Structure-Property Relationships SPR

In the second half of the nineteenth century the structural theory of organic chemistry was developed. It led to the concept that chemical, physical and biological properties of all kinds must vary with structural change. The earliest structure-property relationships (SPR) were qualitative. With the development of methods of quantitative measurement of these properties data accumulated. Attempts were then made to develop quantitative models of the structural dependence of these properties. These methods for the quantitative description of structural effects will now be described. 

A tiered testing and evaluation scheme is presented that combines pre-existing information on serious ocular tissue damage and on eye irritation (including data relating to historical human or animal experience) as well as considerations on structure-activity relationships (SAR) or structure-property relationships (SPR) and the output of validated in vitro tests in order to avoid unnecessary animal testing. 

Inherent in the concept of molecular structure is the notion that properties of all kinds, chemical, physical and biological, must vary with structural change. At first the structure -property relationships (SPR) reported were qualitative. As quantitative measurements of... 

The molecular structure of any chemical will determine all of its physical, chemical and biological properties. Discovery chemists will therefore seek correlations between molecular structure and a desired property and the search for novel materials is therefore often guided by structure/ activity relationships (SARs). These can also be referred to as structure/ property relationships (SPRs) and when carried out with data inputs in a numerical form and using statistical methods for their analysis, the adjective quantitative is added giving quantitative structure/activity... 

All these assays allow chemists, toxicologists, and biologists to obtain actionable information and provide a link between stracture-activity relationship (SAR) and structure-property relationship (SPR) that drive decisions on the selection of chemical series and molecules. 

Hence, stmctural information can be lost leading to similarity values of unity for pairs of molecules that are not stracturally identical. Nevertheless, there is at least a partial correspondence between the descriptors in the directory and the binary molecular FP of a molecule, so that it may be possible in many instances to associate particular substmctural features with molecular properties and/or biological activities, a characteristic that is not generally shared by molecule-dependent FP representations vide infra). This can be partially ameliorated through the use of weighted molecular FPs that take account of the nmnber of times a stractural feature occurs in a molecule. However, since not all structural features that may be associated with a specific structure-property relationship (SPR) or stmcture-activity relationship (S AR) are necessarily accounted for in given FP, it may not be possible to infer SPR or SAR even when weighted FPs are employed. 

The existence of relationship between stmcture of drug preparations and efficiency of their pharmacological action makes the program packages based of the structure-property relationship (SPR) applicable for searching new structures of potential dmg candidates. 

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