naphthalene or indole rings to produce active compounds which may be less toxic, have different physiological disposition and/or different modes of metabolism or detoxification, and thus impart desirable properties. 

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