Molecular design availability

An important approach to the graphic representation of molecules is the use of a connection table. A connection table is a data base that stores the available bond types and hybridizations for individual atoms. Using the chemical formula and the connection table, molecular stmctures may be generated through interactive graphics in a menu-driven environment (31—33) or by using a linear input of code words (34,35). The connection table approach may be carried to the next step, computer-aided molecular design (CAMD) (36). 

It has been demonstrated that a variety of different polyphosphazenes can be developed as biomaterials, membranes or hydrogels, bioactive polymers, and bioerodible polymers. As with most new areas of polymer chemistry and biomaterials science, molecular design forms the basis of most new advances, but the rate-controlling step is the testing and evaluation of the materials in both in vitro and in vivo environments. This is particularly true for polyphosphazenes where the availability of research quantities only has limited the... 

Bioavailability is defined as the portion or fraction of a chemical that is available for biological action and is influenced by several factors including the molecular size and charge of a molecule, structural features of membranes, first pass metabolism, and therefore, bio availability can be influenced by the molecular structure of a chemical. This situation presents an opportunity for molecular designers to manipulate a chemical s structure to decrease bioavailability and consequently hazard. If the availability of a molecule can be decreased, the amount of chemical at the site of action is decreased which leads to decreased toxicity. 

FL097, Graphics and Molecular Mechanics Software for Drug Design. Available from Colin McMartin cmcma ix.netcom.com. 

The correct understanding of the relationships between chemical structure and properties in surfactants is most important to both their effective use in many applications and to molecular designing of new surfactants. Some reliable information is available on various structural effects in ionic surfactants. On the other hand, only a limited amount of reliable information is a-vailable for nonionics with much of the data in the literature being insufficient both in reliability and in the variety of structures dealt with, mainly because of the difficulty in obtaining well-characterized compounds. 

CAS Online, available from Chemical Abstract Service, Columbus, Ohio. MACCS and MACCS-3D, available from Molecular Design Ltd, Hayward, California. 

RECCAS, available from Molecular Design Ltd, Hayward, California. P. A. Zurer (1985). Chem. Eng. News, 63,21 SYNLIB will be available from Distributed Graphics Ltd, J. Haggin (i 983). Chem. Eng. News, 61, 7. 

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